IUPAC-NIST Solubility Data Series. 90. Hydroxybenzoic Acid Derivatives in Binary, Ternary, and Multicomponent Systems

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provided by Research Repository IUPAC-NIST Solubility Data Series. 90. Hydroxybenzoic Acid Derivatives in Binary, Ternary, and Multicomponent Systems. Part I. Hydroxybenzoic Acids, Hydroxybenzoates, and Hydroxybenzoic Acid Salts in Water and Aqueous Systems

Ayako Goto, Editor a) University of Shizuoka, Shizuoka 422-8526, Japan

Hiroshi Miyamoto, Editor Niigata University, Niigata 950-2181, Japan

Mark Salomon, Editor MaxPower, Inc., 141 Christopher Lane, Harleysville, Pennsylvania 19438

Rensuke Goto, Evaluator University of Shizuoka, Shizuoka 422-8526, Japan

Hiroshi Fukuda, Evaluator Kitasato University, Kanagawa, 252-0373, Japan

Erich Königsberger, Compiler and Lan-Chi Königsberger, Compiler Murdoch University, Murdoch, Western Australia WA6150, Australia

͑Received 13 October 2010; accepted 8 November 2010; published online 22 February 2011͒

The solubility data for well-deﬁned binary, ternary, and multicomponent systems of solid-liquid type are reviewed. One component, which is 2-, 3-, and 4-hydroxybenzoic acids, 4-hydroxybenzoate alkyl esters ͑parabens͒, or hydroxybenzoic acid salts, is in the solid state at room temperature and another component is liquid water, meaning that all of the systems are aqueous solutions. The ternary or multicomponent systems include organic substances of various classes ͑hydrocarbons of several structural types, halogenated hydrocarbons, alcohols, acids, ethers, esters, amides, and surfactants͒ or inorganic substances. Systems reported in the primary literature from 1898 through 2000 are compiled. For seven systems, sufﬁcient binary data for hydroxybenzoic acids or parabens in water are available to allow critical evaluation. Almost all data are expressed as mass and mole fractions as well as the originally reported units, while some data are expressed as molar concentration. © 2011 American Institute of Physics. ͓doi:10.1063/1.3525876͔

Key words: Aqueous systems; hydroxybenzoic acid; hydroxybenzoic acid salt; paraben; salicylic acid; solubility.

CONTENTS Hydroxybenzoic Acid Salts in Binary Aqueous Systems...... 5 1. Preface...... 3 2.1. Hydroxybenzoic acid–water systems...... 5 1.1. Scope of the volume...... 3 2.1.1. Critical evaluation of the solubility 1.2. Experimental methods...... 4 of hydroxybenzoic acids...... 5 1.3. Procedure used in critical evaluation...... 5 2.1.1.1. Salicylic acid ͑2-hydroxybenzoic acid͒.... 5 2. Hydroxybenzoic Acids, Parabens, and 2.1.1.2. 3-Hydroxybenzoic acid. . . . 11

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2.2.1. Critical evaluation of the solubility 3.2.2.4. Polyethylene glycol of parabens...... 18 derivatives...... 104 2.2.1.1. Methylparaben...... 18 3.2.3. Propylparaben...... 106 2.2.1.2. Ethylparaben...... 23 3.2.3.1. Alcohols...... 106 2.2.1.3. Propylparaben...... 27 3.2.3.2. Carbohydrate...... 106 2.2.1.4. Butylparaben...... 30 3.2.3.3. Polyethylene glycol 2.3. Solubility of hydroxybenzoic acid salt– derivative...... 107 water systems...... 33 3.2.4. Butylparaben...... 107 2.3.1. Singly substituted hydroxybenzoic 3.2.4.1. Alcohols...... 107 acid salts...... 33 3.2.4.2. Carbohydrate...... 108 2.3.1.1. 2-Hydroxybenzoic acid 3.2.4.3. Organic salt...... 108 salts...... 33 3.2.4.4. Polyethylene glycol 2.3.1.2. 3-Hydroxybenzoic acid derivatives...... 109 salts...... 36 3.2.5. Alkylparabens...... 110 2.3.1.3. 4-Hydroxybenzoic acid 3.2.5.1. Alcohol...... 110 salts...... 37 3.2.6. Benzylparaben...... 112 2.3.2. Dihydroxybenzoic acid salts...... 39 3.2.6.1. Alcohol...... 112 2.3.2.1. 2,3-Dihydroxybenzoic acid 3.2.6.2. Carbohydrate...... 113 salts...... 39 3.2.7. 2-Hydroxybenzoic acid salts...... 113 2.3.2.2. 2,4-Dihydroxybenzoic acid 3.2.7.1. Alcohol...... 113 salts...... 43 3.3. Hydroxybenzoic acid–water–inorganic 2.3.2.3. 2,5-Dihydroxybenzoic acid compound systems...... 116 salts...... 48 3.3.1. Salicylic acid...... 116 2.3.2.4. 2,6-Dihydroxybenzoic acid 3.3.1.1. Inorganic salts...... 116 salts...... 52 3.3.2. 3-Hydroxybenzoic acid...... 122 2.3.2.5. 3,4-Dihydroxybenzoic acid 3.3.3. 4-Hydroxybenzoic acid...... 122 salts...... 55 4. Hydroxybenzoic Acids and Parabens in 2.3.2.6. 3,5-Dihydroxybenzoic acid Multicomponent Aqueous Systems...... 123 salts...... 59 4.1. Hydroxybenzoic acid–water–organic 3. Hydroxybenzoic Acids, Parabens, and compound–inorganic compound systems... 123 Hydroxybenzoic Acid Salts in Ternary 4.1.1. 4-Hydroxybenzoic acid...... 123 Aqueous Systems...... 63 4.2. Hydroxybenzoic acid–water–inorganic 3.1. Hydroxybenzoic acid–water–organic compound ͑1͒–inorganic compound ͑2͒ compound systems...... 63 systems...... 123 3.1.1. Salicylic acid...... 63 4.2.1. 3-Hydroxybenzoic acid...... 123 3.1.1.1. Halides...... 63 4.2.2. 4-Hydroxybenzoic acid...... 124 3.1.1.2. Alcohols...... 64 4.3. Hydroxybenzoic acid and paraben–water– 3.1.1.3. Ketones and acids...... 69 urea–inorganic compound systems...... 124 3.1.1.4. Organic salts...... 70 4.3.1. Salicylic acid...... 124 3.1.1.5. Amides...... 79 4.3.2. 3-Hydroxybenzoic acid...... 126 3.1.1.6. Carbohydrates...... 80 4.3.3. 4-Hydroxybenzoic acid...... 127 3.1.1.7. Aromatic compounds...... 81 4.3.4. Methylparaben...... 127 3.1.1.8. Heterocyclic compounds. . . 87 4.4. Hydroxybenzoic acid and paraben–water– 3.1.2. 3-Hydroxybenzoic acid...... 91 urea–inorganic compound ͑1͒–inorganic 3.2. Parabens and hydroxybenzoic acid salt– compound ͑2͒ systems...... 128 water–organic compound systems...... 91 4.4.1. 4-Hydroxybenzoic acid...... 128 3.2.1. Methylparaben...... 91 4.4.2. Methylparaben...... 128 3.2.1.1. Alcohols...... 91 4.4.3. Ethylparaben...... 129 3.2.1.2. Amides...... 93 4.4.4. Propylparaben...... 129 3.2.1.3. Carbohydrate...... 100 4.4.5. Butylparaben...... 129 3.2.1.4. Polyethylene glycol 5. References...... 130 derivative...... 100 3.2.1.5. Aromatic compound...... 101 List of Tables 3.2.2. Ethylparaben...... 102 3.2.2.1. Alcohols...... 102 1. List of hydroxybenzoic acids, 3.2.2.2. Carbohydrate...... 103 hydroxybenzoates and hydroxybenzoic acid 3.2.2.3. Organic salt...... 103 salts...... 4

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2. List of compiled sheets for solutes in aqueous 1. Preface binary, ternary, and multicomponent systems. . . 4 3. Analytical methods of solutes in aqueous 1.1. Scope of the volume systems...... 5 This volume reviews experimentally determined solubility 4. Summary of experimental solubility data of data for well-defined binary, ternary, and multicomponent salicylic acid in water...... 5 5. Observed data and recommended values systems in which one component is a hydroxybenzoic acid, calculated according to Eq. ͑1͒ for salicylic hydroxybenzoate or hydroxybenzoic acid salt. The solutes acid in water...... 7 are as follows: hydroxybenzoic acid corresponds to 2-, 3-, 6. Summary of experimental solubility data of and 4-hydroxybenzoic acids. 4-hydroxybenzoic acid alkyl 3-hydroxybenzoic acid in water...... 11 ester ͑paraben͒ corresponds to methyl-, ethyl-, propyl-, 7. Observed data and recommended values butyl-, isobutyl-, hexyl- heptyl-, octyl-, decyl-, dodecyl-, and calculated according to Eq. ͑1͒ for 3-hydroxybenzoic acid in water...... 12 benzyl esters. Monohydroxybenzoic acid salts correspond to 8. Summary of experimental solubility data of lithium, sodium, potassium, rubidium, cesium, and silver 4-hydroxybenzoic acid in water...... 14 salts, and 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5- dihydroxyben- 9. Observed data and recommended values zoic acid salts correspond to cerium, dysprosium, erbium, ͑ ͒ calculated according to Eq. 1 for europium, gadolinium, holmium, neodymium, lanthanum, 4-hydroxybenzoic acid in water...... 15 lutetium, praseodymium, samarium, terbium, thulium, ytter- 10. Summary of experimental solubility data of methylparaben in water...... 18 bium, and yttrium salts. All of the solutes are in the solid 11. Observed data and recommended values state at room temperature. The list of the solutes is shown in calculated according to Eq. ͑1͒ for Table 1. The goal of the search is to include all published methylparaben in water...... 19 data for systems designated in the title. 12. Summary of experimental solubility data of Hydroxybenzoic acids and related compounds are impor- ethylparaben in water...... 24 tant substances closely related to daily life. Among the com- 13. Observed data and recommended values calculated according to Eq. ͑1͒ for piled sheets of the solutes, those for salicylic acid are the ethylparaben in water...... 24 most numerous. Salicylic acid is a phytohormone and it is a 14. Summary of experimental solubility data of key ingredient in many skin-care products for the treatment propylparaben in water...... 27 of acne, psoriasis, etc. For example, it has been used in 15. Observed data and recommended values shampoos because of its effect on skin cells. The solubilities calculated according to Eq. ͑1͒ for of the parabens which have a chemical structure of propylparaben in water...... 28 16. Summary of experimental solubility data of 4-hydroxybenzoic acid ester have been frequently reported. butylparaben in water...... 30 They are widely used as preservatives in the cosmetic, phar- 17. Observed data and recommended values maceutical, and food industries. They are used primarily for calculated according to Eq. ͑1͒ for their bacteriocidal and fungicidal properties and can be butylparaben in water...... 31 found in shampoo, shaving gels, toothpaste, etc. The parabens have been considered to be safe because of their low toxicity profile and their long history of safe use. However, a List of Figures few recent controversial studies have begun to challenge this 1. Fitting curve of Eq. ͑1͒ and the observed data view. At the present time, it is reported that parabens are 1–3 for salicylic acid in water...... 7 practically nontoxic. However, further research is neces- 2. Fitting curve of Eq. ͑1͒ and the observed data sary to determine the safety of parabens from the point of for 3-hydroxybenzoic acid in water...... 12 view of the precautionary principle. Therefore, it is important ͑ ͒ 3. Fitting curve of Eq. 1 and the observed data to give the solubility data concerning the hydroxybenzoic for 4-hydroxybenzoic acid in water...... 15 acid and the derivatives from the viewpoint of future human 4. Fitting curve of Eq. ͑1͒ and the observed data for methylparaben in water...... 19 health. The solubilities, as well as partition coefficients for 5. Fitting curve of Eq. ͑1͒ and the observed data parabens in water or aqueous solutions containing a surfac- for ethylparaben in water...... 24 tant at various temperatures, have been reported in several 6. Fitting curve of Eq. ͑1͒ and the observed data papers by Goto4–10 from the period 1977–1986 and the be- for propylparaben in water...... 28 havior of the parabens in pharmaceuticals and cosmetic bases 7. Fitting curve of Eq. ͑1͒ and the observed data has been thermodynamically studied. for butylparaben in water...... 31

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TABLE 1. List of hydroxybenzoic acids, hydroxybenzoates and hydroxyben- compilation. This volume includes solid-liquid equilibrium zoic acid salts of aqueous binary, ternary, and multicomponent systems. The list of binary, ternary, and multicomponent systems is shown Solute in Table 2. This is the result of an exhaustive search of the Hydroxybenzoic 2-Hydroxybenzoic acid ͑salicylic acid, 2HA͒, chemical literature using Chemical Abstracts. acid 3-hydroxybenzoic acid ͑3HA͒, 4-hydroxybenzoic acid ͑ ͒ 4HA TABLE 2. List of compiled sheets for solutes in aqueous binary, ternary, and HydroxybenzoateEster of hydroxybenzoic acid ͑paraben͒: methyl ester multicomponent systems ͑methylparaben, MP͒, ethyl ester ͑ethylparaben, EP͒, ͑ ͒ propyl ester propylparaben, PP , butyl ester Binary Ternary Multicomponent ͑ ͒ ͑ ͒ butylparaben, BP , isobutyl ester isobutylparaben , hexyl Solute systems systems systems ester ͑hexylparaben͒, heptyl ester ͑heptylparaben͒, octyl ester ͑octylparaben͒, decyl ester ͑decylparaben͒, dodecyl Hydroxybenzoic acid ͑HA͒ 21 72 10 ester ͑dodecylparaben͒, and benzyl ester ͑benzylparaben͒ Hydroxybenzoic acid ester ͑HAE͒ 31 58 5 Hydroxybenzoic 2-Hydroxybenzoic acid salt: lithium, sodium, potassium, Hydroxybenzoic acid salt ͑HAS͒ 102 6 0 acid salt rubidium, cesium, and silver salts 3-hydroxybenzoic acid salt: lithium, sodium, potassium, In some original sources, solubility data were reported as rubidium, and cesium salts incidental or ancillary information to other studies. If, for 4-hydroxybenzoic acid salt: lithium, sodium, potassium, this or other reasons, details concerning experimental meth- rubidium, cesium, and silver salts 2,3-hydroxybenzoic acid salt: cerium, dysprosium, ods, source and purity of materials, or estimated errors were erbium, europium, gadolinium, holmium, neodymium, brief or absent, correspondingly short entries appear in the lanthanum, lutetium, praseodymium, samarium, terbium, compilations, sometime with the note “No further details thulium, ytterbium, and yttrium salts were reported” or “not stated.” 2,4-dihydroxybenzoic acid salt: cerium, dysprosium, For convenience of comparison of experimental data, erbium, europium, gadolinium, holmium, neodymium, lanthanum, lutetium, praseodymium, samarium, terbium, compilers and the evaluators of this volume, as far as pos- thulium, and ytterbium salts sible, expressed all initial results in mass percent and mole 2,5-dihydroxybenzoic acid salt: cerium, dysprosium, fraction as well as in the units reported in the original source. erbium, europium, gadolinium, holmium, neodymium, Conversions, where they were made, are clearly attributed to lanthanum, lutetium, praseodymium, samarium, terbium, the compiler. Some units require numerical data for the den- thulium, and ytterbium salts 2,6-dihydroxybenzoic acid salt: dysprosium, erbium, sity of pure components and/or the mixtures. Deﬁnitions of gadolinium, holmium, lutetium, terbium, thulium, and mass percent and mole fraction as well as their relation to ytterbium salts other units of solubility are given in the Introduction to the 3,4-dihydroxybenzoic acid salt: cerium, dysprosium, Solubility Data Series.11 erbium, europium, gadolinium, holmium, neodymium, lanthanum, lutetium, praseodymium, samarium, terbium, 1.2. Experimental methods thulium, ytterbium, and yttrium salts 3,5-dihydroxybenzoic acid salt: cerium, dysprosium, Most solubility measurements of binary, ternary, and mul- erbium, europium, gadolinium, holmium, neodymium, ticomponent systems containing each solute have been made lanthanum, lutetium, praseodymium, samarium, terbium, thulium, and ytterbium salts from 260.3 to 486.2 K at atmospheric pressure. Samples of liquid phases at equilibrium are analyzed by various meth- In Part I of this volume, all of the systems are aqueous ods. The solubility measurements of hydroxybenzoic acids solutions. However, the ternary or multicomponent systems for binary, ternary, and multicomponent systems are mainly include organic substances of various classes ͑hydrocarbons carried out by titration in which the sample solution was ͑ ͒ of several structural types, halogenated hydrocarbons, alco- titrated with alkali solution such as NaOH or Ba OH 2 solu- hols, acids, ethers esters, amides, and surfactants͒ or inor- tion using p-nitrophenol, phenolphthalein, or Congo Red as ganic substances. an indicator. The solubility measurement of hydroxybenzoic An exhaustive search of the chemical literature published acid salts in binary, ternary, and multicomponent systems prior to 2001 found solubility data for eight categories of was carried out mainly by gravimetry and the synthetic systems, as shown in Table 2. From these, 307 compilation method. The basic approach to solubility measurement of sheets were prepared. Most compilations present the solubil- hydroxybenzoates for binary, ternary, and multicomponent ity data for one system as reported in one publication. For systems is UV spectroscopy, but gravimetry is used in lim- some original publications, which reported very limited data ited systems. Table 3 lists various methods for measurement for several systems, those data are grouped into a single of the solubilities.

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TABLE 3. Analytical methods of solutes in aqueous systems

Multicomponent Binary system Ternary system system Total Methoda HAb HAEc HASd HA HAE HAS HA HAE numbera

Spectroscopy 6 27 31 2 53 0 10 5 134 Titration 6 0 0 46 1 0 0 0 53 Gravimetry 3 0 53 9 5 5 0 0 75 Synthetic method 4 0 15 6 0 0 0 0 25 Other methode 01 3101 0 0 6 aThe total number of sheets does not correspond with the sum of the different methods because some sheets contain plural analytical methods and some sheets for references whose methods are not described clearly are not counted. bHA: Hydroxybenzoic acid. cHAE: Hydroxybenzoic acid ester. dHAS: Hydroxybenzoic acid salt. eOther methods include thermometry, and measurement of radioisotopes, potential difference, HPLC, and vapor pressure.

System pressure at the solution temperature is seldom re- The solubilities calculated by the proposed equation are ported because it is assumed that the effect of pressure is presented in the figures and tables, whose values are recom- minor. Sources of error in these methods include gravita- mended. tional effects and impurities in materials whose solubilities A complete guide to the preparation and use of compila- are determined. tions and evaluations for the IUPAC-NIST Solubility Data Series can be found in the article11 jointly published by 1.3. Procedure used in critical evaluation IUPAC and NIST. These procedures were applied to all the data sources4–10,15–84 compiled here. A critical evaluation was prepared for each system for Of particular interest for the present volume are the un- which multiple independent reports of solubility are avail- common use of the symbols ␥ for mass concentration and ␸ able. In evaluating the available data, the evaluators have for volume fraction. These symbols, defined in Ref. 11, are considered the data quality of individual original sources to often found in the pharmaceutical literature, particularly in the extent that can be established from the content ͑and the older literature. omissions͒ of those reports and by comparing the results obtained independently in more than one laboratory. Several 2. Hydroxybenzoic Acids, Parabens, and aspects of the solubility data have been considered: purity of Hydroxybenzoic Acid Salts in Binary substances, date of experiment, experience of the research- er͑s͒, and previous publications. Aqueous Systems Data are recommended if the results of independent 2.1. Hydroxybenzoic acid–water systems groups closely agreed with each other and the evaluator has 2.1.1. Critical evaluation of the solubility of no doubt of the adequacy of the experimental and computa- hydroxybenzoic acids tional procedures used. Data determined by an inadequate or ill-defined method are rejected. 2.1.1.1. Salicylic acid „2-hydroxybenzoic acid… Where two or more reliable compilations were found for a system, a critical evaluation was carried out. This was pos- Components: Evaluators: sible for only seven systems of hydroxybenzoic acid ͑sali- ͑1͒ Benzoic acid, 2-hydroxy- Ayako Goto, University of cylic acid, 3-, and 4-hydroxybenzoic acid͒ and parabens ͑salicylic acid; o-hydroxybenzoic Shizuoka, Shizuoka, Japan; ͒ ͓ ͔ ͑methyl-, ethyl-, propyl-, and butylparabens͒ in water in the acid ;C7H6O3; 69-72-7 Rensuke Goto, University of ͑ ͒ ͓ ͔ 2 Water; H2O 7732-18-5 Shizuoka, Shizuoka, Japan; range from 273.2 to 474.5 K. Hiroshi Miyamoto, Niigata Data for the solubility of the hydroxybenzoic acids and the University, Niigata, Japan; parabens in water can be treated as a function of absolute Hiroshi Fukuda, Kitasato temperature. Data for the solubility of the hydroxybenzoic University, Tokyo, Japan acids and the alkyl esters were fitted to Eq. ͑1͒,12–14 / ͑ ͒ Critical Evaluation ln x1 = A T + B ln T + C. 1 TABLE 4. Summary of experimental solubility data of salicylic acid in water The equation parameters are presented in the critical / 2 / −3 2 / −1 4 evaluations and were statistically calculated by the least- T K10c1 mol dm 10 m1 mol kg 10 x1 Analytical method Reference squares method so that the smoothing equation gives smaller a ͑ ͑ ͒ ͒ 273.2 0.670 1.20 Titration Ba OH 2 15 standard deviations than any other tested equation, such as 273.2 0.899 1.62a Gravimetry 16 the equation 278.2 0.935 1.68a Gravimetry 16 / ͑ ͒ 283.15 1.99 Titration ͑NaOH͒ 12 ln x1 = A T + C. 2

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TABLE 4. Summary of experimental solubility data of salicylic acid in TABLE 4. Summary of experimental solubility data of salicylic acid in water—Continued water—Continued

/ 2 / −3 2 / −1 4 / 2 / −3 2 / −1 4 T K10c1 mol dm 10 m1 mol kg 10 x1 Analytical method Reference T K10c1 mol dm 10 m1 mol kg 10 x1 Analytical method Reference

283.2 0.979 1.76a Gravimetry 16 313.2 3.02 5.44a Gravimetry 16 a ͑ ͑ ͒ ͒ a ͑ ͑ ͒ ͒ 283.2 0.950 1.71 Titration Ba OH 2 17 313.2 2.86 5.17 Titration Ba OH 2 17 a ͑ ͑ ͒ ͒ ͑ ͒ 285.3 1.01 1.82 Titration Ba OH 2 15 317.15 5.73 Titration NaOH 12 a ͑ ͑ ͒ ͒ 287.7 1.21 No information 18 and 317.2 6.00 Titration Ba OH 2 17 19 318.15 6.77 Titration ͑NaOH͒ 12 a 288.2 1.33 2.40 Gravimetry 16 318.2 3.56 6.41a Gravimetry 16 a 293.2 1.45 2.61 Gravimetry 16 318.2 2.75 Gravimetry 36 a ͑ ͑ ͒ ͒ 293.2 1.33 2.40 Titration Ba OH 2 17 320.15 6.72 Titration ͑NaOH͒ 12 a a ͑ ͑ ͒ ͒ 293.2 1.60 2.90 Titration and 20 321.8 3.70 6.66 Titration Ba OH 2 15 Gravimetry 323.15 8.43 Titration ͑NaOH͒ 12 a 293.2 1.40 2.50 Titration ͑NaOH͒ 21 323.2 4.65 8.37a Gravimetry 15 293.3 1.32 Titration ͑KOH͒ 22 323.2 7.30a Synthetic method 41 296.2 1.48 2.67a Titration ͑Ba͑OH͒ ͒ 15 a ͑ ͑ ͒ ͒ 2 323.2 4.29 7.76 Titration Ba OH 2 17 ͑ ͑ ͒ ͒ 298.04 1.60 2.88 Titration Ba OH 2 23 324.15 7.85 Titration ͑NaOH͒ 12 298.15 3.33 Titration ͑NaOH͒ 12 325.15 8.47 Titration ͑NaOH͒ 12 a 298.2 1.60 2.90 Titration ͑alkali 24 327.15 9.34 Titration ͑NaOH͒ 12 ͒ solution 328.15 9.65 Titration ͑NaOH͒ 12 298.2 1.60 2.90 Gravimetry 25 328.2 5.43 9.77a Gravimetry 16 298.2 1.64 Titration ͑NaOH͒ 26 a ͑ ͑ ͒ ͒ 329.2 4.98 8.96 Titration Ba OH 2 15 298.2 1.63 Gravimetry 27 329.2 9.41a Synthetic method 41 ͑ ͑ ͒ ͒ 298.2 1.63 Titration Ba OH 2 27 330.65 11.1 Titration ͑NaOH͒ 12 a 298.2 1.80 3.24 Gravimetry 16 a ͑ ͑ ͒ ͒ 331.2 11.1 Titration Ba OH 2 17 298.2 1.61 Gravimetry 28 333.2 6.58 11.8a Gravimetry 16 298.2 1.62 Gravimetry 29 333.2 6.26 11.4a Titration ͑Ba͑OH͒ ͒ 17 ͑ ͑ ͒ ͒ 2 298.2 1.60 Titration Ba OH 2 30 334.65 13.1 Titration ͑NaOH͒ 12 298.2 1.53 Electrometry 31 a ͑ ͑ ͒ ͒ 336.2 13 Titration Ba OH 2 17 298.2 1.79 Not stated 18 and a ͑ ͑ ͒ ͒ 337.2 7.21 13.0 Titration Ba OH 2 15 19 338.2 8.01 14.4a Gravimetry 16 298.2 1.90 Not stated 32 339.15 14.9 Titration ͑NaOH͒ 12 ͑ 298.2 1.61 Titration alkali 33 339.2 8.47 15.2a Titration ͑Ba͑OH͒ ͒ 15 solution͒ 2 342.0 17a Titration ͑Ba͑OH͒ ͒ 17 298.2 1.62 Titration ͑NaOH͒ 34 2 343.2 10.1 18.1a Gravimetry 16 298.3 1.60 Titration ͑NaOH͒ 35 348.2 12.7 22.8a Volumetry 15 298.7 1.491 Spectrophotometry 36 ͑Ba͑OH͒ ͒ ͑ ͒ 2 299.6 1.71 Titration NaOH 37 348.2 12.9 23.2a Gravimetry 16 301.0 1.80 Not stated 32 353.2 16.4 29.4a Gravimetry 16 301.2 3.12 Not stated 38 353.2 26.9a Synthetic method 41 a ͑ ͑ ͒ ͒ 301.3 1.79 3.22 Titration Ba OH 2 15 358.2 20.8 37.3a Gravimetry 16 301.4 1.78 Not stated 32 363.2 28.1 50.4a Gravimetry 16 301.5 1.78 Not stated 32 368.2 38.5 68.9a Gravimetry 16 302.3 1.85 Not stated 32 373.2 58.8 104.7a Gravimetry 16 303.2 2.16 3.89a Gravimetry 16 303.2 1.89 3.41a Titration ͑Ba͑OH͒ ͒ 17 a / −1 2 The mole-fraction solubilities were calculated based upon m1 mol kg or 303.2 2.2 4.0a Titration, 20 w1. Gravimetry Solubilities of salicylic acid in water were reported in 28 303.2 1.99 No information 18 and 19 publications. The measurements were carried out from 303.2 2.14 3.85a Spectrophotometry 39 273.2 to 373.2 K. The solubilities of salicylic acid in water 303.7 2.13 Not stated 32 are shown in Table 4, in which mole fraction and molar 303.8 2.20 Titration ͑NaOH͒ 40 307.15 4.41 Titration ͑NaOH͒ 12 concentration are used as units. The measurement was car- a ͑ ͑ ͒ ͒ 307.6 2.21 3.98 Titration Ba OH 2 15 ried out mainly by titration and gravimetry, as shown in 307.97 2.324 4.18 Gravimetry, 23 Table 4. Volumetry ͑ ͑ ͒ ͒ Data for the solubility of salicylic acid in water ex- Ba OH 2 308.2 2.55 4.59a Gravimetry 16 pressed in mole fraction can be treated as a function of ab- 310.2 1.81 Spectrophotometry 36 solute temperature. They were ﬁtted to Eqs. ͑1͒ and ͑2͒ given a ͑ ͑ ͒ ͒ 311.9 2.60 4.68 Titration Ba OH 2 15

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TABLE 5. Observed data and recommended values calculated according to Eq. ͑1͒ for salicylic acid in water

/ 4 ͑ ͒ 4 ͑ ͒ T K10x1 obs 10 x1 rec

273.2 1.62 1.48 278.2 1.68 1.66 283.2 1.76 1.88 285.3 1.82 1.99 288.2 2.4 2.16 293.2 2.5 2.52 296.2 2.67 2.77 298.2 2.9 2.96 301.2 3.12 3.28 303.2 3.41 3.52 FIG. 1. Fitting curve of Eq. ͑1͒ and the observed data for salicylic acid in water. 307.15 4.41 4.07 308.2 4.59 4.23 311.9 4.68 4.87 in Sec. 1.3. The data points very closely agree with Eq. ͑1͒ in 318.2 6.41 6.25 320.15 6.72 6.77 the whole range of temperature, as shown in Fig. 1, but they 321.8 6.66 7.25 ͑ ͒ deviate from Eq. 2 in the range of higher and lower tem- 323.2 7.76 7.69 peratures. The equation parameters were derived by multiple 328.2 9.77 9.52 regression analysis using SPSS based on Eq. ͑1͒, with the 329.2 9.41 9.95 331.2 11.1 10.86 following results: 333.2 11.8 11.87 Multiple correlation coefficient: 0.997 336.2 13.0 13.59 Sample size: 68 337.2 13.0 14.22 p-value ͑F test͒: 0.000 338.2 14.4 14.89 Ϯ Ϯ 339.2 15.2 15.59 Constants: A=13810 890, B=56.35 2.81, C= 342 17.0 17.75 −375.5Ϯ19.0 343.2 18.1 18.77 White circles in Fig. 1 represent the observed data and 348.2 23.2 23.80 the black line corresponds to calculated values according to 353.2 29.4 30.31 358.2 37.3 38.77 ͑ ͒ ͑ / ͒ Eq. 1 ln x1 =13810 T+56.35 ln T−375.5 . The observed 363.2 50.4 49.79 data fit closely with the calculated line in the range of 368.2 68.9 64.19 273.2–373.2 K, with the multiple correlation coefficient of 373.2 104.7 83.04 0.997, as shown in Fig. 1. Therefore, the calculated value at each measured temperature is reasonably considered as a rec- Components: Original Measurements: ommended value in the whole range of temperature. ͑1͒ Benzoic acid, 2-hydroxy- 15J. Walker and J. K. Wood, J. ͑o-hydroxybenzoic acid; salicylic Chem. Soc. Trans. 73,618 Table 5 shows typical observed data in the range of ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1898 . ͑ ͒ ͓ ͔ 273.2–373.2 K selected from among the sources in Table 4, 2 Water; H2O; 7732-18-5 ͑ ͒ and the recommended values calculated from Eq. 1 at each Variables: Prepared by: temperature. t/ °C=0.0 to 75.0 A. Goto and H. Miyamoto

Solubility of salicylic acid in water

Temperature Observed solubility Calculated solubility

͑ ͒a / −1 ͑ ͒b / −1 S author 100w1 100m1 mol kg S author 100m1 mol kg t/ °C g͑1͒/100 g͑2͒ ͑compiler͒ ͑compiler͒ g͑1͒/100 g͑2͒ ͑compiler͒

0.0 0.092 0.092 0.67 0.090 0.65 12.1 0.1395 0.139 1.01 0.139 1.01 23.0 0.204 0.204 1.48 0.205 1.48 28.1 0.247 0.246 1.79 0.246 1.78 34.4 0.305 0.304 2.21 0.309 2.24 38.7 0.359 0.358 2.60 0.360 2.61 48.6 0.511 0.508 3.70 0.513 3.71

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Solubility of salicylic acid in water

Temperature Observed solubility Calculated solubility

͑ ͒a / −1 ͑ ͒b / −1 S author 100w1 100m1 mol kg S author 100m1 mol kg t/ °C g͑1͒/100 g͑2͒ ͑compiler͒ ͑compiler͒ g͑1͒/100 g͑2͒ ͑compiler͒

56.0 0.688 0.683 4.98 0.669 4.84 64.0 0.996 0.986 7.21 — — 66.0 1.17 1.16 8.47 — — 75.0 1.76 1.73 12.7 — —

aIn the original paper, the solubility was given as grams per hundred grams of solvent. b ͑ ͒ The solubility was calculated from the equation log10 S=0.015 56t−1.0458 reported by the author, where the solubility S symbol given in the original paper was given as grams per hundred grams of solvent and t is the temperature in degrees Centigrade.

Auxiliary Information Solubility of salicylic acid in water

Method/Apparatus/Procedure: Temperature Solubility Both saturation and supersaturation methods were used to obtain the / −1 saturated solutions. The solutions were usually agitated by stirrers driven 100w1 100m1 mol kg by a small turbine, but at the higher temperatures, equilibrium was t/ °C Original dataa ͑compiler͒ ͑compiler͒ reached with only occasional agitation by hand. The salicylic acid solutions obtained were titrated directly with barium hydroxide solution 75 17.55 1.755 12.93 using Congo Red as an indicator, after previously diluting with water. The 80 22.09 2.209 16.35 barium hydroxide solution was standardized with pure succinic acid using 85 27.92 2.792 20.79 phenolphthalein as an indicator. 90 37.35 3.735 28.09 95 50.48 5.048 38.49 Source and Purity of Materials: 100 75.07 7.507 58.76 No information was given. aIn the original paper, the solubility was given as grams per 1000 grams of Estimated Errors: solution. Nothing speciﬁed. Auxiliary Information

Components: Original Measurements: Method/Apparatus/Procedure: ͑1͒ Benzoic acid, 2-hydroxy- 16E. Savarro, Atti accad. sci. The solubility of salicylic acid in water was determined in Pawlewski’s ͑o-hydroxybenzoic acid; salicylic Torino 48, 948 ͑1914͓͒Chem. apparatus ͓B. Pawlewski, Ber. Dtsch. Chem. Ges. 32, 1040 ͑1899͔͒. The ͒ ͓ ͔ ͑ ͔͒ salicylic acid content was determined by using the standardized sodium acid ;C7H6O3; 69-72-7 Abs. 8, 340 1914 . ͑ ͒ ͓ ͔ hydroxide solution. The water and salicylic acid were placed in the test 2 Water; H2O; 7732-18-5 tube. The tube was equipped with a condenser and a siphon glass tube Variables: Prepared by: and connected with a weighing bottle equipped with a condenser. The t/ °C=0 to 100 A. Goto and H. Miyamoto apparatus was placed into a large thermostated glass beaker to mix the water and salicylic acid, and air was bubbled through the mixture. After equilibrium was established, the saturated solution in the tube was filtered Solubility of salicylic acid in water into the weighing tube through the siphon tube equipped with a cotton wool filter. The apparatus was removed from the large beaker, cooled Temperature Solubility and/or dried, and the bottle was weighed. Salicylic acid was determined gravimetrically after evaporation of the solvent. / −1 100w1 100m1 mol kg a t/ °C Original data ͑compiler͒ ͑compiler͒ Source and Purity of Materials: Salicylic acid was recrystallized before use. 0 1.24 0.124 0.899 5 1.29 0.129 0.935 Estimated Errors: 10 1.35 0.135 0.979 Solubility: precision of Ϯ1.5%. 15 1.84 0.184 1.33 Temperature: nothing specified. 20 2.00 0.200 1.45 25 2.48 0.248 1.80 30 2.98 0.298 2.16 Components: Original Measurements: 35 3.51 0.351 2.55 ͑1͒ Benzoic acid, 2-hydroxy- 41S.V. Sidgwick and E.K. 40 4.16 0.416 3.02 ͑o-hydroxybenzoic acid; salicylic Embank, J. Chem. Soc. 1921, ͒ ͓ ͔ 45 4.89 0.489 3.56 acid ;C7H6O3: 69-72-7 979. ͑ ͒ ͓ ͔ 50 6.38 0.638 4.65 2 Water; H2O; 7732-18-5 55 7.44 0.744 5.43 Variables: Prepared by: 60 9.00 0.900 6.58 t/ °C=50.0 to 159.0 A. Goto and H. Miyamoto 65 10.94 1.094 8.008 70 13.75 1.370 10.06

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Solubility of salicylic acid in water Solubility of salicylic acid in water

Temperaturea Solubility Temperature Solubility

/ / 2 / −1 t °C t °C 100x1 100x1 10 c1 mol kg ͑ ͒ ͑ ͒ ͑ ͒ / ͑ ͒ ͑ ͒ solid liquid 100w1 compiler t °C 100w1 compiler compiler

159.0 100.0 100.0 10.0 0.131 0.0171 0.950 131.8 89.75 53.32 20.0 0.184 0.024 1.33 119.5 80.00 34.28 30.0 0.261 0.0341 1.89 109.5 67.0 65.40 19.78 40.0 0.395 0.0517 2.86 107.2 86.4 48.18 10.82 50.0 0.592 0.0776 4.29 106.7 89.1 34.02 6.30 60.0 0.864 0.114 6.0 105.6 87.2 16.82 2.57 101.4 77.3 8.02 1.12 Auxiliary Information 97.9 5.27 0.720 80.0 2.026 0.2690 Method/Apparatus/Procedure: 56.0 0.717 0.0941 The mixtures of salicylic acid and water were stirred in a thermostat. Both 50.0 0.557 0.0730 supersaturation and undersaturation methods were used. When equilibrium had been attained, the solution was sucked off through a side tube with aCritical solution temperature; 89.5 °C filter into a stoppered flask and weighed, transferred to a measuring flask, and made up to a known volume. Salicylic acid was directly estimated Two transition points of temperature ͑solid͒ and tem- with barium hydroxide solution using p-nitrophenol as an indicator. perature ͑liquid͒ were observed in the limited range, as Source and Purity of Materials: shown in the above table, in which ͑solid͒ and ͑liquid͒ were Commercial salicylic acid was recrystallized from water four times. The indicated by the authors. These phenomena were explained physiologically pure salicylic acid was dissolved in a hot mixture of phenol and water, and the solution was slowly cooled. After the product by the authors that the solution, supersaturated with respect was recrystallized twice, the m.p. of the purified product was 158.7 °C. to the solid, separates into two liquid phases before crystal- When allowance was made for stem distillation, the m.p. was increased to 160.4 °C. lization begins. Temperature ͑solid͒ corresponds to that for transition from liquid to two phases, and temperature ͑liquid͒ Estimated Errors: Nothing specified. corresponds to that for transition from two phases to solid.

Auxiliary Information Components: Original Measurements: Method/Apparatus/Procedure: ͑1͒ Benzoic acid, 2-hydroxy- 18S.S. Doosaj and W.V. Bhagwat, The solubility was determined synthetically. Weighed quantities of the ͑o-hydroxybenzoic acid; salicylic J. Indian Chem. Soc. 10,225 ͒ ͓ ͔ ͑ ͒ acid and the solvent were enclosed in bulbs, which were sealed and acid ;C7H6O3; 69-72-7 1933 ͑ ͒ ͓ ͔ 19 heated in a suitable bath. The thermometers had been compared with a 2 Water; H2O; 7732-18-5 W.V. Bhagwat and S.S. Doosaj, standard instrument, and all readings were corrected. J. Indian Chem. Soc. 10,477 ͑1933͒. Source and Purity of Materials: The preparation and puriﬁcation methods were described elsewhere ͓J. Variables: Prepared by: Walker and J.K. Wood, J. Chem. Soc. 117,40͑1920͔͒. The m.p. of t/ °C=14.5, 25.0, and 30.0 A. Goto and H. Miyamoto salicylic acid was 89.5 °C.

Estimated Errors: Solubility of salicylic acid in water Nothing speciﬁed. Temperature Solubility

2 / −3 10 c1 mol dm Components: Original Measurements: / ␥ / −3 ͑ ͒ t °C 1 gdm compiler ͑1͒ Benzoic acid, 2-hydroxy- 17C.R. Bailey, J. Chem. Soc. ͑o-hydroxybenzoic acid; salicylic Trans. 126, 1951 ͑1925͒. 14.5 1.667 1.207 ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 25.0 2.478 1.794 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 30.0 2.743 1.986 Variables: Prepared by: t/ °C=10.0 to 60.0 A. Goto and H. Miyamoto

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Auxiliary Information Solubility of salicylic acid in water

Method/Apparatus/Procedure: Temperature Solubilitya No information was given. 2 / −3 10 c1 mol dm / ␥ / −3 ͑ ͒ Source and Purity of Materials: t °C 1 gdm author No information was given. 25 2.581 1.896 Estimated Errors: 27.8 2.479 1.795 Nothing speciﬁed. 28.2 2.461 1.782 28.3 2.461 1.782 29.1 2.551 1.847 Components: Original Measurements: 30.5 2.935 2.125 ͑1͒ Benzoic acid, 2-hydroxy- 38P.G. Desai and A.M. Patel, J. a␥ ͑o-hydroxybenzoic acid; salicylic Indian Chem. Soc. 12, 131 1 value was described by H. Stephen and T. Stephen, Solubilities of Inor- ͒ ͓ ͔ ͑ ͒ ͑ acid ;C7H6O3; 69-72-7 1935 . ganic and Organic Compounds, Vol. 2 part 1 Pergamon Press, Oxford, ͑ ͒ ͓ ͔ ͒ 2 Water; H2O; 7732-18-58 1979 , p. 194. In the original paper, c1 was given as “Normality” units.

Variables: Prepared by: Auxiliary Information t/ °C=28 A. Goto and H. Miyamoto Method/Apparatus/Procedure: No information was given. Solubility of salicylic acid in water Source and Purity of Materials: Temperature Solubility No information was given.

/ 4 t °C 10 x1 Estimated Errors: Nothing speciﬁed. 28 3.118

Auxiliary Information Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 36D.M. Altwein, J.N. Delgado, Method/Apparatus/Procedure: ͑o-hydroxybenzoic acid; salicylic and F.P. Cosgrove, J. Pharm. Sci. Water was saturated with salicylic acid in a series of flasks, which were acid͒;CH O ; ͓69-72-7͔ 54, 603 ͑1965͒. kept revolving on a wheel in an air thermostat at 28 °C for 48 h. In order 6 7 3 ͑2͒ Water; H O; ͓7732-18-5͔ to avoid any error due to the absorption of the solute by the filter paper, a 2 fresh saturated solution was filtered through it before the solution used for Variables: Prepared by: the estimation of the acid was passed through. A suitable amount of the t/ °C=25.5, 37.0, and 45.0 A. Goto and H. Miyamoto filtrate was titrated against barium hydroxide solution using phenolphthalein as an indicator. The stock solution of barium hydroxide was titrated against a standard solution of succinic acid. Solubility of salicylic acid in water

Source and Purity of Materials: Temperature Solubility Water whose conductivity was checked was used throughout the work. / 2 / −3 Salicylic acid was twice recrystallized. t °C 10 c1 mol dm

Estimated Errors: 25.5 1.491 37.0 1.810 Solubility: the error was less than 0.5%. 45.0 2.751 Temperature: nothing speciﬁed.

Auxiliary Information Components: Original Measurements: Method/Apparatus/Procedure: ͑1͒ Benzoic acid, 2-hydroxy- 32W.V. Bhagwat, J. Indian Chem. ͑ ͑o-hydroxybenzoic acid; salicylic Soc. 16, 235 ͑1939͒. Definite quantities of salicylic acid 2 g at 25.5 and 37.0 °C, 2 and 2.5 g ͒ ͓ ͔ at 45.0 °C͒ and 50 ml of water were placed in 100 ml volumetric flasks. acid ;C7H6O3; 69-72-7 ͑ ͒ ͓ ͔ The flasks were stoppered and the mixtures were shaken in a thermostat 2 Water; H2O; 7732-18-5 for 12 h at 25.5, 37.0, and 45.0 °C. 1 ml volumetric pipettes equipped Variables: Prepared by: with twine were used. Aliquot quantities were removed from the t/ °C=25–30.5 A. Goto and H. Miyamoto dissolution fluids, diluted to the proper concentration, and assayed spectrophotometrically for the amount of acid at 236 m␮. All of the samples and controls were run in triplicate.

Source and Purity of Materials: Salicylic acid was of Baker analyzed reagent. The melting point of the acid was 159 °C.

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Estimated Errors: Auxiliary Information Solubility: nothing speciﬁed. Temperature: precision Ϯ0.2 °C. Method/Apparatus/Procedure: The solubility measurements were performed as described by A. Apelblat and E. Manzurola, J. Chem. Thermodyn. 19, 317 ͑1987͒. Suspended in excess, solid was dissolved in distilled water by stirring for 10 h in Components: Original Measurements: double-wall tubes thermostated by circulating water. The stirring was ͑ ͒ 12 1 Benzoic acid, 2-hydroxy- A. Apelblat and E. Manzurola, followed by gravitational settling overnight. The weighed samples of ͑ o-hydroxybenzoic acid; salicylic J. Chem. Thermodyn. 21, 1005 saturated solutions were titrated with solutions of NaOH, standardized ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1989 . with potassium hydrogen phthalate. Phenolphthalein was used as an ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 indicator.

Variables: Prepared by: Source and Purity of Materials: / T K=283.15–339.15 A. Goto, R. Goto, and H. Salicylic acid was obtained from Sigma. Sodium hydroxide and potassium Miyamoto hydrogen phthalate were obtained from Merck.

Solubility of salicylic acid in water Estimated Errors: Solubility: nothing speciﬁed. Ϯ Temperature Solubility Temperature: precision 0.01 K.

/ 3 T K10x1

283.15 0.1998 298.15 0.3333 307.15 0.4411 317.15 0.5725 2.1.1.2. 3-Hydroxybenzoic acid 318.15 0.6772 320.15 0.6720 Components: Evaluators: 323.15 0.7425 ͑1͒ Benzoic acid, 3-hydroxy- Ayako Goto, University of 324.15 0.7854 ͑m-hydroxybenzoic acid͒; Shizuoka, Shizuoka, Japan; ͓ ͔ 325.15 0.8474 C7H6O3; 99-06-9 Rensuke Goto, University of ͑ ͒ ͓ ͔ 327.15 0.9339 2 Water; H2O 7732-18-5 Shizuoka, Shizuoka, Japan; 328.15 0.9645 Hiroshi Miyamoto, Niigata 330.65 1.108 University, Niigata, Japan; 334.65 1.306 Hiroshi Fukuda, Kitazato 339.15 1.490 University, Tokyo, Japan

Critical Evaluation TABLE 6. Summary of experimental solubility data of 3-hydroxybenzoic acid in water

/ 2 / −3 2 / −1 4 T K10c1 mol dm 10 m1 mol kg 10 x1 Analytical method Reference a ͑ ͑ ͒ ͒ 286.5 0.048 4 0.0871 Titration Ba OH 2 15 288.2 0.510 0.0913a Gravimetry 16 a ͑ ͑ ͒ ͒ 292.0 0.061 0 0.1110 Titration Ba OH 2 15 a ͑ ͑ ͒ ͒ 297.5 0.076 3 0.137 Titration Ba OH 2 15 298.2 0.0531 Titration ͑alkali solution͒ 33 303.2 0.050 6 0.0910a Titration ͑alkali solution͒ 39 a ͑ ͑ ͒ ͒ 304.1 0.099 91 0.180 Titration Ba OH 2 15 a ͑ ͑ ͒ ͒ 309.4 0.129 0.233 Titration Ba OH 2 15 323.2 0.302 0.519a Gravimetry 16 a ͑ ͑ ͒ ͒ 324.2 0.229 0.411 Titration Ba OH 2 15 342.2 0.471 0.841a Synthetic method 41 352.8 0.791 1.40a Synthetic method 41 357.8 1.25 2.199a Synthetic method 41 366.5 2.44 4.214a Synthetic method 41 371.5 3.71 6.257a Synthetic method 41 383.0 7.20 11.5a Synthetic method 41 407.2 17.6 24.0a Synthetic method 41 474.5 — 100.0a Synthetic method 41

a / −1 The mole-fraction solubilities were calculated based upon m1 mol kg or w1.

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TABLE 7. Observed data and recommended values calculated according to Eq. ͑1͒ for 3-hydroxybenzoic acid in water—Continued

/ 4 ͑ ͒ 4 ͑ ͒ T K10x1 obs 10 x1 rec

309.4 0.233 0.1991 323.2 0.519 0.3701 324.2 0.411 0.3883 342.2 0.841 0.981 352.8 1.40 1.775 357.8 2.199 2.373 366.5 4.214 3.986 371.5 6.257 5.410 FIG. 2. Fitting curve of Eq. ͑1͒ and the observed data for 3-hydroxybenzoic acid in water. Components: Original Measurements: The critical evaluation was carried out as described in ͑1͒ Benzoic acid, 3-hydroxy- 15J. Walker and J.K. Wood, J. ͑m-hydroxybenzoic acid͒; Chem. Soc. Trans. 73,618 Sec. 2.1.1.1 for salicylic acid in water: ͓ ͔ ͑ ͒ C7H6O3; 99-06-9 1898 . The number of publications: 5 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 The range of temperature: 286.5–474.5 K The unit: mass percent, mole fraction, and molar concen- Variables: Prepared by: tration t/ °C=13.3–51.0 A. Goto and H. Miyamoto Analytical methods: synthetic method, and titration Data in Table 6 for the solubility of 3-hydroxybenzoic Solubility of 3-hydroxybenzoic acid in water acid in water expressed by mole fraction were fitted to Eqs. a,b c ͑1͒ and ͑2͒ given in Sec. 1.3. The data points very closely Temperature Observed solubility Calculated solubility ͑ ͒ / −1 / −1 agree with Eq. 1 in the range from 286.5 to 371.5 K, as Original 100w1 m1 mol kg 100S m1 mol kg shown in Fig. 2, where the data above 373.2 K were ex- t/ °C dataa ͑compiler͒ ͑compiler͒ ͑compiler͒ ͑compiler͒ cluded to compare with the result of salicylic acid, but they 13.3 0.668 0.554 0.048 4 0.671 0.048 6 deviate from Eq. ͑2͒ in the range of higher and lower tem- ͑ ͒ 18.8 0.843 0.836 0.061 0 0.842 0.061 0 perature. Multiple regression analysis according to Eq. 1 24.3 1.054 1.043 0.076 31 1.057 0.076 53 yielded the following results: 30.9 1.380 1.361 0.099 91 1.388 0.100 5 Multiple correlation coefficient: 0.990 36.2 1.787 1.756 0.129 4 1.727 0.125 0 Sample size: 14 51.0 3.167 3.070 0.229 3 3.180 0.230 2 p-value ͑F test͒: 0.000 a Constants: A=18 410Ϯ6794, B=72.43Ϯ20.91, C= In the original paper, the solubility was given as grams per hundred grams of water. −485.7Ϯ141.9 b The w1 value was calculated by the compiler. White circles in Fig. 2 represent the observed data and c The solubility is calculated from the equation log10 S=0.017 93t−0.4118, the black line corresponds to calculated values according to where S ͑symbol given in the original paper͒ is the solubility by weight and ͑ ͒ ͑ / ͒ Eq. 1 ln x1 =18 410 T+72.43 ln T−485.7 . The observed t is the temperature in degrees Centigrade. data fit closely with the calculated line in the range of Auxiliary Information 286.5–371.5 K, with the multiple correlation coefficient of 0.990, as shown in Fig. 2. Therefore, the calculated value at Method/Apparatus/Procedure: each measured temperature is reasonably considered as a rec- The experimental detail is given in the compilation of Ref. 15 for the ommended value in the whole range of temperature. salicylic acid–water system in Sec. 2.1.1.1. Table 7 shows typical observed data in the range of Source and Purity of Materials: 286.5–371.5 K and the recommended values calculated No information was given. from Eq. ͑1͒ at each temperature. Estimated Errors:

TABLE 7. Observed data and recommended values calculated according to Nothing speciﬁed. Eq. ͑1͒ for 3-hydroxybenzoic acid in water

/ 4 ͑ ͒ 4 ͑ ͒ T K10x1 obs 10 x1 rec Components: Original Measurements: ͑1͒ Benzoic acid, 3-hydroxy- 16E. Savarro, Atti Accad. Sci. 286.5 0.0871 0.0882 ͑m-hydroxybenzoic acid͒; Torino 48, 948 ͑1914͓͒Chem. 288.2 0.0913 0.0927 ͓ ͔ ͑ ͔͒ C7H6O3; 99-06-9 Abs. 8, 340 1914 . ͑ ͒ ͓ ͔ 292.0 0.111 0.1043 2 Water; H2O; 7732-18-5 297.5 0.137 0.1256 303.2 0.091 0.1551 Variables: Prepared by: / 304.1 0.180 0.1606 t °C=15 and 50 A. Goto and H. Miyamoto

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Solubility of 3-hydroxybenzoic acid in water Components: Original Measurements: 39 Temperature Solubilitya,b ͑1͒ Benzoic acid, 3-hydroxy- H. Nogami, T. Nagai, and K. ͑m-hydroxybenzoic acid͒; Ito, Chem. Pharm. Bull. 14,351 / −1 ͓ ͔ ͑ ͒ 100w1 m1 mol kg C7H6O3; 99-06-9 1966 . / ͑ ͒ ͑ ͒ ͑ ͒ ͓ ͔ t °C Original data compiler compiler 2 Water; H2O; 7732-18-5

15 7.00 0.700 0.0510 Variables: Prepared by: 50 40.0 4.00 0.3017 t/ °C=30 A. Goto, R. Goto, and H. Miyamoto aIn the original paper, the solubility was given as grams per 1000 g of water. b The value w1 was calculated by the compiler. Solubility of 3-hydroxybenzoic acid in water Auxiliary Information Temperature Solubility Method/Apparatus/Procedure: 2 / −1 The experimental detail is given in the compilation of Ref. 16 for the 10 m1 mol kg salicylic acid–water system in Sec. 2.1.1.1. 3-Hydroxybenzoic acid was t/ °C %a ͑compiler͒ determined gravimetrically after evaporation of the solvent. 30 0.768 5.06 Source and Purity of Materials: a 3-Hydroxybenzoic acid was recrystallized. The compiler assumed that “%” should be read “mass %.”

Estimated Errors: Auxiliary Information Solubility: precision Ϯ1.5%. Method/Apparatus/Procedure: Temperature: nothing speciﬁed. The rotating disk method, as described by H. Nogami, T. Nagai, and A. Suzuki, Chem. Pharm. Bull. 14, 329 ͑1966͒, was employed. Every experiment was carried out under the following conditions: the solution of Components: Original Measurements: 100 ml at 30 °C; the disk of 3 cm diameter compressed under 41 ͑1͒ Benzoic acid, 3-hydroxy- S.V. Sidgwick and E.K. 3 tons cm−2; the rotating velocity of disk at 100 r.p.m. The concentration ͑ ͒ ͓ ͔ m-hydroxybenzoic acid ;C7H6O3; 99-06-9 Embank, J. Chem. Soc. of 3-hydroxybenzoic acid was determined according to UV absorption ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 1921, 979. method. The optical density of 3-hydroxybenzoic acid was determined at 231 and 290 nm. Variables: Prepared by: t/ °C=69–201.3 A. Goto and H. Miyamoto Source and Purity of Materials: 3-Hydroxybenzoic acid was of the purest reagent grade.

Solubility of 3-hydroxybenzoic acid in water Estimated Errors: Nothing speciﬁed. Temperature Solubility

/ −1 m1 mol kg 100x1 / ͑ ͒ ͑ ͒ t °C 100w1 compiler compiler

69 6.11 0.471 0.841 79.6 9.85 0.791 1.40 2.1.1.3. 4-Hydroxybenzoic acid 84.6 14.70 1.248 2.199 93.3 25.22 2.442 4.214 98.3 33.85 3.705 6.257 Components: Evaluators: 109.8 49.85 7.197 11.48 ͑1͒ Benzoic acid, 4-hydroxy- Ayako Goto, University of 134.0 70.80 17.55 24.02 ͑p-hydroxybenzoic acid͒; Shizuoka, Shizuoka, Japan; ͓ ͔ 201.3 100.0 — 100.0 C7H6O3; 99-96-7 Rensuke Goto, University of ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Shizuoka, Shizuoka, Japan; Hiroshi Miyamoto, Niigata Auxiliary Information University, Niigata, Japan; Hiroshi Fukuda, Kitasato Method/Apparatus/Procedure: University, Tokyo, Japan The experimental detail is given in the compilation of Ref. 41 for the salicylic acid–water system in Sec. 2.1.1.1.

Source and Purity of Materials: The preparation and puriﬁcation methods were described by J. Walker and J.K. Wood, J. Chem. Soc. 117,40͑1920͒. Melting point of 3-hydroxybenzoic acid was 201.5 °C.

Estimated Errors: Nothing speciﬁed.

J. Phys. Chem. Ref. Data, Vol. 40, No. 1, 2011

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Critical Evaluation TABLE 8. Summary of experimental solubility data of 4-hydroxybenzoic acid in water

/ 2 / −3 2 / −1 4 T K10c1 mol dm 10 m1 mol kg 10 x1 Analytical method Reference

278.15 0.0159 0.0286a Titration ͑NaOH͒ 13 284.15 0.0228 0.0411a Titration ͑NaOH͒ 13 a ͑ ͑ ͒ ͒ 285.9 0.0222 0.0400 Titration Ba OH 2 15 288.2 0.032 0.0576a Gravimetry 16 289.15 0.0299 0.0538a Titration ͑NaOH͒ 13 293.15 0.0374 0.0673a Titration ͑NaOH͒ 13 293.2 0.0347 Spectrophotometry 42 a ͑ ͑ ͒ ͒ 294.1 0.0356 0.0641 Titration Ba OH 2 15 298.15 0.0489 0.0880a Titration ͑NaOH͒ 13 298.2 0.0335 Spectrophotometry 43 and 44 298.2 0.0427 Titration ͑alkali solution͒ 33 298.35 0.0451 Titration ͑NaOH͒ 35 303.15 0.0634 0.114a Titration ͑NaOH͒ 13 303.2 0.0529 0.0952a Spectrophotometry 39 307.15 0.0812 0.146a Titration ͑NaOH͒ 13 a ͑ ͑ ͒ ͒ 307.6 0.0715 0.129 Titration Ba OH 2 15 312.15 0.103 0.185a Titration ͑NaOH͒ 13 a ͑ ͑ ͒ ͒ 312.6 0.0877 0.158 Titration Ba OH 2 15 316.15 0.139 0.249a Titration ͑NaOH͒ 13 a ͑ ͑ ͒ ͒ 319.2 0.131 0.236 Titration Ba OH 2 15 321.15 0.180 0.324a Titration ͑NaOH͒ 13 323.2 0.216 0.38a Gravimetry 16 324.1 0.177 0.317a Synthetic method 41 326.15 0.244 0.43a Titration ͑NaOH͒ 13 a ͑ ͑ ͒ ͒ 327.8 0.198 0.356 Titration Ba OH 2 15 329.2 0.239 0.429a Synthetic method 41 330.15 0.333 0.596a Titration ͑NaOH͒ 13 333.4 0.317 0.569a Synthetic method 41 335.15 0.429 0.766a Titration ͑NaOH͒ 13 336.2 0.361 0.646a Synthetic method 41 338.3 0.399 0.713a Synthetic method 41 340.15 0.567 1.02a Titration ͑NaOH͒ 13 341.4 0.468 0.83a Synthetic method 41 345.15 0.727 1.29a Titration ͑NaOH͒ 13 348.9 0.740 1.32a Synthetic method 41 353.3 0.977 1.72a Synthetic method 41 362.8 1.77 3.09a Synthetic method 41 370.2 3.03 5.17a Synthetic method 41 382.7 6.32 10.2a Synthetic method 41 387.2 7.83 12.4a Synthetic method 41 410.7 18.0 24.5a Synthetic method 41 440.2 41.7 42.9a Synthetic method 41 486.2 100.0a Synthetic method 41 a / −1 The mole-fraction solubilities were calculated based upon m1 mol kg or w1 The critical evaluation was carried out as described in shown in Fig. 3, where the data above 373.2 K were ex- Sec. 2.1.1.1. for salicylic acid in water: cluded to compare with the result of salicylic acid, but they The number of publications: 10 deviated from Eq. ͑2͒ in the range of higher and lower tem- The range of temperature: 278.15–486.2 K perature. Multiple regression analysis according to Eq. ͑1͒ The unit: mass percent, mole fraction, and molar concen- gave the following results: tration Multiple correlation coefﬁcient: 0.997 Analytical methods: synthetic method, and titration Sample size: 34 Data in Table 8 for the solubility of 4-hydroxybenzoic p-value ͑F test͒: 0.000 acid in water expressed by mole fraction were ﬁtted to Eqs. Constants: A=8381Ϯ2073, B=44.07Ϯ6.52, C= ͑1͒ and ͑2͒ given in Sec. 1.3. The data points very closely −290.9Ϯ44.1 agree with Eq. ͑1͒ in the range from 286.5 to 371.5 K, as White circles in Fig. 3 represent the observed data and

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Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy- 15J. Walker and J.K. Wood, J. ͑p-hydroxybenzoic acid͒; Chem. Soc. Trans. 73,618 ͓ ͔ ͑ ͒ C7H6O3; 99-96-7 1898 . ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=0.0–54.6 A. Goto and H. Miyamoto

Solubility of 4-hydroxybenzoic acid in water

a b FIG. 3. Fitting curve of Eq. ͑1͒ and the observed data for 4-hydroxybenzoic Temperature Observed solubility Calculated solubility acid in water. / −1 / −1 Original 100w1 m1 mol kg 100S m1 mol kg t/ ͑ ͒ ͑ ͒ ͑ ͒ ͑ ͒ the black line corresponds to calculated values according to °C data compiler compiler compiler compiler ͑ ͒ ͑ / ͒ Eq. 1 ln x1 =8381 T+44.07 ln T−290.9 . The observed 0.0 — — — 0.160 0.0116 data fit closely with the calculated line in the range of 12.7 0.307 0.306 0.0222 0.310 0.0224 278.15–370.2 K, with the multiple correlation coefficient of 20.9 0.492 0.490 0.0356 0.476 0.0345 0.997, as shown in Fig. 3. Therefore, the calculated value at 34.4 0.987 0.977 0.0715 0.963 0.0697 each measured temperature is reasonably considered as a rec- 39.4 1.211 1.197 0.08767 1.244 0.09006 ommended value in the whole range of temperature. 46.0 1.815 1.782 0.1314 1.766 0.1279 54.6 2.740 2.667 0.1984 2.768 0.2004 Table 9 shows typical observed data in the range of 278.15–370.2 K selected from among the sources in Table 8, aIn the original paper, the solubility was given as grams per hundred grams and the recommended values calculated from Eq. ͑1͒ at each of solvent. The value w1 was calculated by the compiler. b temperature. The solubility was calculated from the equation log10 S=0.0227t −0.079 72, where S ͑symbol given in the original paper͒ is the solubility by TABLE 9. Observed data and recommended values calculated according to weight and t is the temperature in degrees Centigrade. Eq. ͑1͒ for 4-hydroxybenzoic acid in water Auxiliary Information / 4 ͑ ͒ 4 ͑ ͒ T K10x1 obs 10 x1 rec Method/Apparatus/Procedure: 278.15 0.0286 0.0298 The experimental detail is given in the compilation of Ref. 15 for the 284.15 0.0411 0.0404 salicylic acid–water system in Sec. 2.1.1.1. 285.9 0.04 0.0442 Source and Purity of Materials: 288.2 0.0576 0.0498 No information was given. 293.15 0.0673 0.0645 324.1 0.317 0.350 Estimated Errors: 327.8 0.356 0.432 Nothing specified. 329.2 0.429 0.467 294.1 0.0641 0.0678 298.15 0.088 0.0841 Components: Original Measurements: 303.2 0.0952 0.110 ͑1͒ Benzoic acid, 4-hydroxy- 16E. Savarro, Atti Accad. Sci. 307.15 0.146 0.137 ͑p-hydroxybenzoic acid͒; Torino 48, 948 ͑1914͓͒Chem. 312.15 0.185 0.180 ͓ ͔ ͑ ͔͒ C7H6O3; 99-96-7 Abs. 8, 340 1914 . ͑ ͒ ͓ ͔ 312.6 0.158 0.185 2 Water; H2O; 7732-18-5 316.15 0.249 0.225 319.2 0.236 0.266 Variables: Prepared by: / 321.15 0.324 0.297 t °C=15 and 50 A. Goto and H. Miyamoto 324.1 0.317 0.350 327.8 0.356 0.432 Solubility of 4-hydroxybenzoic acid in water 329.2 0.429 0.467 330.15 0.596 0.493 Temperature Solubilitya 333.4 0.569 0.593 w m / −1 336.2 0.646 0.695 100 1 1 mol kg t/ °C Original data ͑compiler͒ ͑compiler͒ 338.3 0.713 0.783 341.4 0.836 0.935 15 4.4 0.44 0.032 345.15 1.29 1.16 50 29.8 2.98 0.216 348.9 1.32 1.44 a 353.3 1.72 1.85 In the original paper, the solubility was given as grams per 1000 g of water.

362.8 3.09 3.20 The value w1 was calculated by the compiler. 370.2 5.17 4.91

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Auxiliary Information Components: Original Measurements: Method/Apparatus/Procedure: ͑1͒ Benzoic acid, 4-hydroxy- 39H. Nogami, T. Nagai, and K. The experimental detail is given in the compilation of Ref. 16 for the ͑p-hydroxybenzoic acid͒; Ito, Chem. Pharm. Bull. 14,351 ͓ ͔ ͑ ͒ salicylic acid–water system in Sec. 2.1.1.1. The 4-hydroxybenzoic acid C7H6O3; 99-96-7 1966 . ͑ ͒ ͓ ͔ was determined gravimetrically after evaporation of the solvent. 2 Water; H2O; 7732-18-5

Source and Purity of Materials: Variables: Prepared by: 4-Hydroxybenzoic acid was recrystallized. t/ °C=30 A. Goto, R. Goto, and H. Miyamoto Estimated Errors: Solubility: precision Ϯ1.5%. Solubility of 4-hydroxybenzoic acid in water Temperature: nothing speciﬁed.

Temperature Solubility

2 / −1 Components: Original Measurements: 10 m1 mol kg a ͑1͒ Benzoic acid, 4-hydroxy- 41S.V. Sidgwick and E.K. t/ °C % ͑compiler͒ ͑p-hydroxybenzoic acid͒; Embank, J. Chem. Soc. 1921, ͓ ͔ 30 0.735 5.29 C7H6O3; 99-96-7 979. ͑2͒ Water; H O; ͓7732-18-5͔ 2 aThe compiler assumed that “%” should be read “mass %.” Variables: Prepared by: Auxiliary Information t/ °C=50.9–213.0 A. Goto and H. Miyamoto Methods/Apparatus/Procedure: Solubility of 4-hydroxybenzoic acid in water The experimental detail is given in the compilation of Ref. 39 for the salicylic acid–water system in Sec. 2.1.1.1. The optical density of Temperature Solubility 4-hydroxybenzoic acid was determined at 250 nm. Source and Purity of Materials: 100x1 / ͑ ͒ 4-Hydroxybenzoic acid was of the purest reagent grade. t °C 100w1 compiler

50.9 2.38 0.317 Estimated Errors: 56.0 3.20 0.429 Nothing speciﬁed. 60.2 4.20 0.569 63.0 4.75 0.646 65.1 5.22 0.713 Components: Original Measurements: 68.2 6.07 0.836 ͑1͒ Benzoic acid, 4-hydroxy- 42T.C. Corby and P.H. Elworthy, 75.7 9.28 1.32 ͑p-hydroxybenzoic acid͒; J. Pharm. Pharmacol. 23, Suppl, ͓ ͔ ͑ ͒ 80.1 11.85 1.723 C7H6O3; 99-96-7 39S 1971 . ͑ ͒ ͓ ͔ 89.6 19.66 3.093 2 Water; H2O; 7732-18-5 97.0 29.47 5.168 Variables: Prepared by: 109.5 46.60 10.22 t/ °C=20 A. Goto and H. Miyamoto 114.0 51.95 12.36 137.5 71.30 24.47 167.0 85.20 42.88 Solubility of 4-hydroxybenzoic acid in water 213.0 100.0 100.0 Temperature Solubility

/ 2 / −3 Auxiliary Information t °C 10 c1 mol dm

Methods/Apparatus/Procedure: 20 0.0347 The experimental detail is given in the compilation of Ref. 41 for the salicylic acid–water system in Sec. 2.1.1.1. Auxiliary Information

Source and Purity of Materials: Methods/Apparatus/Procedure: The preparation and puriﬁcation methods were described by J. Walker and The solubility was determined as described by P.H. Elworthy and F.J. ͑ ͒ J.K. Wood, J. Chem. Soc. 117,40 1920 . Melting point of Lipscomb, J. Pharm. Pharmacol. 20,790͑1968͒. The solution was assayed 4-hydroxybenzoic acid was 213.0 °C. by ultraviolet spectroscopy.

Estimated Errors: Source and Purity of Materials: Nothing speciﬁed. 4-Hydrdoxybenzoic acid ͑BDH Ltd., Lab. reagent͒ was recrystallized from distilled water and dried overnight at 40 °C in a vacuum over phosphorous pentaoxide; m.p. 214 °C.

Estimated Errors: Not stated.

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Auxiliary Information Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy- 43P.L. Wu and A. Martin, J. Methods/Apparatus/Procedure: ͑ ͒ ͑ ͒ p-hydroxybenzoic acid ; Pharm. Sci. 72, 587 1983 The mole fraction solubility x1 of 4-hydroxybenzoic acid was determined ͓ ͔ 82 C7H6O3; 99-96-7 A. Martin, P.L. Wu, Z. Liron, as described by A. Beerbower, A. Martin, and P.L. Wu, J. Pharm. Sci. 73, ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 and S. Cohen, J. Pharm. Sci. 74, 179 ͑1984͒. A suitable amount of water was introduced into screw-capped 638 ͑1985͒. vials containing an excess amount of the solute. After being sealed with several turns of plastic tape, the vials were submerged in water at 25 °C Variables: Prepared by: and shaken. After equilibrium had been attained, each vial was removed, t/ °C=25 A. Goto and H. Miyamoto wiped dry, and analyzed. The solutions were transferred to a syringe and ﬁltered using a ﬁlter of pore size Ͻ1 ␮m. After suitable dilution, the solutions were assayed using a spectrophotometer. The solubility was Solubility of 4-hydroxybenzoic acid in water determined at least six times.

Temperature Solubility Source and Purity of Materials: 4-Hydroxybenzoic acid was obtained from Matheson, Coleman and Bell t/ °C x c /mol dm−3 1 1 and the acid was recrystallized from aqueous alcohol and dried at 105 °C. 25 0.000 60 0.0335 Melting point measured by a hot-stage method is 486.85 K. Estimated Errors: Auxiliary Information Nothing speciﬁed.

Methods/Apparatus/Procedure: A suitable amount of water was introduced into screw-capped vials Components: Original Measurements: containing an excess amount of solute. After being sealed with several ͑1͒ Benzoic acid, 4-hydroxy 13A. Apelblat and E. Manzurola, turns of electrical tape, the vials were submerged in water at 25 °C and ͑p-hydroxybenzoic acid͒; J. Chem. Thermodyn. 29, 1527 shaken at 100 cpm for 24 h in a constant-temperature bath. After C H O ; ͓99-96-7͔ ͑1997͒. equilibrium had been attained, the saturated solutions were transferred to a 7 6 3 ͑2͒ Water; H O ͓7732-18-5͔ syringe and ﬁltered by a ﬁlter of pore size Ͻ1 ␮m. The solutions were 2 assayed using a spectrophotometer. The solubility of the solute was Variables: Prepared by: determined at least six times. T/K=278.15–345.15 A. Goto, R. Goto, and H. Source and Purity of Materials: Miyamoto The 4-hydroxybenzoic acid ͑Matheson Coleman Bell, Norwood, OH͒ was recrystallized from aqueous ethanol and dried at 105 °C overnight. Solubility of 4-hydroxybenzoic acid in water A pure grade of dioxane ͑Mallinckrodt Chem. Works, St. Louis, MO͒ was used as received. Temperature Observed solubility Calculated solubilitya

Estimated Errors: / / −1 T K m1 mol kg Solubility: The experimental variation in solubility was Ͻ3% in replicate samples. 278.15 0.0159 0.0161 Temperature: precision Ϯ0.1 °C. 284.15 0.0228 0.0223 289.15 0.0299 0.0294 293.15 0.0374 0.0368 Components: Original Measurements: 298.15 0.0489 0.0488 ͑1͒ Benzoic acid, 4-hydroxy- 44A Martin, P.L. Wu, and A. 303.15 0.0634 0.0649 ͑p-hydroxybenzoic acid͒; Beerbower, J. Pharm. Sci. 73, 307.15 0.0812 0.0816 ͓ ͔ ͑ ͒ C7H6O3; 99-96-7 188 1984 . 312.15 0.1027 0.1090 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 316.15 0.1385 0.1375 321.15 0.1804 0.1842 Variables: Prepared by: 326.15 0.2438 0.2471 t/ °C=25 A. Goto, R. Goto, and H. 330.15 0.3330 0.3127 Miyamoto 335.15 0.4286 0.4202 340.15 0.5666 0.5652 Solubility of 4-hydroxybenzoic acid in water 345.15 0.7269 0.7606

a ͓ /͑ −1͔͒ Temperature Solubility The author reported the ﬁtting equation ln m1 mol kg =−275.673 / 4 ͑ / ͒−1 ͑ / ͒ t °C 10 x1 +7891.58 T K +43.384 ln T K . The solubility was calculated from the ﬁtting equation by the compiler. 25 6.0

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Auxiliary Information TABLE 10. Summary of experimental solubility data of methylparaben in water—Continued Methods/Apparatus/Procedure: / 2 / −3 2 / −1 4 The solubility measurements were performed as described by A. Apelblat T K10c1 mol dm 10 m1 mol kg 10 x1 Analytical method Reference and E. Manzurola, J. Chem. Thermodyn. 19, 317 ͑1987͒. Suspended in excess, solid was dissolved in distilled water by stirring for 10 h in 298.2 2.72a Spectrophotometry 46 double-wall tubes thermostated by circulating water. The stirring was 298.2 2.86 Spectrophotometry 48 followed by gravitational settling overnight. Weighed samples of saturated 298.2 2.60a Spectrophotometry 57 solutions were titrated with solutions of NaOH, standardized with 300.2 1.45 Spectrophotometry 5 potassium hydrogen phthalate. Phenolphthalein was used as an indicator. 298.2 1.65 Spectrophotometry 58 a Source and Purity of Materials: 300.2 3.04 Spectrophotometry 59 4-Hydroxybenzoic acid was obtained from Aldrich. The purity of the 303.15 3.12 Spectrophotometry 45 reagent was more than 0.99 mass % fraction and was used without further 303.2 1.56 Not reported 60 purification. 303.2 1.66 Spectrophotometry 61 303.2 3.24 Spectrophotometry 56 Estimated Errors: 303.2 3.28a Spectrophotometry 46 Nothing specified. 303.2 3.30a Spectrophotometry 57 308.15 3.74 Spectrophotometry 45 308.2 3.97a Spectrophotometry 46 2.2. Paraben–water systems 308.2 4.01a Spectrophotometry 56 2.2.1. Critical evaluation of the solubility of 308.2 4.11a Spectrophotometry 57 parabens 310.15 4.05 Spectrophotometry 45 313.15 4.53 Spectrophotometry 45 2.2.1.1. Methylparaben 313.2 4.80a Spectrophotometry 46 313.2 4.92 Spectrophotometry 56 Components: Evaluators: 313.2 6.83 Spectrophotometry 48 a ͑1͒ Benzoic acid, 4-hydroxy-, Ayako Goto, University of 313.2 4.61 Spectrophotometry 57 methyl ester ͑methyl Shizuoka, Shizuoka, Japan; 318.15 5.63 Spectrophotometry 45 p-hydroxybenzoate; Rensuke Goto, University of 318.2 5.83a Spectrophotometry 46 ͒ methylparaben ;C8H8O3 Shizuoka, Shizuoka, Japan; 323.15 6.83 Spectrophotometry 45 ͓99-76-3͔ Hiroshi Fukuda, Kitasato 323.2 7.08b Spectrophotometry 46 ͑ ͒ ͓ ͔ 2 Water; H2O 7732-18-5 University, Tokyo, Japan 323.2 7.55 Spectrophotometry 48 328.2 8.60a Spectrophotometry 46 Critical Evaluation 331.5 9.83a Spectrophotometry 46 TABLE 10. Summary of experimental solubility data of methylparaben in 331.65 9.37 Spectrophotometry 45 water a / −1 The mole-fraction solubilities were calculated based on m1 mol kg or w1. bThe molar fraction was calculated from w , but the value was not used for T/K102c /mol dm−3 102m /mol kg−1 104x Analytical method Reference 1 1 1 1 the evaluation. 273.15 1.09 Spectrophotometry 45 Solubilities of methylparaben in water were reported in 273.2 1.14a Spectrophotometry 46 19 publications. The measurements were carried out from 278.15 1.27 Spectrophotometry 45 273.15 to 331.65 K. The solubilities are shown in Table 10, a 278.2 1.34 Spectrophotometry 46 in which mass percent and mole fraction as well as molar 283.15 1.54 Spectrophotometry 45 concentration are expressed as units. The measurements were 283.2 1.59a Spectrophotometry 46 carried out mainly by spectroscopy, as shown in Table 10. 288.15 1.79 Spectrophotometry 45 288.2 0.831 Spectrophotometry 47 Data of the solubility of methylparaben in water ex- 288.2 1.85 Spectrophotometry 48 pressed by mole fraction can be treated as a function of ab- 288.2 1.90a Spectrophotometry 46 solute temperature. They were fitted to Eqs. ͑1͒ and ͑2͒ given 293.15 2.15 Spectrophotometry 45 in Sec. 1.3. The data points very closely agree with Eq. ͑1͒ in 293.2 2.27a Spectrophotometry 46 the whole range of temperatures, as shown in Fig. 4, but they 288.2 0.997 Spectrophotometry 47 deviate from Eq. ͑2͒ in the range of higher and lower tem- 288.2 1.26 Spectrophotometry 49 perature. The equation parameters were derived by multiple 298.15 2.67 Spectrophotometry 45 regression analysis using SPSS based on Eq. ͑1͒, with the 298.2 1.14 Spectrophotometry 47 298.2 1.45 Spectrophotometry 50 following results: 298.2 1.49 Gravimetry 51 Multiple correlation coefficient: 0.994 298.2 1.60 Spectrophotometry 52 Sample size: 41 298.2 1.610 HPLC analysis 53 p-value ͑F test͒: 0.000 298.2 1.90 3.419b Spectrophotometry 54 Constants: A=6007Ϯ2123, B=31.37Ϯ7.06, C= 298.2 2.46 Spectrophotometry 55 −207.1Ϯ47.4 298.2 2.61 Spectrophotometry 56 White circles in Fig. 4 represent the observed data and 298.2 2.70 Spectrophotometry 44 the black line corresponds to calculated values according to

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Solubility of methylparaben in water

Temperature Solubility

/ 3 / −3 t °C 10 c1 mol dm

27 1.45

Auxiliary Information

Methods/Apparatus/Procedure: The excess paraben was put in glass stoppered flasks containing 10 ml FIG. 4. Fitting curve of Eq. ͑1͒ and the observed data for methylparaben in water. The flasks were then shaken at 27Ϯ0.1 °C in an incubator ͑Taiyo water. incubator, M-I type͒ to attain equilibrium. After a given volume of the supernatant was diluted adequately with water, the concentration of the ͑ ͒ ͑ / ͒ paraben in the solution was determined by measuring the absorbance at Eq. 1 ln x1 =6007 T+31.37 ln T−207.1 . The observed 256 nm ͑HITACHI 101 Spectrophotometer͒. data fit closely with the calculated line in the range of Source and Purity of Materials: 273.2–331.5 K, with the multiple correlation coefficient of Methylparaben is of reagent grade. The water was used after treatment of 0.994, as shown in Fig. 4. Therefore, the calculated value at distilled water by ion exchange and distillation from an all-Pyrex glass each measured temperature is reasonably considered as a rec- distillation apparatus. ommended value in the whole range of temperature. Estimated Errors: Table 11 shows typical observed data in the range of Solubility: nothing specified. Temperature: precision Ϯ0.1 °C. 273.2–331.5 K selected from among the sources in Table 10 and the recommended values calculated from Eq. ͑1͒ at each temperature. Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 57K.S. Alexander, B. Laprade, ͑ TABLE 11. Observed data and recommended values calculated according to methyl ester methyl J.W. Mauger, and A.N. Paruta, J. Eq. ͑1͒ for methylparaben in water p-hydroxybenzoate; Pharm. Sci. 67, 624 ͑1978͒. ͒ methylparaben ;C8H8O3; ͓ ͔ T/K104x ͑obs͒ 104x ͑rec͒ 99-76-3 1 1 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 273.2 1.14 1.09 278.2 1.34 1.30 Variables: Prepared by: / 283.2 1.59 1.55 t °C=25–40 A. Goto, R. Goto, and H. Miyamoto 288.2 1.85 1.86 293.2 2.27 2.24 298.2 2.70 2.70 Solubility of methylparaben in water 300.2 3.04 2.91 303.2 3.24 3.26 Temperature Solubility 308.2 3.97 3.95 t/ °C 105x 310.15 4.05 4.26 1 313.2 4.8 4.79 25 26.0 318.2 5.83 5.82 30 33.0 323.2 7.08 7.09 35 41.1 328.2 8.6 8.65 40 46.1 331.5 9.83 9.86

Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 5A. Goto, F. Endo, and K. Ito, methyl ester ͑methyl Chem. Pharm. Bull. 25, 1165 p-hydroxybenzoate; ͑1977͒. ͒ methylparaben ;C8H8O3; ͓99-76-3͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=27 A. Goto

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Auxiliary Information Source and Purity of Materials: No information of source and purification of the materials were reported. Methods/Apparatus/Procedure: The m.p. of methylparaben was 131 °C Solubility was determined by a method previously described ͓P.A. Schwartz and A.N. Paruta, J. Pharm. Sci. 65,252͑1976͔͒. The paraben, in Estimated Errors: an amount in excess of its solubility, was placed in screw-capped glass Nothing specified. vials with water. After equilibrium solubility was attained by at least 24 h of continuous rotation, each of six sample vials was removed in succession for assay. A filtered aliquot of the saturated solution was Components: Original Measurements: pipetted into tared containers, weighed, and appropriately diluted for ͑ ͒ 56 spectrophotometer assay with 95% ethanol to give a final concentration of 1 Benzoic acid, 4-hydroxy-, R.E. Lindstrom and C.H. Lee, ͑ solute in the range of 1–5 ␮g/ml. All pipets were prewarmed to prevent methyl ester; methyl J. Pharm. Pharmacol. 32,245 ͑ ͒ thermal precipitation, and each had a pledget of fiberglass wrapped around p-hydroxybenzoate; 1980 . ͒ its tip to act as a filter. The spectrophotometer was calibrated for paraben methylparaben ;C8H8O3; ͓ ͔ at its wavelength of maximum absorbance, at concentrations up to 99-76-3 ͑ ͒ ͓ ͔ 15 ␮g/ml in 95% ethanol. A least-squares method was used to determine 2 Water; H2O; 7732-48-5 the statistical significance ͑␣=0.0001͒ of the linear relationship between Variables: Prepared by: absorbance and concentration. The spectrophotometer was Cary model 16, t/ °C=25–40 A. Goto, R. Goto, and H. Cary Instruments, Monrovia, CA. Miyamoto Source and Purity of Materials: Methylparaben: Lot 14, Matheson, Coleman and Bell. Solubility of methylparaben in water The solute was within 1 °C of the literature melting-point value. Temperature Solubility Estimated Errors: Temperature: precision Ϯ0.2 °C. / 4 t °C 10 x1

25 2.61 Components: Original Measurements: 30 3.24 ͑1͒ Benzoic acid, 4-hydroxy-, 50S.H. Yalkowsky and S.C. 35 4.01 methyl ester ͑methyl Valvani, J. Pharm. Sci. 69, 912 40 4.92 p-hydroxybenzoate; ͑1980͒. methylparaben͒;CH O ; 8 8 3 Auxiliary Information ͓99-76-3͔ ͑2͒ Water; H O; ͓7732-18-5͔ 2 Methods/Apparatus/Procedure: Variables: Prepared by: The solubility of the methylparaben in water was determined at various t/ °C=25 A. Goto, R. Goto, and H. temperatures in the range 25–41.36 °C according to the procedure Miyamoto described in Ref. 80. The solubility was analyzed using a Beckmann DU spectrophotometer.

Solubility of methylparaben in water Source and Purity of Materials: Not stated. Temperature Solubilitya Estimated Errors: 2 / −3 10 c1 mol dm Nothing speciﬁed. / ͑ ͒ t °C −log10 sobs compiler

25 1.84 1.45

aThe solubility s was given as moles per liter.

Auxiliary Information

Methods/Apparatus/Procedure: Solubility of methylparaben was determined by UV spectrophotometer ͓G.L. Flynn and S.H. Yalkowsky, J. Pharm. Sci. 61, 838 ͑1972͔͒.A moderate excess of the paraben was placed in an appropriately sized stoppered flasks, water was added to the capacity of the flask, and the flask was placed in a 37 °C shaker bath and agitated gently for 6–8 days. An appropriately sized sample for the paraben was removed via a warmed, glass-wool-tipped pipet and appropriately diluted for analysis. A minimum dilution of 100% ͑50–100 ml͒ was used to prevent crystallization at ambient temperature. The absorption maximum at 285 nm was measured and compared with a simultaneously prepared standard. The standard solutions were prepared by dissolving accurately weighed samples ͑10 or 1.0 mg͒ of each compound in 10 ml of 95% ethanol. In each case, there were diluted 100-fold with de-ionized water and assayed using 1 or 10 cm cells, respectively.

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Source and Purity of Materials: Components: Original Measurements: Methylparaben of purest grade was obtained from commercial sources 60 ͑1͒ Benzoic acid, 4-hydroxy-, C. McDonald and C. ͑Aldrich, Eastman and Fluka͒ and was used as received. methyl ester ͑methyl Richardson, J. Pharm. Pharmacol. p-hydroxybenzoate; 33,38͑1981͒. Estimated Errors: ͒ methylparaben ;C8H8O3; Nothing speciﬁed. ͓99-76-3͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Components: Original Measurements: ͑ ͒ 46 t/ °C=30 A. Goto, R. Goto, and H. 1 Benzoic acid, 4-hydroxy-, D.J.W. Grant, M. Mehdizadeh, ͑ Miyamoto methyl ester methyl A.H.-L. Chow, and J.E. p-hydroxybenzoate, Fairbrother, Int. J. Pharm. 18,25 ͒ ͑ ͒ methylparaben ;C8H8O3; 1984 . Solubility of methylparaben in water ͓99-76-3͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Temperature Solubility Variables: Prepared by: 2 / −3 10 c1 mol dm T/K=273.2–331.5 A. Goto, R. Goto, and H. t/ °C ͑compiler͒ Miyamoto

30 1.56 Solubility of methylparaben in water

Auxiliary Information Temperature Solubilitya

Methods/Apparatus/Procedure: / 4 ͑ ͒ T K10x1 compiler Not stated. 273.2 1.14 Source and Purity of Materials: 278.2 1.34 Not stated. 283.2 1.59 288.2 1.90 Estimated Errors: 293.2 2.27 Not stated. 298.2 2.72 303.2 3.28 308.2 3.97 Components: Original Measurements: 313.2 4.80 ͑1͒ Benzoic acid, 4-hydroxy-, 61S.H. Yalkowsky, S.C. Valvani, 318.2 5.83 methyl ester ͑methyl and T.J. Roseman, J. Pharm. Sci. 323.2 7.08 p-hydroxybenzoate; 72,866͑1983͒. ͒ 328.2 8.60 methylparaben ;C8H8O3; ͓99-76-3͔ 331.2 9.83 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 aThe solubility was calculated from the regression equation at round tem- Variables: Prepared by: peratures by the compiler. t/ °C=30 A. Goto, R. Goto, and H. Miyamoto Auxiliary Information

Methods/Apparatus/Procedure: Solubility of methylparaben in water A small amount of the solid solute, in excess of the solubility limit, was placed with 10 cm3 of water in a borosilicate glass test tube, which was Temperature Solubilitya equilibrated in a thermostatic water bath. The content of each tube was agitated by means of glass rod stirrers. To obtain temperatures below 2 / −3 10 c1 mol cm room temperature, the water bath was kept in a cold room at 4 °C. / ͑ ͒ t °C log10 s1 compiler Saturation was achieved within 72 h at 15–25 °C and within 120 h at 0–10 °C. The solubility above 25 °C was determined by agitating in 30 −1.78 1.66 conical ﬂasks placed in a thermostatic shaking incubator for 24 h. For

a analysis the sample solutions were withdrawn through a warm Pasteur In the original paper, s is the solubility in moles per liter. pipette containing a glass wool plug. At different time intervals, triplicate samples were removed. Solubility was determined by UV spectroscopy. Auxiliary Information Source and Purity of Materials: Methods/Apparatus/Procedure: The methylparaben was supplied by B.D.H. Chemicals, Toronto and was An excess amount of solute was allowed to equilibrate with water in a recrystallized from toluene to constant melting point. The water was sealed vial for 24 h at 300 °C. After equilibration, the samples were double-distilled in an all-glass apparatus. filtered through either a 0.22 ␮m porous or a 1.2 ␮m silver membrane filter which was preequilibrated at 30 °C. Analysis of the filtrate was Estimated Errors: performed using UV spectrophotometry. Solubility: nothing specified. Temperature: precision Ϯ0.05 °C.

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Results were analyzed from the observed data with the Components: Original Measurements: sat ͑ / ͒͑ / ͒ ͑ / ͒ equation ln x1 =− a R 1 T + b R ln T+C, where R is the ͑1͒ Benzoic acid, 4-hydroxy-, 59J.T. Rubino and E.K. Obeng, J. gas constant. methyl ester ͑methyl Pharm. Sci. 80, 479 ͑1991͒. p-hydroxybenzoate; ͑ ͒ ͒ Temperature Regression coefﬁcients with statistics methylparaben ;C8H8O3; ͓99-76-3͔ / ͑ ͒ ͓ ͔ −a R 2 Water; H2O; 7732-18-5 t/ °C na K−1 sb tc b/Rsb tc C Variables: Prepared by: 0.0–58.3 13 6520 752 9.0 32.86 2.42 13.6 −217.3 t/ °C=27 A. Goto, R. Goto, and H. Correlation coefﬁcient Miyamoto

xsat T xsat T ln 1 vs ln ln 1 vs ln Multiple Solubility of methylparaben in water r r r2

−0.996 0.998 1.000 Temperature Solubility x a Number of mean data points. 1 t/ °C ͑compiler͒ bStandard deviation of the regression coefﬁcient. c Student’s t-value; all signiﬁcant at the 5% level. 27 0.000 304

Components: Original Measurements: Auxiliary Information ͑1͒ Benzoic acid, 4-hydroxy-, 44A. Martin, P.L. Wu, and A. methyl ester ͑methyl Beerbower, J. Pharm. Sci. 73, Methods/Apparatus/Procedure: p-hydroxybenzoate; 188 ͑1984͒. The solubility of methylparaben was determined by placing an excess ͒ methylparaben C8H8O3; amount of the paraben in 4 ml screw-capped vials with water and rotating ͓99-76-3͔ in a temperature-controlled water bath at 27 °C for 72 h. The saturated ͑ ͒ ͓ ͔ ␮ 2 Water; H2O; 7732-18-5 solutions were filtered through a 0.5 m solvent-resistant filter. A weighed aliquot of the filtrate was diluted with HPLC grade ethanol and assayed Variables: Prepared by: spectrophotometrically. t/ °C=25 A. Goto, R. Goto, and H. Miyamoto Source and Purity of Materials: Methylparaben of high purity was obtained from Sigma Chemical Company and used as received from the supplier. The m.p. was 131 °C Solubility of methylparaben in water and the value agreed with that described in Ref. 46.

Temperature Solubility Estimated Errors: Solubility: the variation of triplicate experiments was Ͻ5%. / 4 t °C 10 x1 Temperature: Ϯ0.2 °C. 25 2.7

Components: Original Measurements: Auxiliary Information 47 ͑1͒ Benzoic acid, 4-hydroxy-, A.E. Beezer, S. Forster, W.-B. methyl ester ͑methyl Park, and G.J. Rimmer, Methods/Apparatus/Procedure: p-hydroxybenzoate; Thermochim. Acta 178,59 The mole fraction solubilities x of methylparaben were determined as 1 methylparaben͒;CH O ; ͑1991͒. described by A. Beerbower, A. Martin, and P.L. Wu, J. Pharm. Sci. 73, 8 8 3 ͓99-76-3͔ 179 ͑1984͒. A suitable amount of water was introduced into screw-capped ͑2͒ Water; H O; ͓7732-18-5͔ vials containing an excess amount of the solute. After being sealed with 2 several turns of plastic tape, the vials were submerged in water at 25 °C Variables: Prepared by: and shaken. After equilibrium had been attained, each vial was removed, T/K=288.2, 293.2, and 298.2 A. Goto, R. Goto, and H. wiped dry, and analyzed. The solutions were transferred to a syringe and Miyamoto ﬁltered using a ﬁlter of pore size Ͻ1 ␮m. After suitable dilution, the solutions were assayed using a spectrophotometer. The solubility was determined at least six times for each solvent. Solubility of methylparaben in water

Source and Purity of Materials: Temperature Solubility Methylparaben ͑Tenneco Chemical Inc.͒ was used. The m.p. measured by / / −3 a hot-stage method is 399.65 K. T K c1 mol dm

Estimated Errors: 288.2 8.31ϫ10−3 Solubility: errors were below 3%. 293.2 9.97ϫ10−3 Temperature: precision Ϯ0.2 °C. 298.2 1.14ϫ10−2

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Auxiliary Information Source and Purity of Materials: No information was given. Methods/Apparatus/Procedure: The measurement of solubility was similar to that described by A.E. Estimated Errors: Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35, 350 Nothing speciﬁed. ͑1983͒. Absorbance measurements were made at 258 nm.

Source and Purity of Materials: Components: Original Measurements: The methylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great ͑1͒ Benzoic acid, 4-hydroxy-, 53F. Giordano, R. Bettini, C, Britain͒ and was used as received. The purity was speciﬁed as Ͼ99.5%. methyl ester ͑methyl Donini, A. Gazzanig, M.R. Caira, Ethanol was of Anala R grade. p-hydroxybenzoate; G.G.Z. Zhang, and D.J.W. Grant, ͒ ͑ ͒ Estimated Errors: methylparaben ;C8H8O3; J. Pharm. Sci. 88, 1210 1999 . ͓ ͔ Nothing speciﬁed. 99-76-3 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Components: Original Measurements: t/ °C=25 A. Goto, R. Goto, and H. ͑1͒ Benzoic acid, 4-hydroxy-, 45R. J. Prankerd, Int. J. Pharm. Miyamoto methyl ester ͑methyl 84,233͑1992͒. p-hydroxybenzoate, ͒ Solubility of methylparaben in water methylparaben ;C8H8O3; ͓99-76-3͔ ͑ ͒ ͓ ͔ Temperature Solubility 2 Water; H2O; 7732-18-5 102c /mol dm−3 Variables: Prepared by: 1 t/ °C ͑compiler͒ T/K=273.15–331.15 A. Goto, R. Goto, and H. Miyamoto 25 1.610

Solubility of methylparaben in water Auxiliary Information

Temperature Solubilitya Methods/Apparatus/Procedure: The solubility was determined by equilibrating the liquid phase with a / 4 T K10x1 known weight of the paraben in powdered form at 25.0Ϯ0.5 °C with agitation. A 5 day period had previously been shown to afford 273.15 1.0877 equilibrium. The three independent sets of experiments were performed on 278.15 1.2667 the paraben. After equilibration at 25.0Ϯ0.5 °C, the suspension was 283.15 1.5433 filtered through a 0.22 ␮m Millipore filter. The filtrate, after appropriate 288.15 1.7856 dilution with the mobile phase, was assayed. The sample of solution 293.15 2.1537 appropriately diluted with the mobile phase ͑methanol/0.04M ammonium 298.15 2.6670 acetate, 55:45, v:v͒ was analyzed with an HPLC system ͑LC-19AS, ͒ ͑ ͒ ␭ 303.15 3.1238 Shimadzu, Japan ; detector UV-vis, SPD-10 A, Shimadzu at =256 nm: column ͑C-18 Bondapak, Waters, Milford, MA͒ 10 ␮m, 3.9ϫ300 nm; 308.15 3.7432 flow rate of 0.8 ml min−1. Peak integration was performed with a C-R6A 310.15 4.0503 chromatopac ͑Shimadzu, Japan͒. Linearity of response in the 313.15 4.5298 0–20 mgml−1 concentration range was assessed from plots of peak area 318.15 5.6349 against concentration. 323.15 6.8287 331.15 9.3746 Source and Purity of Materials: Methylparaben was obtained from Sigma Company ͑St. Louis, MO͒ and aUnpublished data provided by D. J. W. Grant and M. Mehdizadeh were was used as received. Organic solvents were of chromatographic grade used to fit the theoretical equation. Analysis procedure was given in the purity. Double-distilled water was used for solubility experiments. original paper. Also, see Ref. 46. Estimated Errors: Ϯ Auxiliary Information Temperature: 0.5 °C.

Methods/Apparatus/Procedure: The solubilities of the paraben were determined by agitating the materials in conical ﬂasks placed in a thermostatic shaking incubator. Saturation 2.2.1.2. Ethylparaben was then achieved within 24 h. For analysis each sample of solution of the paraben was quickly withdrawn through a warm Pasteur pipette containing a glass plug to act as a ﬁlter. At different time intervals, Components: Evaluators: triplicate samples were removed, weighed, and analyzed and the mean ͑1͒ Benzoic acid, 4-hydroxy-, Ayako Goto, University of composition was determined at saturation. The solubility was determined ethyl ester ͑ethyl Shizuoka, Shizuoka, Japan; by a spectrophotometer at 257 nm.46 p-hydroxybenzoate; Rensuke Goto, University of ͒ ethylparaben ;C9H10O3 Shizuoka, Shizuoka, Japan; ͓120-47-8͔ Hiroshi Fukuda, Kitasato ͑ ͒ ͓ ͔ 2 Water; H2O 7732-18-5 University, Tokyo, Japan

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Critical Evaluation TABLE 12. Summary of experimental solubility data of ethylparaben in water

/ 2 / −3 4 T K10c1 mol dm 10 x1 Analytical method Reference

273.15 0.424 Spectrophotometry 45 273.2 0.401a Spectrophotometry 46 278.15 0.480 Spectrophotometry 45 278.2 0.458a Spectrophotometry 46 283.15 0.557 Spectrophotometry 45 283.2 0.531a Spectrophotometry 46 288.15 0.650 Spectrophotometry 45 ͑ ͒ 288.2 0.623a Spectrophotometry 46 FIG. 5. Fitting curve of Eq. 1 and the observed data for ethylparaben in water. 288.2 0.275 Spectrophotometry 47 293.15 0.789 Spectrophotometry 45 a 293.2 0.739 Spectrophotometry 46 Sample size: 32 293.2 0.337 Spectrophotometry 47 ͑ ͒ 298.15 0.992 Spectrophotometry 45 p-value F test : 0.000 298.2 0.638 Spectrophotometry 51 Constants: A=12550Ϯ1411, B=53.35Ϯ4.69, C= a 298.2 0.887 Spectrophotometry 46 −355.4Ϯ31.5 298.2 0.603 Spectrophotometry 50 White circles in Fig. 5 represent the observed data and 298.2 0.409 Spectrophotometry 47 298.2 0.96 Spectrophotometry 57 the black line corresponds to calculated values according to ͑ ͒ ͑ / ͒ 300.2 0.62 Spectrophotometry 58 Eq. 1 ln x1 =12550 T+53.35 ln T−355.4 . The observed 300.2 0.54 Spectrophotometry 5 data fit closely with the calculated line in the range of 300.2 1.02a Spectrophotometry 59 303.15 1.03 Spectrophotometry 45 273.2–331.2 K, with the multiple correlation coefficient of 303.2 0.631 Spectrophotometry 61 0.998, as shown in Fig. 5. Therefore, the calculated value at 303.2 1.07a Spectrophotometry 46 each measured temperature is reasonably considered as a rec- 303.2 1.22 Spectrophotometry 57 ommended value in the whole range of temperature. 308.15 1.35 Spectrophotometry 45 308.2 1.31a Spectrophotometry 46 Table 13 shows typical observed data in the range of 308.2 1.49 Spectrophotometry 57 273.2–331.2 K selected from among the sources in Table 12 310.15 1.56 Spectrophotometry 45 and the recommended values calculated from Eq. ͑1͒ at each 313.15 1.71 Spectrophotometry 45 temperature. 313.2 1.62a Spectrophotometry 46 313.2 1.72 Spectrophotometry 57 318.15 2.11 Spectrophotometry 45 TABLE 13. Observed data and recommended values calculated according to a Eq. ͑1͒ for ethylparaben in water 318.2 2.02 Spectrophotometry 46 323.15 2.73 Spectrophotometry 45 T/K104x ͑obs͒ 104x ͑rec͒ 323.2 2.53a Spectrophotometry 46 1 1 328.15 3.32 Spectrophotometry 45 273.2 0.401 0.407 328.2 3.19 Spectrophotometry 46 278.2 0.458 0.470 331.2 3.76 Spectrophotometry 46 283.2 0.531 0.548 331.65 3.93 Spectrophotometry 45 288.2 0.623 0.646 a / −1 293.2 0.739 0.769 The mole-fraction solubilities were calculated based on m1 mol kg or w1. The critical evaluation was carried out as described in 298.2 0.887 0.925 300.2 1.02 0.998 Sec. 2.2.1.1 for methylparaben in water: 308.2 1.31 1.37 The number of publications: 10 310.15 1.56 1.49 The range of temperature: 273.15–331.65 K 313.2 1.72 1.69 The unit: mole fraction and molar concentration 318.2 2.02 2.09 Analytical methods: spectrophotometry 323.2 2.53 2.61 Data in Table 12 for the solubility of ethylparaben in 328.2 3.19 3.28 water expressed by mole fraction were fitted to Eqs. ͑1͒ and 331.2 3.76 3.77 ͑2͒ given in Sec. 1.3. The data points very closely agree with Eq. ͑1͒ in the whole range of temperatures, as shown in Fig. 5, but they deviate from Eq. ͑2͒ in the range of higher and lower temperatures. Multiple regression analysis according to Eq. ͑1͒ produced the following: Multiple correlation coefficient: 0.998

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Source and Purity of Materials: Components: Original Measurements: Ethylparaben: Lot EX665. Matheson, Coleman, and Bell. ͑ ͒ 5 1 Benzoic acid, 4-hydroxy-, A. Goto, F. Endo, and K. Ito, The solute was within 1 °C of the literature melting point value. ethyl ester ͑ethyl Chem. Pharm. Bull. 25, 1165 p-hydroxybenzoate; ͑1977͒. Estimated Errors: ͒ ethylparaben ;C9H10O3 Temperature: precision Ϯ0.2 °C. ͓120-47-8͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Components: Original Measurements: 50 t/ °C=27 A. Goto ͑1͒ Benzoic acid, 4-hydroxy-, S.H. Yalkowsky and S.C. ethyl ester ͑ethyl Valvani, J. Pharm. Sci. 69,912 p-hydroxybenzoate; ͑1980͒. Solubility of ethylparaben in water ͒ ethylparaben ;C9H10O3; ͓120-47-8͔ ͑ ͒ ͓ ͔ Temperature Solubility 2 Water; H2O; 7732-18-5 / 3 / −3 t °C 10 c1 mol dm Variables: Prepared by: t/ °C=25 A. Goto, R. Goto, and H. 27 5.4 Miyamoto

Auxiliary Information Solubility of ethylparaben in water Methods/Apparatus/Procedure: Temperature Solubilitya All procedures were identical to those given in the compilation of Ref. 5 for the methylparaben–water system in Sec. 2.2.1.1. 3 / −3 10 c1 mol dm t/ °C log s ͑compiler͒ Source and Purity of Materials: 10 obs Ethylparaben was of reagent grade. Water was purified by distillation from 25 Ϫ2.22 6.03 deionized water. aThe solubility s was given as moles per liter. Estimated Errors: Solubility: nothing specified. Auxiliary Information Temperature: precision Ϯ0.1 °C. Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 50 for the Components: Original Measurements: methylparaben–water system in Sec. 2.2.1.1 ͑ ͒ 57 1 Benzoic acid, 4-hydroxy-, K.S. Alexander, B. Laprade, Source and Purity of Materials: ethyl ester ͑ethyl J.W. Mauger, and A.N. Paruta, J. No information on source and purification of the materials were reported. p-hydroxybenzoate; Pharm. Sci. 67, 624 ͑1978͒. ͒ The m.p. of ethylparaben was 116 °C. ethylparaben ;C9H10O3; ͓ ͔ 120-47-8 Estimated Errors: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Nothing specified. Variables: Prepared by: t/ °C=25–40 A. Goto, R. Goto, and H. Miyamoto Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 61S.H. Yalkowsky, S.C. Valvani, ethyl ester ͑ethyl and T.J. Roseman, J. Pharm. Sci. Solubility of ethylparaben in water 4-hydroxybenzoate; 72, 866 ͑1983͒. ͒ ethylparaben ;C9H10O3; Temperature Solubility ͓120-47-8͔ ͑ ͒ ͓ ͔ / 5 2 Water; H2O; 7732-18-5 t °C 10 x1 Variables: Prepared by: 25 9.6 t/ °C=30 A. Goto, R. Goto, and H. 30 12.2 Miyamoto 35 14.9 40 17.2 Solubility of ethylparaben in water

Auxiliary Information a Temperature Solubility

Methods/Apparatus/Procedure: 3 / −3 10 c1 mol cm The experimental detail is given in the compilation of Ref. 57 for the / ͑ ͒ t °C log10 s1 compiler methylparaben–water system in Sec. 2.2.1.1. 30 −2.20 6.31

aIn the original paper, s is the solubility in moles per liter.

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Auxiliary Information Temperature Regression coefﬁcients ͑with statistics͒

Methods/Apparatus/Procedure: −a/R a b c b c The experimental detail is given in the compilation of Ref. 61 for the t/ °C n K−1 s t b/Rs t C methylparaben–water system in Sec. 2.2.1.1. 0.00–58.5 14 13 977 1832 7.6 58.04 6.09 9.5 −386.9 Source and Purity of Materials: Correlation coefficient Purest grade ethylparaben was obtained from commercial sources sat / sat ͑Aldrich, Eastman, and Fluka͒ and was used as received. ln x1 vs 1 T ln x1 vs ln T Multiple r r r2 Estimated Errors: −0.990 0.993 0.998 Nothing specified. aNumber of mean data points. bStandard deviation of the regression coefficient. Components: Original Measurements: cStudent’s t-value; all significant at the 5% level. ͑1͒ Benzoic acid, 4-hydroxy-, 46D.J.W. Grant, M. Mehdizadeh, ethyl ester ͑ethyl A.H.-L. Chow, and J.E. p-hydroxybenzoate; Fairbrother, Int. J. Pharm. 18,25 Components: Original Measurements: ͒ ͑ ͒ 59 ethylparaben ;C9H10O3; 1984 . ͑1͒ Benzoic acid, 4-hydroxy-, J.T. Rubino and E.K. Obeng, J. ͓120-47-8͔ ethyl ester ͑ethyl Pharm. Sci. 80, 479 ͑1991͒. ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 p-hydroxybenzoate acid; ͒ ethylparaben ;C9H10O3; Variables: Prepared by: ͓120-47-8͔ T/K=273.2–331.2 A. Goto and H. Miyamoto ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Solubility of ethylparaben in water t/ °C=27 A. Goto, R. Goto, and H. Miyamoto Temperature Solubilitya

/ 5 a T K10x1 Solubility of ethylparaben in water 273.2 4.01 Temperature Solubility 278.2 4.58

283.2 5.31 x1 288.2 6.23 t/ °C ͑compiler͒ 293.2 7.39 298.2 8.87 27 0.000 102 303.2 10.7 308.2 13.1 Auxiliary Information 313.2 16.2 318.2 20.2 Methods/Apparatus/Procedure: 323.2 25.3 The experimental detail is given in the compilation of Ref. 59 for the 328.2 31.9 methylparaben–water system in Sec. 2.2.1.1. 331.2 37.6 Source and Purity of Materials: aThe solubility was calculated from the regression equation at round tem- Ethylparaben of high purity was obtained from Sigma Chemical Company and used as received. The m.p. was 116 °C and the value agreed with that peratures by the compiler. reported in Ref. 46. Auxiliary Information Estimated Errors: Ͻ Methods/Apparatus/Procedure: Solubility: the variation among triplicate samples was 5%. Ϯ The details of the solubility measurements were identical to those given in Temperature: 0.2 °C. the compilation of Ref. 46 for the methylparaben–water system in Sec. 2.2.1.1. The solubility was determined by UV spectroscopy. Components: Original Measurements: Source and Purity of Materials: ͑1͒ Benzoic acid, 4-hydroxy-, 45R. J. Prankerd, Int. J. Pharm. Ethylparaben was supplied by B.D.H. Chemicals, Toronto, and was ethyl ester ͑ethyl 84, 233 ͑1992͒. recrystallized from toluene to constant melting point. The water was p-hydroxybenzoate; double-distilled in an all-glass apparatus. ͒ ethylparaben ;C9H10O3; ͓ ͔ Estimated Errors: 120-47-8 ͑2͒ Water; H O; ͓7732-18-5͔ Solubility: nothing speciﬁed. 2 Temperature: precision Ϯ0.05 °C. Variables: Prepared by: T/K=273.15–331.15 A. Goto and H. Miyamoto Results were analyzed from the observed data with the sat ͑ / ͒͑ / ͒ ͑ / ͒ equation ln x1 =− a R 1 T + b R ln T+C.

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Solubility of ethylparaben in water TABLE 14. Summary of experimental solubility data of propylparaben in water—Continued Temperature Solubilitya / 2 / −3 4 T K10c1 mol dm 10 x1 Analytical method Reference / 5 T K10x1 293.2 0.29a Spectrophotometry 46 273.15 4.238 293.2 0.241 Spectrophotometry 47 278.15 4.800 298.15 0.318 Spectrophotometry 45 283.15 5.566 298.2 0.286 Gravimetry 51 288.15 6.499 298.2 0.257 Spectrophotometry 50 293.15 7.891 298.2 0.361a Spectrophotometry 46 298.15 9.918 298.2 0.332 Spectrophotometry 48 303.15 10.323 298.2 0.257 Spectrophotometry 47 308.15 13.554 298.2 0.37 Spectrophotometry 57 310.15 15.606 300.2 0.22 Spectrophotometry 58 313.15 17.140 300.2 0.436a Spectrophotometry 59 318.15 21.125 303.15 0.407 Spectrophotometry 45 323.15 27.312 303.2 0.21 Not stated 60 328.15 33.191 303.2 0.447 Spectrophotometry 61 331.15 39.329 303.2 0.455a Spectrophotometry 46 aUnpublished data provided by D.J.W. Grant and M. Mehdizadeh were used 303.2 0.44 Spectrophotometry 57 to ﬁt the theoretical equation. Analysis procedure was given in the original 308.15 0.552 Spectrophotometry 45 paper. Also, see Ref. 46. 308.2 0.581a Spectrophotometry 46 308.2 0.55 Spectrophotometry 57 Auxiliary Information 310.15 0.628 Spectrophotometry 45 Methods/Apparatus/Procedure: 313.15 0.852 Spectrophotometry 45 The experimental detail is given in the compilation of Ref. 45 for the 313.2 0.707 Spectrophotometry 48 a methylparaben–water system in Sec. 2.2.1.1. 313.2 0.747 Spectrophotometry 46 313.2 0.73 Spectrophotometry 57 Source and Purity of Materials: 318.15 0.950 Spectrophotometry 45 No information was given. 318.2 0.971 Spectrophotometry 46 323.15 1.29 Spectrophotometry 45 Estimated Errors: 323.2 1.27a Spectrophotometry 46 Nothing speciﬁed. 323.2 1.17 Spectrophotometry 48 328.2 1.68a Spectrophotometry 46

a / −1 2.2.1.3. Propylparaben The mole-fraction solubilities were calculated based upon m1 mol kg or w1. The critical evaluation was carried out as described in Components Evaluators: Sec. 2.2.1.1 for methylparaben in water: ͑1͒ Benzoic acid, 4-hydroxy-, Ayako Goto, University of propyl ester ͑propyl Shizuoka, Shizuoka, Japan; The number of publications: 14 p-hydroxybenzoate; Rensuke Goto, University of The range of temperature: 273.15–328.2 K ͒ propylparaben ;C10H12O3; Shizuoka, Shizuoka, Japan; The unit: mass percent, mole fraction, and molar concen- ͓94-13-3͔ Hiroshi Fukuda, Kitasato tration ͑ ͒ ͓ ͔ 2 Water; H2O 7732-18-5 University, Tokyo, Japan Analytical methods: spectrophotometry and gravimetry Data in Table 14 for the solubility of propylparaben in Critical Evaluation water expressed by mole fraction were fitted to Eqs. ͑1͒ and TABLE 14. Summary of experimental solubility data of propylparaben in ͑2͒ given in Sec. 1.3. The data points very closely agree with water Eq. ͑1͒ in the whole range of temperatures, as shown in Fig. / 2 / −3 4 ͑ ͒ T K10c1 mol dm 10 x1 Analytical method Reference 6, but they deviate from Eq. 2 in the range of higher and lower temperatures. Multiple regression analysis according 273.15 0.132 Spectrophotometry 45 to Eq. ͑1͒ gave the following results: 273.2 0.137a Spectrophotometry 46 Multiple correlation coefficient: 0.997 278.15 0.159 Spectrophotometry 45 278.2 0.161a Spectrophotometry 46 Sample size: 33 283.15 0.193 Spectrophotometry 45 p-value ͑F test͒: 0.000 283.2 0.194a Spectrophotometry 46 Constants: A=17 660Ϯ2103, B=72.80Ϯ7.04, C= 288.15 0.225 Spectrophotometry 45 −484.3Ϯ47.2 288.2 0.235a Spectrophotometry 46 White circles in Fig. 6 represent the observed data and 288.2 0.211 Spectrophotometry 48 the black line corresponds to calculated values according to 288.2 0.205 Spectrophotometry 47 ͑ ͒ ͑ / ͒ Eq. 1 ln x1 =17 660 T+72.80 ln T−484.3 . The observed 293.15 0.272 Spectrophotometry 45 data fit closely with the calculated line in the range of

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Solubility of propylparaben in water

Temperature Solubility

/ 5 t °C 10 x1

25 3.7 30 4.4 35 5.5 40 7.3

Auxiliary Information

Methods/Apparatus/Procedure: FIG. 6. Fitting curve of Eq. ͑1͒ and the observed data for propylparaben in The experimental detail is given in the compilation of Ref. 57 for the water. methylparaben–water system in Sec. 2.2.1.1.

Source and Purity of Materials: 273.2–328.2 K, with the multiple correlation coefﬁcient of Propylparaben: Lot PX 1910, Matheson, Coleman, and Bell. The solute was within 1 °C of the literature melting point value. 0.997, as shown in Fig. 6. Therefore, the calculated value at each measured temperature is reasonably considered as a rec- Estimated Errors: Ϯ ommended value in the whole range of temperature. Temperature: precision 0.2 °C. Table 15 shows typical observed data in the range of 273.2–328.2 K selected from among the sources in Table 14, Components: Original Measurements: and the recommended values calculated from Eq. ͑1͒ at each ͑1͒ Benzoic acid, 4-hydroxy-, 50S.H. Yalkowsky and S.C. ͑ temperature. propyl ester propyl Valvani, J. Pharm. Sci. 69,912 p-hydroxybenzoate; ͑1980͒. ͒ propylparaben ;C10H12O3; TABLE 15. Observed data and recommended values calculated according to ͓94-13-3͔ ͑ ͒ ͑ ͒ ͓ ͔ Eq. 1 for propylparaben in water 2 Water; H2O; 7732-18-5

/ 4 ͑ ͒ 4 ͑ ͒ Variables: Prepared by: T K10x1 obs 10 x1 rec t/ °C=25 A. Goto and H. Miyamoto 273.2 0.137 0.135 278.2 0.161 0.158 Solubility of propylparaben in water 283.2 0.194 0.189 288.2 0.235 0.229 Temperature Solubilitya 293.2 0.29 0.281 298.2 0.361 0.351 3 / −3 10 c1 mol dm / ͑ ͒ 303.2 0.44 0.444 t °C log10 sobs compiler 308.2 0.581 0.567 310.15 0.628 0.626 25 −2.59 2.57 313.2 0.73 0.733 a 318.15 0.95 0.955 In the original paper, s is the solubility in moles per liter. 318.2 0.971 0.958 Auxiliary Information 323.2 1.27 1.263 328.2 1.68 1.68 Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 50 for the methylparaben–water system in Sec. 2.2.1.1. Components: Original Measurements: Source and Purity of Materials: ͑1͒ Benzoic acid, 4-hydroxy-, 57K.S. Alexander, B. Laprade, No information on source and puriﬁcation of the materials was reported. propyl ester ͑propyl J.W. Mauger, and A.N. Paruta, J. The m.p. of propylparaben was 96 °C. p-hydroxybenzoate; Pharm. Sci. 67, 624 ͑1978͒. ͒ propylparaben ;C10H12O3; Estimated Errors: ͓ ͔ 94-13-3 Nothing speciﬁed. ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=25–40 A. Goto, R. Goto, and H. Miyamoto

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Components: Original Measurements: Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 60C. McDonald and C. ͑1͒ Benzoic acid, 4-hydroxy-, 46D.J.W. Grant, M. Mehdizadeh, propyl ester ͑propyl Richardson, J. Pharm. Pharmacol. propyl ester ͑propyl A.H.-L. Chow, and J.E. p-hydroxybenzoate; 33,38͑1981͒. p-hydroxybenzoate; Fairbrother, Int. J. Pharm. 18,25 ͒ ͒ ͑ ͒ propylparaben ;C10H12O3; propylparaben ;C10H12O3; 1984 . ͓94-13-3͔ ͓94-13-3͔ ͑ ͒ ͓ ͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 2 Water; H2O; 7732-18-5

Variables: Prepared by: Variables: Prepared by: t/ °C=30 A. Goto, R. Goto, and H. T/K=273.2–328.2 A. Goto and H. Miyamoto Miyamoto

Solubility of propylparaben in water Solubility of propylparaben in water Temperature Solubility Temperature Solubility / 5 a T K10x1 2 / −3 10 c1 mol dm t/ °C ͑compiler͒ 273.2 1.37 278.2 1.61 30 0.21 283.2 1.94 288.2 2.35 Auxiliary Information 293.2 2.90 298.2 3.61 Methods/Apparatus/Procedure: 303.2 4.55 Not stated. 308.2 5.81 313.2 7.47 Source and Purity of Materials: 318.2 9.71 Not stated. 323.2 12.7 Estimated Errors: 328.2 16.8 Not stated. aThe solubility was calculated from the regression equation at round temperatures by the compiler.

Components: Original Measurements: Auxiliary Information ͑1͒ Benzoic acid, 4-hydroxy-, 61S.H. Yalkowsky, S.C. Valvani, propyl ester ͑propyl and T.J. Roseman, J. Pharm. Sci. Methods/Apparatus/Procedure: p-hydroxybenzoate; 72,866͑1983͒. The details of the solubility measurements were identical to those given in ͒ propylparaben ;C10H12O3; the compilation of Ref. 46 for the methylparaben–water system in Sec. ͓94-13-3͔ 2.2.1.1. The solubility was determined by UV spectroscopy. ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Source and Purity of Materials: Variables: Prepared by: The propylparaben was supplied by B.D.H. Chemicals, Toronto, and was t/ °C=30 A. Goto and H. Miyamoto recrystallized from toluene to constant melting point. The water was double-distilled in an all-glass apparatus.

Solubility of propylparaben in water Estimated Errors: Solubility: nothing speciﬁed. Temperature Solubility Temperature: precision Ϯ0.05 °C. 3 / −3 10 c1 mol cm t/ °C log s ͑compiler͒ 10 1 Results were analyzed from the observed data with the 30 −2.35 4.47 sat ͑ / ͒͑ / ͒ ͑ / ͒ equation ln x1 =− a R 1 T + b R ln T+C.

Auxiliary Information

Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 61 for the methylparaben–water system in Sec. 2.2.1.1.

Source and Purity of Materials: Propylparaben of purest grade was obtained from commercial sources ͑Aldrich, Eastman, and Fluka͒ and was used as received.

Estimated Errors: Nothing speciﬁed.

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Temperature Regression coefﬁcients ͑with statistics͒ 2.2.1.4. Butylparaben

−a/R t/ °C na K−1 sb tc b/Rsb tc t Components: Evaluators: ͑1͒ Benzoic acid, 4-hydroxy-, Ayako Goto, University of 0.00–55.0 13 16 194 4501 3.6 67.81 15.05 4.5 −450.9 butyl ester ͑butyl Shizuoka, Shizuoka, Japan; p-hydroxybenzoate; Rensuke Goto, University of Correlation coefﬁcient ͒ butylparaben ;C11H14O3; Shizuoka, Shizuoka, Japan; ln xsat vs 1/T ln xsat vs ln T Multiple ͓94-26-8͔ Hiroshi Fukuda, Kitasato 1 1 ͑ ͒ ͓ ͔ r r r2 2 Water; H2O; 7732-18-5 University, Tokyo, Japan

−0.988 0.991 0.992 Critical Evaluation aNumber of mean data points. TABLE 16. Summary of experimental solubility data of butylparaben in bStandard deviation of the regression coefﬁcient. water cStudent’s t-value; all signiﬁcant at the 5% level. / 2 / −3 4 T K10c1 mol dm 10 x1 Analytical method Reference

Components: Original Measurements: 273.15 0.0986 Spectrophotometry 45 a ͑1͒ Benzoic acid, 4-hydroxy-, 45R. J. Prankerd, Int. J. Pharm. 273.2 0.103 Spectrophotometry 46 propyl ester ͑propyl 84,233͑1992͒. 278.15 0.110 Spectrophotometry 45 p-hydroxybenzoate; 278.2 0.121a Spectrophotometry 46 ͒ propylparaben ;C10H12O3; 283.15 0.138 Spectrophotometry 45 ͓94-13-3͔ 283.2 0.143a Spectrophotometry 46 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 288.15 0.163 Spectrophotometry 45 a Variables: Prepared by: 288.2 0.169 Spectrophotometry 46 288.2 0.0704 Spectrophotometry 47 T/K=273.15–323.15 A. Goto and H. Miyamoto 293.15 0.196 Spectrophotometry 45 293.2 0.107 Spectrophotometry 42 Solubility of propylparaben in water 293.2 0.202a Spectrophotometry 46 293.2 0.0835 Spectrophotometry 47 a Temperature Solubility 298.15 0.229 Spectrophotometry 45 / 5 298.2 0.0747 Gravimetry 51 T K10x1 298.2 0.129 Spectrophotometry 50 273.15 1.3175 298.2 0.242a Spectrophotometry 46 278.15 1.5880 298.2 0.105 Spectrophotometry 47 283.15 1.9307 298.2 0.23 Spectrophotometry 57 288.15 2.2486 300.2 0.12 Spectrophotometry 58 293.15 2.7195 300.2 0.11 Spectrophotometry 5 298.15 3.1817 303.15 0.255 Spectrophotometry 45 303.15 4.0655 303.2 0.117 Spectrophotometry 61 308.15 5.5164 303.2 0.292a Spectrophotometry 46 310.15 6.2766 303.2 0.289a Spectrophotometry 61 313.15 8.5245 303.2 0.32 Spectrophotometry 57 318.15 9.5012 308.15 0.350 Spectrophotometry 45 323.15 12.9076 308.2 0.353a Spectrophotometry 46 308.2 0.4 Spectrophotometry 57 a Unpublished data provided by D.J.W. Grant and M. Mehdizadeh were used 313.2 0.47 Spectrophotometry 57 to ﬁt the theoretical equation. Analysis procedure was given in the original a / −1 paper. Also, see Ref. 46. The mole-fraction solubilities were calculated based on m1 mol kg or w1. The critical evaluation was carried out as described in Auxiliary Information Sec. 2.2.1.1: Methods/Apparatus/Procedure: The number of publications: 10 The experimental detail is given in the compilation of Ref. 45 for the The range of temperature: 273.15–313.2 K methylparaben–water system in Sec. 2.2.1.1. The unit: mole fraction, and molar concentration

Source and Purity of Materials: Analytical methods: gravimetry, and spectrophotometry No information was given. Data in Table 16 for the solubility of butylparaben in water expressed by mole fraction were ﬁtted to Eqs. ͑1͒ and Estimated Errors: ͑2͒ given in Sec. 1.3. The data points closely agree with Eq. Nothing speciﬁed. ͑1͒ in the whole range of temperatures, as shown in Fig. 7, but they deviate from Eq. ͑2͒ in the range of higher and lower temperature. The results of multiple regression analysis according to Eq. ͑1͒ were as follows:

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Solubility of butylparaben in water

Temperature Solubility

/ 3 / −3 t °C 10 c1 mol dm

27 1.1

Auxiliary Information

Methods/Apparatus/Procedure: The procedure was identical to that given in the compilation of Ref. 5 for the methylparaben–water system in Sec. 2.2.1.1. The measurement was FIG. 7. Fitting curve of Eq. ͑1͒ and the observed data for butylparaben in carried out by spectroscopy. water. Source and Purity of Materials: Butylparaben was of reagent grade. Water was purified by distillation from Multiple correlation coefficient: 0.994 de-ionized water. Sample size: 21 Estimated Errors: p-value ͑F test͒: 0.000 Solubility: nothing specified. Constants: A=15130Ϯ4557, B=62.77Ϯ15.63, C= Temperature: precision Ϯ0.1 °C. −419.0Ϯ104.4 White circles in Fig. 7 represent the observed data and Components: Original Measurements: the black line corresponds to calculated values according to ͑1͒ Benzoic acid, 4-hydroxy-, 57K.S. Alexander, B. Laprade, ͑ ͒ ͑ / ͒ Eq. 1 ln x1 =15130 T+62.77 ln T−419.0 . The observed butyl ester ͑butyl J.W. Mauger, and A.N. Paruta, J. data fit closely with the calculated line in the range of p-hydroxybenzoate; Pharm. Sci. 67, 624 ͑1978͒. ͒ 273.2–313.2 K, with the multiple correlation coefficient of butylparaben ;C11H14O3; ͓94-26-8͔ ͑ ͒ ͓ ͔ 0.994, as shown in Fig. 7. Therefore, the calculated value at 2 Water; H2O; 7732-18-5 each measured temperature is reasonably considered as a rec- Variables: Prepared by: ommended value in the whole range of temperature. t/ °C=25–40 A. Goto, R. Goto, and H. Table 17 shows typical observed data in the range of Miyamoto 273.2–313.2 K selected from among the sources in Table 16 ͑ ͒ and the recommended values calculated from Eq. 1 at each Solubility of butylparaben in water temperature. Temperature Solubility TABLE 17. Observed data and recommended values calculated according to t/ °C 105x Eq. ͑1͒ for butylparaben in water 1 25 2.3 T/ 4x ͑ ͒ 4x ͑ ͒ K101 obs 10 1 rec 30 3.2 273.2 0.103 0.101 35 4.0 278.2 0.121 0.117 40 4.7 283.2 0.143 0.137 288.2 0.169 0.163 Auxiliary Information 293.2 0.202 0.196 298.2 0.242 0.238 Methods/Apparatus/Procedure: 303.2 0.292 0.293 The experimental detail is given in the compilation of Ref. 57 for the 308.2 0.353 0.364 methylparaben–water system in Sec. 2.2.1.1. 313.2 0.47 0.456 Source and Purity of Materials: Butylparaben: J.T. Baker Chemical Co. The solute was within 1 °C of the literature melting point value. Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 5A. Goto, F. Endo, and K. Ito, Estimated Errors: butyl ester ͑butyl Chem. Pharm. Bull. 25, 1165 Temperature: precision Ϯ0.2 °C. p-hydroxybenzoate; ͑1977͒. ͒ butylparaben ;C11H14O3; ͓94-26-8͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=27 A. Goto

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Auxiliary Information Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 50S.H. Yalkowsky and S.C. Methods/Apparatus/Procedure: butyl ester ͑butyl Valvani, J. Pharm. Sci. 69, 912 The experimental detail is given in the compilation of Ref. 61 for the p-hydroxybenzoate; ͑1980͒. methylparaben–water system in Sec. 2.2.1.1. ͒ butylparaben C11H14O3; ͓94-26-8͔ Source and Purity of Materials: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Butylparaben of purest grade was obtained from commercial sources ͑Aldrich, Eastman, and Fluka͒ and was used as received. Variables: Prepared by: t/ °C=25 A. Goto and H. Miyamoto Estimated Errors: Nothing speciﬁed.

Solubility of butylparaben in water

Temperature Solubility Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 46D.J.W. Grant, M. Mehdizadeh, 3 / −3 ͑ 10 c1 mol dm butyl ester butyl A.H.-L. Chow, and J.E. / ͑ ͒ t °C log10 sobs compiler p-hydroxybenzoate; Fairbrother, Int. J. Pharm. 18,25 ͒ ͑ ͒ butylparaben ;C11H14O3; 1984 . 25 −2.89 1.29 ͓94-26-8͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Auxiliary Information Variables: Prepared by: T/K=273.2–308.2 A. Goto and H. Miyamoto Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 50 for the methylparaben–water system in Sec. 2.2.1.1. Solubility of butylparaben in water

Source and Purity of Materials: Temperature Solubility No information of source and puriﬁcation of the materials were reported. / 5 a Melting point of butylparaben was 68 °C. T K10x1

Estimated Errors: 273.2 1.03 Nothing speciﬁed. 278.2 1.21 283.2 1.43 288.2 1.69 Components: Original Measurements: 293.2 2.02 ͑1͒ Benzoic acid, 4-hydroxy-, 61S.H. Yalkowsky, S.C. Valvani, 298.2 2.42 butyl ester ͑butyl and T.J. Roseman, J. Pharm. Sci. 303.2 2.92 p-hydroxybenzoate; 72,866͑1983͒. 308.2 3.53 ͒ butylparaben ;C11H14O3; ͓94-26-8͔ a The solubility was calculated from the regression equation at round tem- ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 peratures by the compiler.

Variables: Prepared by: Auxiliary Information t/ °C=30 A. Goto and H. Miyamoto Methods/Apparatus/Procedure: The details of the solubility measurements were identical to those given in Solubility of butylparaben in water the compilation of Ref. 46 for the methylparaben–water system in Sec. 2.2.1.1. The solubility was determined by UV spectroscopy. Temperature Solubilitya Source and Purity of Materials: 103c /mol dm−3 1 The butylparaben was supplied by B.D.H. Chemicals, Toronto, and was t/ °C log s ͑compiler͒ 10 1 recrystallized from toluene to constant melting point. The water was 30 −2.93 1.17 double-distilled in an all-glass apparatus. Estimated Errors: a In the original paper, s is the solubility in moles per liter. Solubility: nothing speciﬁed. Temperature: precision Ϯ0.05 °C.

Results were analyzed from the observed data with the sat ͑ / ͒͑ / ͒ ͑ / ͒ equation ln x1 =− a R 1 T + b R ln T+C.

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Temperature Regression coefﬁcients ͑with statistics͒ 2.3. Solubility of hydroxybenzoic acid salt–water

−a/R systems t/ °C na K−1 sb tc b/Rsb tc t 2.3.1. Singly substituted hydroxybenzoic acid salts 0.00–35.0 8 7813 7399 1.1 37.15 25.52 1.5 −248.5 2.3.1.1. 2-Hydroxybenzoic acid salts Correlation coefficient ln xsat vs 1/T ln xsat vs 1/T Multiple 1 1 Components: Original Measurements: r r r2 ͑1͒ Benzoic acid, 2-hydroxy-, 62N.V. Sidgwick and E.K. −0.993 0.994 0.991 monolithium salt ͑lithium Ewbank, J. Chem. Soc. 1922, ͒ ͓ ͔ salicylate ;C7H5O3Li; 552-38-5 1844. a ͑ ͒ ͓ ͔ Number of mean data points. 2 Water; H2O; 7732-18-5 bStandard deviation of the regression coefficient. Variables: Prepared by: cStudent’s t-value; all significant at the 5% level. T/K=270.94–411.2 H. Miyamoto

Components: Original Measurements: Solubility of lithium salicylate in water ͑1͒ Benzoic acid, 4-hydroxy-, 45R.J. Prankerd, Int. J. Pharm. butyl ester ͑butyl 84,233͑1992͒. Temperature Solubility p-hydroxybenzoate; butylparaben͒;C H O ; / a 11 14 3 t °C 100w1 100x1 Solid phase ͓94-26-8͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 −2.26 10.17 1.396 A −5.56 20.62 3.145 A Variables: Prepared by: −12.82 35.83 6.525 A T/K=273.15–308.15 A. Goto and H. Miyamoto −8.5 45.25 9.365 B −1.0 49.04 10.74 B Solubility of butylparaben in water 9.0 52.45 12.12 C 3.5b 52.96 12.34 B Temperature Solubilitya 10.0 52.96 12.34 C 28.5 56.50 15.41 C T/K105x 1 32.0 57.50 15.98 C 273.15 0.9860 38.5 59.67 17.22 C b 278.15 1.0976 52.0 64.18 20.13 C b 283.15 1.3819 60.0 66.56 21.87 C 288.15 1.6332 73.0 66.56 21.87 D 293.15 1.9596 113.0 71.46 26.04 D 298.15 2.2862 aA=ice; B=lithium salicylate hexahydrate; C=lithium salicylate monohy- 303.15 2.5485 drate; D=lithium salicylate anhydride. 308.15 3.5017 bMetastable point.

a Unpublished data provided by D.J.W. Grant and M. Mehdizadeh were used Auxiliary Information to fit the theoretical equation. Analysis procedure was given in the original paper. Also, see Ref. 46. Methods/Apparatus/Procedure: The content of the salt was determined by evaporating to dryness. At high Auxiliary Information temperatures, the solubility measurements were made synthetically, by enclosing weighed quantities of the salt and water in small tubes and Methods/Apparatus/Procedure: observing the temperatures at which the last crystals disappeared on slow The experimental detail is given in the compilation of Ref. 45 for the warming. The components of the solid phases were determined by direct methylparaben–water system in Sec. 2.2.1.1. analysis and/or the residue method. The amount of water in each phase was estimated by drying at 100 °C. Source and Purity of Materials: No information was given. Source and Purity of Materials: Lithium salicylate was made by precipitating lithium sulfate solution with Estimated Errors: barium salicylate. Nothing specified. Estimated Errors: Nothing specified.

Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy-, 62N.V. Sidgwick and E.K. monosodium salt ͑sodium Ewbank, J. Chem. Soc. 1922, ͒ ͓ ͔ salicylate ;C7H5O3Na; 54-21-7 1844. ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

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Variables: Prepared by: Solubility of potassium salicylate in water t/ °C=−0.77–137.0 H. Miyamoto Temperature Solubility

/ a Solubility of sodium salicylate in water t °C 100w1 100x1 Solid phase

Temperature Solubility 138.2 74.80 23.29 C

/ a a t °C 100w1 100x1 Solid phase A=ice; B=potassium salicylate monohydrate; C=potassium salicylate anhydride. −0.77 4.94 0.581 A −0.77 13.15 1.675 A Auxiliary Information −5.04b 21.18 2.935 A −1.5 20.06 2.746 B Methods/Apparatus/Procedure: 9.0 29.61 4.519 B See the compilation of Ref. 62 for the system lithium salicylate–water. 12.5 35.03 5.718 B Source and Purity of Materials: 15.2 40.48 7.107 B Potassium salicylate was prepared by the same method as sodium 17.5 44.40 8.242 B salicylate. 20.0 50.00 10.11 B 47.5 55.10 12.08 C Estimated Errors: 78.5 59.32 14.09 C Nothing speciﬁed. 114.0 64.16 16.77 C 137.0 67.95 19.27 C

a Components: Original Measurements: A=ice; B=sodium salicylate hexahydrate; C=sodium salicylate anhydride. ͑ ͒ 62 b 1 Benzoic acid, 2-hydroxy-, N.V. Sidgwick and E.K. Metastable point. monorubidium salt ͑rubidium Ewbank, J. Chem. Soc. 1922, salicylate͒;CH O Rb; 1844. Auxiliary Information 7 5 3 ͓45749-39-1͔ ͑ ͒ ͓ ͔ Methods/Apparatus/Procedure: 2 Water; H2O; 7732-18-5 See the compilation of Ref. 62 for the system lithium salicylate–water. Variables: Prepared by: / Source and Purity of Materials: t °C=−1.62–134.0 H. Miyamoto Sodium salicylate was prepared by neutralizing salicylic acid with the corresponding hydroxide or carbonate. Solubility of rubidium salicylate in water Estimated Errors: Temperature Solubility Nothing speciﬁed. / a t °C 100w1 100x1 Solid phase

−1.62 12.34 1.127 A Components: Original Measurements: −3.69 23.48 2.424 A ͑1͒ Benzoic acid, 2-hydroxy-, 62N.V. Sidgwick and E.K. monopotassium salt ͑potassium Ewbank, J. Chem. Soc. 1922, −6.34 33.81 3.968 A ͒ ͓ ͔ −8.82 42.77 5.706 A salicylate ;C7H5O3K; 578-36-9 1844. ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 −13.17 53.40 8.488 A 8.0 64.85 12.99 B Variables: Prepared by: 21.5 68.15 14.77 B / t °C=−1.82–138.2 H. Miyamoto 27.0 69.84 15.79 B 49.0 74.97 19.53 B Solubility of potassium salicylate in water 73.0 77.96 22.26 B 88.0 79.89 24.34 B Temperature Solubility 134.0 86.36 33.88 B

/ a a t °C 100w1 100x1 Solid phase A=ice; B=rubidium salicylate monohydrate.

−1.82 10.49 1.185 A −3.47 18.82 2.316 A Auxiliary Information −6.52 31.15 4.422 A −8.00 35.80 5.394 A Methods/Apparatus/Procedure: 0 44.08 7.464 B See the compilation of Ref. 62 for the system lithium salicylate–water. 9.0 49.19 8.450 B 24.0 53.33 10.46 B Source and Purity of Materials: 28.5 55.82 11.45 B Rubidium salicylate was prepared by neutralizing salicylic acid with the 61.0 61.31 13.95 C corresponding hydroxide or carbonate. Rubidium carbonate was prepared from a specimen of the alum. The salt obtained was tested 103.8 68.97 18.53 C spectroscopically, and found to be free from other alkali metals. 108.5 70.20 19.42 C

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Solubility of silver salicylate in water Estimated Errors: Temperature Solubility Nothing speciﬁed. / 3 / −3 t °C 10 c1 mol dm

Components: Original Measurements: 25 4.42 ͑1͒ Benzoic acid, 2-hydroxy-, 62N.V. Sidgwick and E.K. monocesium salt ͑cesium Ewbank, J. Chem. Soc. 1922, Auxiliary Information ͒ salicylate ;C7H5O3Cs; 1844. ͓15092-48-2͔ Methods/Apparatus/Procedure: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Saturated solution of the silver salt was prepared in conductance cells through which a stream of previously dried nitrogen, saturated with the Variables: Prepared by: vapor of the solvent, was led to provide stirring. When the conductance / t °C=−1.83–107.0 H. Miyamoto had become constant, samples of the saturated aqueous solutions were withdrawn and analyzed for silver by the potentiometric method. The solubilities in ethanol and methanol were determined by the conductance Solubility of cesium salicylate in water method. The conductance cells were of the type used by I.M. Kolthoff and A. Willman, J. Am. Chem. Soc. 56, 1008 ͑1934͒. Their cell constants Temperature Solubility were determined in the usual way. The specific conductance of methanol / a at 25 °C varied from 2.9 to 5.0 and the range in the corresponding values t °C 100w1 100x1 Solid phase for ethanol was from 0.4ϫ10−4 to 1.2ϫ10−4 cm−1 ⍀−1. The conductance −1.83 16.08 1.264 A of the alcohol was subtracted from the observed specific conductance −4.24 30.97 2.907 A where necessary. −8.08 47.71 5.740 A Source and Purity of Materials: −3.5 65.70 11.32 B Ethanol and methanol were refluxed over silver oxide, distilled, and 4.5 68.24 12.53 B dehydrated with magnesium. The water content of methanol ranged from 20.5 74.59 16.37 B 0% to 0.03%, while that of ethanol varied from 0.01% to 0.07%. The 33.0 80.07 21.13 B silver salt of the acid was precipitated from solution of the corresponding 41.5 83.35 25.03 C sodium salt with a slight excess of silver nitrate. The precipitates were 54.0 85.67 28.50 C washed and recrystallized from hot water. The product was washed with 67.5 89.91 37.28 C water, then with ethanol, and air dried. 84.3 92.80 46.00 D Estimated Errors: 107.0 94.33 52.58 D Nothing specified. aA=ice; B=cesium salicylate monohydrate; C=cesium salicylate hemihy- drate; D=cesium salicylate anhydride. bMetastable point. Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy-, 64N.A. Izmailov and V.S. Auxiliary Information silver salt ͑silver salicylate͒; Chernyi, Zh. Fiz. Khim. 34,319 ͓ ͔ ͑ ͓͒ C7H6O3Ag; 528-93-8 1960 Russ. J. Phys. Chem. Methods/Apparatus/Procedure: ͑ ͒ ͓ ͔ ͑ ͒ ͑ ͔͒ 2 Water; H2O; 7732-18-5 Engl. Transl. 34,149 1960 . See the compilation of Ref. 62 for the system lithium salicylate–water. Variables: Prepared by: Source and Purity of Materials: t/ °C=25 H. Miyamoto Cesium salt was made from a specimen of American pollucite. The cesium salt was tested spectroscopically, and found to be free from other alkali metals. Solubility of silver salicylate in water

Estimated Errors: Temperature Solubility Nothing speciﬁed. / 3 / −1 t °C 10 m1 mol kg

25 4.38 Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy-, 63I. M. Kolthoff, J.J. Lingane, silver salt ͑silver salicylate͒; and W.D. Larson, J. Am. Chem. ͓ ͔ ͑ ͒ C7H6O3Ag; 528-93-8 Soc. 60, 2512 1938 . ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=25 H. Miyamoto

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Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 3-hydroxy-, 62N.V. Sidgwick and E.K. The solubility determination of the silver salt used the radioactive isotope monosodium salt ͑sodium Ewbank, J. Chem. Soc. 1922, 110 ͒ Ag. The silver salt with solvent was placed in a tube, sealed, and 3-hydroxybenzoate ;C7H5O3Na; 1844. placed in an air thermostat. Equilibrium was reached in 16–18 h. The ͓7720-19-6͔ ͑ ͒ ͓ ͔ solution removed from the tube was centrifuged. The samples were 2 Water; H2O; 7732-18-5 withdrawn by a micropipette and run on to a disk of ﬁlter paper, dried, and sealed in tracing cloth or Cellophane. The prepared specimens were Variables: Prepared by: found on a cylindrical counter and their radioactivity was measured. The t/ °C=−3.21–147.5 H. Miyamoto methods of preparing saturated solutions, sampling, and the radioactive measurement are described by N.A. Izmailov and V.S. Chernyi, Zh. Fiz. Solubility of sodium 3-hydroxybenzoate in water Khim. 34,127͑1960͒; Russ. J. Phys. Chem. ͑Engl. Transl.͒ 34,59͑1960͒. The concentration of silver salicylate was analyzed for the silver content. Temperature Solubility Source and Purity of Materials: t/ °C 100w 100x Solid phasea The silver salt of salicylic acid was prepared from silver nitrate labeled 1 1 110 with radioactive Ag and the sodium or potassium salts of the acid. −3.21 14.68 1.899 A Estimated Errors: −8.85 30.53 4.71 A Solubility: relative accuracy is 1%–3% at a conﬁdence limit of 0.95. −17.52 45.16 8.48 A Temperature: precision Ϯ0.5 °C. 10.0 58.78 13.82 B 110.0 64.61 17.94 B 147.5 69.75 20.60 B

aA=ice; B=sodium 3-hydroxybenzoate anhydride.

2.3.1.2. 3-Hydroxybenzoic acid salts Auxiliary Information

Methods/Apparatus/Procedure: Components: Original Measurements: The synthetic method was used. The experimental details were given in ͑ ͒ 62 1 Benzoic acid, 3-hydroxy-, N.V. Sidgwick and E.K. the compilation of Ref. 62 for the lithium salicylate–water system in Sec. ͑ monolithium salt lithium Ewbank, J. Chem. Soc. 1922, 2.3.1.1. ͒ 3-hydroxybenzoate ;C7H5O3Li; 1844. ͓͔ Source and Purity of Materials: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Sodium salt of 3-hydroxybenzoic acid was prepared by neutralizing 3-hydroxybenzoic acid with the corresponding hydroxide or carbonate. Variables: Prepared by: t/ °C=−4.41–122.0 H. Miyamoto Estimated Errors: Nothing speciﬁed. Solubility of lithium 3-hydroxybenzoate in water

Temperature Solubility Components: Original Measurements: ͑1͒ Benzoic acid, 3-hydroxy-, 62N.V. Sidgwick and E.K. t/ °C 100w 100x Solid phasea 1 1 monopotassium salt ͑potassium Ewbank, J. Chem. Soc. 1922, ͒ −4.41 16.02 2.33 A 3-hydroxybenzoate ;C7H5O3K; 1844. ͓17361-85-2͔ −10.78 29.58 4.99 A ͑2͒ Water; H O; ͓7732-18-5͔ −17.67 39.97 7.68 A 2 10.0 52.53 13.46 B Variables: Prepared by: 74.5 55.04 14.68 B t/ °C=−2.41–136.8 H. Miyamoto 104.0 58.47 16.52 B 122.0 61.86 18.57 B Solubility of potassium 3-hydroxybenzoate in water aA=ice; B=lithium 3-hydroxybenzoate anhydride. Temperature Solubility Auxiliary Information / a t °C 100w1 100x1 Solid phase Methods/Apparatus/Procedure: The synthetic method was used. The experimental details were given in −2.41 12.39 1.43 A the compilation of Ref. 62 for the lithium salicylate–water system in Sec. −5.06 22.25 2.775 A 2.3.1.1. −8.59 31.34 4.46 A −19.92 49.39 9.07 A Source and Purity of Materials: 10.0 59.04 12.85 B Lithium salt of 3-hydroxybenzoic acid was made by precipitating lithium 33.5 61.94 14.27 B sulfate solution with the barium salt of the corresponding acid. 95.0 69.60 18.98 B Estimated Errors: 136.8 75.02 23.52 B Nothing speciﬁed. aA=ice; B=potassium 3-hydroxybenzoate anhydride.

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Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 3-hydroxy-, 62N.V. Sidgwick and E.K. The synthetic method was used. The experimental details were given in monocesium salt ͑cesium Ewbank, J. Chem. Soc. 1922, ͒ the compilation of Ref. 62 for the lithium salicylate–water system in Sec. 3-hydroxybenzoate ;C7H5O3Cs; 1844. 2.3.1.1. ͓͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Source and Purity of Materials: Potassium salt of 3-hydroxybenzoic acid was prepared by neutralizing Variables: Prepared by: 3-hydroxybenzoic acid with the corresponding hydroxide or carbonate. t/ °C=−1.97–126.5 H. Miyamoto

Estimated Errors: Nothing speciﬁed. Solubility of cesium 3-hydroxybenzoate in water

Temperature Solubility

/ a Components: Original Measurements: t °C 100w1 100x1 Solid phase ͑1͒ Benzoic acid, 3-hydroxy-, 62N.V. Sidgwick and E.K. monorubidium salt ͑rubidium Ewbank, J. Chem. Soc. 1922, −1.97 16.98 1.348 A ͒ 3-hydroxybenzoate ;C7H5O3Rb; 1844. −4.92 32.84 3.160 A ͓͔ −9.65 48.52 5.919 A ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 −18.50 63.15 10.25 A 10.0 77.10 18.34 B Variables: Prepared by: 19.0 78.52 19.61 B t/ °C=−2.23–130.0 H. Miyamoto 29.0 81.70 22.95 B 35.0 84.45 26.60 B Solubility of rubidium 3-hydroxybenzoate in water 40.0 86.35 29.67 B 41.5b 87.88 32.60 C Temperature Solubility 73.0 89.88 37.21 C / a 126.5 93.42 48.64 C t °C 100w1 100x1 Solid phase a −2.23 14.92 1.399 A A=ice; B=cesium 3-hydroxybenzoate monohydrate; C=cesium −6.41 32.13 3.690 A 3-hydroxybenzoate anhydride. b −13.69 48.88 7.184 A+B Metastable point. 14.0 50.61 7.658 B Auxiliary Information 32.5 54.94 8.982 B 45.0 60.02 10.83 B Methods/Apparatus/Procedure: 64.0 65.04 13.10 C The synthetic method was used. The experimental details were given in 88.0 70.45 16.17 C the compilation of Ref. 62 for the lithium salicylate–water system in Sec. 105.0 74.49 19.11 C 2.3.1.1. 130.0 79.91 24.35 C Source and Purity of Materials: aA=ice; B=rubidium 3-hydroxybenzoate monohydrate; C=rubidium Cesium salt of 3-hydroxybenzoic acid was made from a specimen of 3-hydroxybenzoate anhydride. American pollucite. The cesium salt was tested spectroscopically, and found to be free from other alkali metals. Auxiliary Information Estimated Errors: Methods/Apparatus/Procedure: Nothing speciﬁed. The synthetic method was used. The experimental details were given in the compilation of Ref. 62 for the lithium salicylate–water system in Sec. 2.3.1.1.

Source and Purity of Materials: Rubidium salt of 3-hydroxybenzoic acid was prepared by neutralizing the acid with the corresponding hydroxide or carbonate. Rubidium carbonate 2.3.1.3. 4-Hydroxybenzoic acid salts was prepared from a specimen of the alum. The salt obtained was tested spectroscopically and found to be free from other alkali metals. Components: Original Measurements: 62 Estimated Errors: ͑1͒ Benzoic acid, 4-hydroxy-, N.V. Sidgwick and E.K. ͑ Nothing speciﬁed. monolithium salt lithium Ewbank, J. Chem. Soc. 1922, ͒ 4-hydroxybenzoate ;C7H5O3Li; 1844. ͓61937-89-1͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=−0.98–113.0 H. Miyamoto

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Solubility of lithium 4-hydroxybenzoate in water Auxiliary Information

Temperature Solubility Methods/Apparatus/Procedure: The synthetic method was used. The experimental details were given in the compilation of Ref. 62 for the lithium salicylate–water system in Sec. t/ °C 100w 100x a 1 1 Solid phase 2.3.1.1.

−0.98 5.04 0.659 A Source and Purity of Materials: −2.37 9.81 1.341 A Sodium salt of 4-hydroxybenzoic acid was prepared by neutralizing −5.23 17.88 2.650 A 4-hydroxybenzoic acid with the corresponding hydroxide or carbonate. −9.28 25.96 4.199 A −12.62 b 31.54 5.488 A Estimated Errors: 12.5 30.84 5.280 B Nothing speciﬁed. 0 30.92 5.299 B 85.0 31.96 5.557 B 113.0 35.00 6.308 B Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 62N.V. Sidgwick and E.K. aA=ice; B= lithium 4-hydroxybenzoate anhydride. monopotassium salt ͑potassium Ewbank, J. Chem. Soc. 1922, b ͒ Metastable point. 4-hydroxybenzoate ;C7H5O3K; 1844. ͓13639-20-8͔ ͑ ͒ ͓ ͔ Auxiliary Information 2 Water; H2O; 7732-18-5

Methods/Apparatus/Procedure: Variables: Prepared by: The synthetic method was used. The experimental details were given in t/ °C=−1.43–129.5 H. Miyamoto the compilation of Ref. 62 for the lithium salicylate–water system in Sec. 2.3.1.1. Solubility of potassium 4-hydroxybenzoate in water Source and Purity of Materials: Lithium salt of 4-hydroxybenzoic acid was made by precipitating lithium Temperature Solubility sulfate solution with the barium salt of the corresponding acid. / a t °C 100w1 100x1 Solid phase Estimated Errors: −1.43 8.04 0.821 A Nothing speciﬁed. −3.24 15.55 1.848 A 15.8 29.91 4.184 B 25.8 35.50 5.355 B Components: Original Measurements: 43.0 45.71 7.932 B ͑ ͒ 62 1 Benzoic acid, 4-hydroxy-, N.V. Sidgwick and E.K. 64.4 56.70 11.82 B monosodium salt ͑sodium Ewbank, J. Chem. Soc. 1922, 70.5 59.34 12.99 B 4-hydroxybenzoate͒;CH O Na; 1844. 7 5 3 86.8 63.01 14.84 C ͓114-63-6͔ ͑ ͒ ͓ ͔ 129.5 64.95 15.94 C 2 Water; H2O; 7732-18-5 a Variables: Prepared by: A=ice; B=potassium 4-hydroxybenzoate trihydrate; C=potassium 4-hydroxybenzoate anhydride. t/ °C=−0.77–163.0 H. Miyamoto Auxiliary Information Solubility of sodium 4-hydroxybenzoate in water Methods/Apparatus/Procedure: The synthetic method was used. The details were given in the compilation Temperature Solubility of Ref. 62 for the lithium salicylate–water system in Sec. 2.3.1.1. t/ °C 100w 100x Solid phasea 1 1 Source and Purity of Materials: −0.77 5.075 0.597 A Potassium salt of 4-hydroxybenzoic acid was prepared by neutralizing the −2.07 10.43 1.293 A acid with the corresponding hydroxide or carbonate. 7.0 19.65 2.678 B Estimated Errors: 24.0 31.47 4.914 B Nothing speciﬁed. 36.5 41.32 7.342 B 39.0b 45.61 8.623 B 43.0 45.61 8.623 C Components: Original Measurements: 107.5 50.51 10.30 C ͑1͒ Benzoic acid, 4-hydroxy-, 62N.V. Sidgwick and E.K. 163.0 54.93 12.06 C monorubidium salt ͑rubidium Ewbank, J. Chem. Soc. 1922, ͒ a 4-hydroxybenzoate ;C7H5O3Rb; 1844. A=ice; B=sodium 4-hydroxybenzoate pentahydrate; C=sodium ͓͔ 4-hydroxybenzoate anhydride. ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 bMetastable point. Variables: Prepared by: t/ °C=−1.17–127.0 H. Miyamoto

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Solubility of rubidium 4-hydroxybenzoate in water Auxiliary Information

Temperature Solubility Methods/Apparatus/Procedure: The synthetic method was used. The experimental details were given in / a t °C 100w1 100x1 Solid phase the compilation of Ref. 62 for the lithium salicylate–water system in Sec. 2.3.1.1. −1.17 9.92 0.883 A −2.47 17.47 1.685 A Source and Purity of Materials: −4.22 26.22 2.798 A Cesium salt of 4-hydroxybenzoic acid was made from a specimen of 17.5 35.66 4.297 B American pollucite. The cesium salt obtained was tested spectroscopically, 45.0 45.95 6.441 B and found to be free from other alkali metals. 68.0 55.73 9.248 B Estimated Errors: 94.0 64.95 13.04 C Nothing speciﬁed. 120.5 74.00 18.72 C 127.0 75.92 20.33 C

aA=ice; B=rubidium 4-hydroxybenzoate monohydrate; C=rubidium Components: Original Measurements: ͑ ͒ 64 4-hydroxybenzoate anhydride. 1 Benzoic acid, 4-hydroxy-, N.A. Izmailov and V.S. silver salt ͑silver Chernyi, Zh. Fiz. Khim. 34,319 ͒ ͑ ͓͒ Auxiliary Information 4-hydroxybenzoate ;C7H5O3Ag; 1960 Russ. J. Phys. Chem. ͓͔ ͑Engl. Transl.͒ 34,149͑1960͔͒. ͑ ͒ ͓ ͔ Methods/Apparatus/Procedure: 2 Water; H2O; 7732-18-5 The synthetic method was used. The experimental details were given in the compilation of Ref. 62 for the lithium salicylate–water system in Sec. Variables: Prepared by: 2.3.1.1. t/ °C=25 H. Miyamoto

Source and Purity of Materials: Solubility of silver 4-hydroxybenzoate in water Rubidium salt of 4-hydroxybenzoic acid was prepared by neutralizing the acid with the corresponding hydroxide or carbonate. Rubidium carbonate Temperature Solubility was prepared from a specimen of the alum. The salt obtained was tested spectroscopically and found to be free from other alkali metals. / 3 / −1 t °C 10 m1 mol kg

Estimated Errors: 25 9.43 Nothing speciﬁed.

Auxiliary Information

Components: Original Measurements: Methods/Apparatus/Procedure: 62 ͑1͒ Benzoic acid, 4-hydroxy-, N.V. Sidgwick and E.K. The experimental detail is given in the compilation of Ref. 64 for the monocesium salt ͑cesium Ewbank, J. Chem. Soc. silver salicylate–water system of the paper by the authors in Sec. 2.3.1.1. ͒ 4-hydroxybenzoate ;C7H5O3Cs; 1922, 1844. ͓͔ Source and Purity of Materials: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 The silver salt of 4-hydroxybenzoic acid was prepared from silver nitrate labeled with radioactive 110Ag. Variables: Prepared by: t/ °C=−1.56–136.0 H. Miyamoto Estimated Errors: Solubility: relative accuracy is 1%–3 % at a conﬁdence limit of 0.95. Temperature: precision Ϯ0.5 °C. Solubility of cesium 4-hydroxybenzoate in water

Temperature Solubility

/ a t °C 100w1 100x1 Solid phase

−1.56 4.34 1.103 A 2.3.2. Dihydroxybenzoic acid salts −2.42 20.38 1.677 A −4.27b 29.57 2.723 A 3.5 29.57 2.723 B 27.5 40.80 4.395 B 2.3.2.1. 2,3-Dihydroxybenzoic acid salts 49.0 50.07 6.268 B 75.5 60.36 9.222 C Components: Original Measurements: 90.3 65.35 11.17 C ͑1͒ Cerium 65A. Kula and W. Brzyska, Polish 107.5 70.67 13.85 C 2,3-dihydroxybenzoate; J. Chem. 74,45͑2000͒. 118.0 73.84 15.84 C ͓͔ C21H15O12Ce; 136.0 79.88 20.93 C ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 a A=ice; B=cesium 4-hydroxybenzoate monohydrate; C=cesium Variables: Prepared by: 4-hydroxybenzoate anhydride. T/K=293 H. Miyamoto bMetastable point.

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Solubility of cerium 2,3-dihydroxybenzoate in water Components: Original Measurements: 65 Temperature Solubility ͑1͒ Erbium A. Kula and W. Brzyska, Polish 2,3-dihydroxybenzoate J. Chem. 74,45͑2000͒. / 3 / −3 T K10c1 mol dm tetrahydrate; C21H15O12Er·4H2O; ͓͔ 293 0.9 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Auxiliary Information T/K=293 H. Miyamoto Methods/Apparatus/Procedure: The solubility of cerium 2,3-dihydroxybenzoate in water at 293 K under Solubility of erbium 2,3-dihydroxybenzoate in water isothermal condition was determined by a Specord M-40 spectrophotometer, using arsenazo III. Temperature Solubility

Source and Purity of Materials: / 3 / −3 T K10c1 mol dm The complex of Ce͑III͒ with 2,3-dihydroxybenzoic acid was obtained by dissolving the freshly precipitated Ce͑III͒ carbonate in a solution of 293 4.0 2,3-dihydroxybenzoic acid and crystallizing at room temperature. The precipitates formed were filtered off, washed with water, and dried at Auxiliary Information 303 K to a constant mass. The composition of the prepared complex was determined by elemental analysis, by ignition of the complex to the oxide Methods/Apparatus/Procedure: and from a TG curve. The Ce͑III͒ complex was prepared as a crystalline The solubility of erbium 2,3-dihydroxybenzoate in water at 293 K under solid with a molar ratio of metal to organic ligand of 1:3 and formula isothermal condition was determined by a Specord M-40 Ce͕C H ͑OH͒ COO͖ . 6 3 2 3 spectrophotometer, using arsenazo III. Estimated Errors: Source and Purity of Materials: Nothing specified. The complex of Er͑III͒ with 2,3-dihydroxybenzoic acid was obtained by the same method as for cerium 2,3-dihydroxybenzoate using Er͑III͒ ͑ ͓ ͕ ͑ ͒ ͖ ͔ ͒ carbonate the formula of the complex: Er C6H3 OH 2COO 3 ·4H2O . Components: Original Measurements: ͑1͒ Dysprosium 65A. Kula and W. Brzyska, Polish Estimated Errors: 2,3-dihydroxybenzoate J. Chem. 74,45͑2000͒. Nothing specified. tetrahydrate; ͓͔ C21H15O12Dy·4H2O; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: ͑1͒ Europium 65A. Kula and W. Brzyska, Polish Variables: Prepared by: ͑ ͒ / 2,3-dihydroxybenzoate; J. Chem. 74,45 2000 . T K=293 H. Miyamoto ͓͔ C21H15O12Eu; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Solubility of dysprosium 2,3-dihydroxybenzoate in water Variables: Prepared by: T/K=293 H. Miyamoto Temperature Solubility

T/K103c /mol dm−3 1 Solubility of europium 2,3-dihydroxybenzoate in water 293 5.8 Temperature Solubility

/ 3 / −3 Auxiliary Information T K10c1 mol dm

Methods/Apparatus/Procedure: 293 10.3 The solubility of dysprosium 2,3-dihydroxybenzoate in water at 293 K under isothermal condition was determined by a Specord M-40 Auxiliary Information spectrophotometer, using arsenazo III. Methods/Apparatus/Procedure: Source and Purity of Materials: The solubility of europium 2,3-dihydroxybenzoate in water at 293 K ͑ ͒ The complex of Dy III with 2,3-dihydroxybenzoic acid was obtained by under isothermal condition was determined by a Specord M-40 ͑ ͒ the same method as for cerium 2,3-dihydroxybenzoate using Dy III spectrophotometer, using arsenazo III. ͑ ͓ ͕ ͑ ͒ ͖ ͔ ͒ carbonate the formula of the complex: Dy C6H3 OH 2COO 3 ·4H2O . Source and Purity of Materials: Estimated Errors: The complex of Eu͑III͒ with 2,3-dihydroxybenzoic acid was obtained by Nothing speciﬁed. the same method as for cerium 2,3-dihydroxybenzoate using Eu͑III͒ ͑ ͕ ͑ ͒ ͖ ͒ carbonate the formula of the complex: Eu C6H3 OH 2COO 3 .

Estimated Errors: Nothing speciﬁed.

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Components: Original Measurements: Components: Original Measurements: ͑1͒ Gadolinium 65A. Kula and W. Brzyska, Polish ͑1͒ Neodymium 65A. Kula and W. Brzyska, Polish 2,3-dihydroxybenzoate; J. Chem. 74,45͑2000͒. 2,3-dihydroxybenzoate; J. Chem. 74,45͑2000͒. ͓͔ ͓͔ C21H15O12Gd; C21H15O12Nd; ͑ ͒ ͓ ͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 2 Water; H2O; 7732-18-5

Variables: Prepared by: Variables: Prepared by: T/K=293 H. Miyamoto T/K=293 H. Miyamoto

Solubility of gadolinium 2,3-dihydroxybenzoate in water Solubility of neodymium 2,3-dihydroxybenzoate in water

Temperature Solubility Temperature Solubility

/ 3 / −3 / 3 / −3 T K10c1 mol dm T K10c1 mol dm

293 9.7 293 2.8

Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: The solubility of gadolinium 2,3-dihydroxybenzoate in water at 293 K The solubility of neodymium 2,3-dihydroxybenzoate in water at 293 K under isothermal condition was determined by a Specord M-40 under isothermal condition was determined by a Specord M-40 spectrophotometer, using arsenazo III. spectrophotometer, using arsenazo III.

Source and Purity of Materials: Source and Purity of Materials: The complex of Gd͑III͒ with 2,3-dihydroxybenzoic acid was obtained by The complex of Nd͑III͒ with 2,3-dihydroxybenzoic acid was obtained by the same method as for cerium 2,3-dihydroxybenzoate using Gd͑III͒ the same method as for cerium 2,3-dihydroxybenzoate using Nd͑III͒ ͑ ͕ ͑ ͒ ͖ ͒ ͑ ͕ ͑ ͒ ͖ ͒ carbonate the formula of the complex: Gd C6H3 OH 2COO 3 . carbonate the formula of the complex: Nd C6H3 OH 2COO 3 .

Estimated Errors: Estimated Errors: Nothing speciﬁed. Nothing speciﬁed.

Components: Original Measurements: Components: Original Measurements: 65 ͑1͒ Holmium A. Kula and W. Brzyska, Polish ͑1͒ Lanthanum 65A. Kula and W. Brzyska, Polish 2,3-dihydroxybenzoate J. Chem. 74,45͑2000͒. 2,3-dihydroxybenzoate; J. Chem. 74,45͑2000͒. ͓͔ tetrahydrate; C21H15O12La; ͓͔ ͑ ͒ ͓ ͔ C21H15O12Ho·4H2O; 2 Water; H2O; 7732-18-5 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Variables: Prepared by: Variables: Prepared by: T/K=293 H. Miyamoto T/K=293 H. Miyamoto

Solubility of lanthanum 2,3-dihydroxybenzoate in water Solubility of holmium 2,3-dihydroxybenzoate in water Temperature Solubility Temperature Solubility / 3 / −3 T K10c1 mol dm / 3 / −3 T K10c1 mol dm 293 1.0 293 4.7

Auxiliary Information Auxiliary Information Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: The solubility of lanthanum 2,3-dihydroxybenzoate in water at 293 K The solubility of holmium 2,3-dihydroxybenzoate in water at 293 K under under isothermal condition was determined by a Specord M-40 isothermal condition was determined by a Specord M-40 spectrophotometer, using arsenazo III. spectrophotometer, using arsenazo III. Source and Purity of Materials: Source and Purity of Materials: The complex of La͑III͒ with 2,3-dihydroxybenzoic acid was obtained by The complex of Ho͑III͒ with 2,3-dihydroxybenzoic acid was obtained by the same method as for cerium 2,3-dihydroxybenzoate using La͑III͒ the same method as for cerium 2,3-dihydroxybenzoate using Ho͑III͒ carbonate ͑the formula of the complex: La͕C H ͑OH͒ COO͖ ͒. ͑ ͓ ͕ ͑ ͒ ͖ ͔ ͒ 6 3 2 3 carbonate the formula of the complex: Ho C6H3 OH 2COO 3 ·4H2O . Estimated Errors: Estimated Errors: Nothing speciﬁed. Nothing speciﬁed.

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Components: Original Measurements: Components: Original Measurements: ͑1͒ Lutetium 65A. Kula and W. Brzyska, Polish ͑1͒ Samarium 65A. Kula and W. Brzyska, Polish 2,3-dihydroxybenzoate dihydrate; J. Chem. 74,45͑2000͒. 2,3-dihydroxybenzoate; J. Chem. 74,45͑2000͒. ͓͔ ͓͔ C21H15O12Lu·2H2O; C21H15O12Sm; ͑ ͒ ͓ ͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 2 Water; H2O; 7732-18-5

Variables: Prepared by: Variables: Prepared by: T/K=293 H. Miyamoto T/K=293 H. Miyamoto

Solubility of lutetium 2,3-dihydroxybenzoate in water Solubility of samarium 2,3-dihydroxybenzoate in water

Temperature Solubility Temperature Solubility

/ 3 / −3 / 3 / −3 T K10c1 mol dm T K10c1 mol dm

293 3.4 293 4.3

Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: The solubility of lutetium 2,3-dihydroxybenzoate in water at 293 K under The solubility of samarium 2,3-dihydroxybenzoate in water at 293 K isothermal condition was determined by a Specord M-40 under isothermal condition was determined by a Specord M-40 spectrophotometer, using arsenazo III. spectrophotometer, using arsenazo III.

Source and Purity of Materials: Source and Purity of Materials: The complex of Lu͑III͒ with 2,3-dihydroxybenzoic acid was obtained by The complex of Sm͑III͒ with 2,3-dihydroxybenzoic acid was obtained by the same method as for cerium 2,3-dihydroxybenzoate using Lu͑III͒ the same method as for cerium 2,3-dihydroxybenzoate using Sm͑III͒ ͑ ͓ ͕ ͑ ͒ ͖ ͔ ͒ ͑ ͕ ͑ ͒ ͖ ͒ carbonate the formula of the complex: Lu C6H3 OH 2COO 3 ·2H2O . carbonate the formula of the complex: Sm C6H3 OH 2COO 3 .

Estimated Errors: Estimated Errors: Nothing speciﬁed. Nothing speciﬁed.

Components: Original Measurements: Components: Original Measurements: ͑1͒ Praseodymium 65A. Kula and W. Brzyska, Polish ͑1͒ Terbium 65A. Kula and W. Brzyska, Polish 2,3-dihydroxybenzoate; J. Chem. 74,45͑2000͒. 2,3-dihydroxybenzoate; J. Chem. 74,45͑2000͒. ͓͔ ͓͔ C21H15O12Pr; C21H15O12Tb; ͑ ͒ ͓ ͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 2 Water; H2O; 7732-18-5

Variables: Prepared by: Variables: Prepared by: T/K=293 H. Miyamoto T/K=293 H. Miyamoto

Solubility of praseodymium 2,3-dihydroxybenzoate in water Solubility of terbium 2,3-dihydroxybenzoate in water

Temperature Solubility Temperature Solubility

/ 3 / −3 / 3 / −3 T K10c1 mol dm T K10c1 mol dm

293 4.9 293 7.4

Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: The solubility of praseodymium 2,3-dihydroxybenzoate in water at 293 K The solubility of terbium 2,3-dihydroxybenzoate in water at 293 K under under isothermal condition was determined by a Specord M-40 isothermal condition was determined by a Specord M-40 spectrophotometer, using arsenazo III. spectrophotometer, using arsenazo III.

Source and Purity of Materials: Source and Purity of Materials: The complex of Pr͑III͒ with 2,3-dihydroxybenzoic acid was obtained by The complex of Tb͑III͒ with 2,3-dihydroxybenzoic acid was obtained by the same method as for cerium 2,3-dihydroxybenzoate using Pr͑III͒ the same method as for cerium 2,3-dihydroxybenzoate using Tb͑III͒ ͑ ͕ ͑ ͒ ͖ ͒ ͑ ͕ ͑ ͒ ͖ ͒ carbonate the formula of the complex: Pr C6H3 OH 2COO 3 . carbonate the formula of the complex: Tb C6H3 OH 2COO 3 .

Estimated Errors: Estimated Errors: Nothing speciﬁed. Nothing speciﬁed.

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Components: Original Measurements: Components: Original Measurements: ͑1͒ Thulium 65A. Kula and W. Brzyska, Polish ͑1͒ Yttrium 65A. Kula and W. Brzyska, Polish 2,3-dihydroxybenzoate J. Chem. 74,45͑2000͒. 2,3-dihydroxybenzoate J. Chem. 74,45͑2000͒.

tetrahydrate; tetrahydrate; C21H15O12Y·4H2O; ͓͔ ͓͔ C21H15O12Tm·4H2O; ͑ ͒ ͓ ͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 2 Water; H2O; 7732-18-5

Variables: Prepared by: Variables: Prepared by: T/K=293 H. Miyamoto T/K=293 H. Miyamoto

Solubility of thulium 2,3-dihydroxybenzoate in water Solubility of yttrium 2,3-dihydroxybenzoate in water

Temperature Solubility Temperature Solubility

/ 3 / −3 T/ 3c / −3 T K10c1 mol dm K101 mol dm

293 4.3 293 6.5

Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: The solubility of thulium 2,3-dihydroxybenzoate in water at 293 K under The solubility of yttrium 2,3-dihydroxybenzoate in water at 293 K under isothermal condition was determined by a Specord M-40 isothermal condition was determined by a Specord M-40 spectrophotometer, using arsenazo III. spectrophotometer, using arsenazo III.

Source and Purity of Materials: Source and Purity of Materials: ͑ ͒ The complex of Tm͑III͒ with 2,3-dihydroxybenzoic acid was obtained by The complex of Y III with 2,3-dihydroxybenzoic acid was obtained by ͑ ͒ the same method as for cerium 2,3-dihydroxybenzoate using Tm͑III͒ the same method as for cerium 2,3-dihydroxybenzoate using Y III ͑ ͓ ͕ ͑ ͒ ͖ ͔ ͒ ͑ ͓ ͕ ͑ ͒ ͖ ͔ ͒ carbonate the formula of the complex: Y C6H3 OH 2COO 3 ·4H2O . carbonate the formula of the complex: Tm C6H3 OH 2COO 3 ·4H2O .

Estimated Errors: Estimated Errors: Nothing speciﬁed. Nothing speciﬁed.

Components: Original Measurements: ͑1͒ Ytterbium 65A. Kula and W. Brzyska, Polish 2,3-dihydroxybenzoate dihydrate; J. Chem. 74,45͑2000͒. ͓͔ 2.3.2.2. 2,4-Dihydroxybenzoic acid salts C21H15O12Yb·2H2O; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: Variables: Prepared by: ͑1͒ Cerium, 66W. Brzyska and A. Kula, T/K=293 H. Miyamoto tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211,199 dihydrate, ͑OC-6-11͒- ͑cerium ͑1992͒. Solubility of ytterbium 2,3-dihydroxybenzoate in water 2,4-dihydroxybenzoate ͒ dihydrate ;C21H15CeO12 ·2H2O; Temperature Solubility ͓146716-20-3͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 3 / −3 T K10c1 mol dm Variables: Prepared by: 293 3.0 T/K=293 H. Miyamoto

Auxiliary Information Solubility of cerium 2,4-dihydroxybenzoate in water

Methods/Apparatus/Procedure: Temperature Solubility The solubility of ytterbium 2,3-dihydroxybenzoate in water at 293 K / 2 / −3 under isothermal condition was determined by a Specord M-40 T K10c1 mol dm spectrophotometer, using arsenazo III. 293 0.56 Source and Purity of Materials: ͑ ͒ The complex of Yb III with 2,3-dihydroxybenzoic acid was obtained by Auxiliary Information the same method as for cerium 2,3-dihydroxybenzoate using Yb͑III͒ ͑ ͓ ͕ ͑ ͒ ͖ ͔ ͒ carbonate the formula of the complex: Yb C6H3 OH 2COO 3 ·2H2O . Methods/Apparatus/Procedure: The solubility of cerium 2,4-dihydroxybenzoate in water at 293 K was Estimated Errors: gravimetrically determined by measuring the concentration of Ce͑III͒ in Nothing speciﬁed. the saturated solution by the oxalate method.

J. Phys. Chem. Ref. Data, Vol. 40, No. 1, 2011

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Source and Purity of Materials: Solubility of erbium 2,4-dihydroxybenzoate in water Cerium 2,4-hydroxybenzoate was prepared by addition of an equivalent quantity of ammonium 2,4-hydroxybenzoate ͑pH 5.0͒ to a hot solution Temperature Solubility containing cerium nitrate. The precipitates formed were ﬁltered off, / 2 / −3 washed with methanol, and dried at 303 K to a constant mass. The T K10c1 mol dm quantitative compositions of the prepared complex were determined by 293 4.81 elemental analysis. The crystallization water was determined from the TG curve. The complex was obtained as solid with a molar ratio of metal to ͓ ͕ ͑ ͒ ͖ ͔ organic ligand of 1:3 and formula Ce C6H3 OH 2COO 3 ·2H2O. Auxiliary Information

Estimated Errors: Methods/Apparatus/Procedure: Nothing speciﬁed. The solubility of erbium 2,4-dihydroxybenzoate in water at 293 K was gravimetrically determined by measuring the concentration of Er͑III͒ in the saturated solution by the oxalate method. Components: Original Measurements: Source and Purity of Materials: ͑1͒ Dysprosium, tris͑2,4- 66W. Brzyska and A. Kula, dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211, 199 Erbium 2,4-dihydroxybenzoate was prepared by the same method as for ͑ tetrahydrate, ͑OC-6-11͒- ͑1992͒. cerium 2,4-dihydroxybenzoate using erbium chloride the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ ͑dysprosium complex: Er C6H3 OH 2COO 3 ·H2O . 2,4-dihydroxybenzoate Estimated Errors: tetrahydrate͒; Nothing speciﬁed. C21H15DyO12 ·4H2O; ͓146716-26-9͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: Variables: Prepared by: ͑1͒ Europium 66W. Brzyska and A. Kula, / T K=293 H. Miyamoto tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211,199 dihydrate, ͑OC-6-11͒- ͑europium ͑1992͒. 2,4-dihydroxybenzoate Solubility of dysprosium 2,4-dihydroxybenzoate in water ͒ dihydrate ;C21H15EuO12 ·2H2O; ͓196716-24-7͔ Temperature Solubility ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 T/K102c /mol dm−3 1 Variables: Prepared by: / 293 3.94 T K=293 H. Miyamoto

Auxiliary Information Solubility of europium 2,4-dihydroxybenzoate in water

Methods/Apparatus/Procedure: Temperature Solubility The solubility of dysprosium 2,4-dihydroxybenzoate in water at 293 K / 2 / −3 was gravimetrically determined by measuring the concentration of Dy͑III͒ T K10c1 mol dm in the saturated solution by the oxalate method. 293 1.16 Source and Purity of Materials: Dysprosium 2,4-dihydroxybenzoate was prepared by the same method as Auxiliary Information for cerium 2,4-dihydroxybenzoate using dysprosium chloride ͑the formula ͓ ͕ ͑ ͒ ͖ ͔ ͒ of the complex: Dy C6H3 OH 2COO 3 ·4H2O . Methods/Apparatus/Procedure: The solubility of europium 2,4-dihydroxybenzoate in water at 293 K was Estimated Errors: gravimetrically determined by measuring the concentration of Eu͑III͒ in Nothing speciﬁed. the saturated solution by the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Europium 2,4-dihydroxybenzoate was prepared by the same method as for ͑ ͑1͒ Erbium, 66W. Brzyska and A. Kula, cerium 2,4-dihydroxybenzoate using europium chloride the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211, 199 complex: Eu C6H3 OH 2COO 3 ·2H2O . tetrahydrate, ͑OC-6-11͒- ͑erbium ͑1992͒. Estimated Errors: 2,4-dihydroxybenzoate Nothing speciﬁed. tetrahydrate͒;

C21H15ErO12 ·4H2O; ͓146716-28-1͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: T/K=293 H. Miyamoto

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Source and Purity of Materials: Components: Original Measurements: Holmium 2,4-dihydroxybenzoate was prepared by the same method as for 66 ͑1͒ Gadolinium, W. Brzyska and A. Kula, cerium 2,4-dihydroxybenzoate using holmium chloride ͑the formula of the tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211, 199 ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Ho C6H3 OH 2COO 3 ·4H2O . dihydrate, ͑OC-6-11͒- ͑1992͒. ͑gadolinium Estimated Errors: 2,4-dihydroxybenzoate Nothing speciﬁed. ͒ dihydrate ;C21H15GdO12 ·2H2O; ͓͔ ͑2͒ Water; H O; ͓7732-18-5͔ 2 Components: Original Measurements: 66 Variables: Prepared by: ͑1͒ Neodymium, W. Brzyska and A. Kula, ͑ T/K=293 H. Miyamoto tris 2,4-dihydroxybenzoato Thermochim. Acta 211,199 ͑O1 ,O1Ј͒ dihydrate, ͑OC-6-11͒- ͑1992͒. ͑neodymium Solubility of gadolinium 2,4-dihydroxybenzoate in water 2,4-dihydroxybenzoate ͒ dihydrate ;C21H15O12Nd·2H2O; Temperature Solubility ͓146716-22-5͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 2 / −3 T K10c1 mol dm Variables: Prepared by: 293 1.51 T/K=293 H. Miyamoto

Auxiliary Information Solubility of neodymium 2,4-dihydroxybenzoate in water

Methods/Apparatus/Procedure: Temperature Solubility The solubility of gadolinium 2,4-dihydroxybenzoate in water at 293 K ͑ ͒ / 2 / −3 was gravimetrically determined by measuring the concentration of Gd III T K10c1 mol dm in the saturated solution by the oxalate method. 293 0.62 Source and Purity of Materials: Gadolinium 2,4-dihydroxybenzoate was prepared by the same method as for cerium 2,4-dihydroxybenzoate using gadolinium chloride ͑the formula Auxiliary Information of the complex: ͓Gd͕C H ͑OH͒ COO͖ ͔·2H O͒. 6 3 2 3 2 Methods/Apparatus/Procedure: Estimated Errors: The solubility of neodymium 2,4-dihydroxybenzoate in water at 293 K ͑ ͒ Nothing speciﬁed. was gravimetrically determined by measuring the concentration of Nd III in the saturated solution by the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Neodymium 2,4-dihydroxybenzoate was prepared by the same method as ͑1͒ Holmium, 66W. Brzyska and A. Kula, for cerium 2,4-dihydroxybenzoate using neodymium chloride ͑the formula ͑ ͓ ͕ ͑ ͒ ͖ ͔ ͒ tris 2,4-dihydroxybenzoato Thermochim. Acta 211, 199 of the complex: Er C6H3 OH 2COO 3 ·4H2O . ͑O1 ,O1Ј͒ tetrahydrate, ͑1992͒. ͑OC-6-11͒- ͑holmium Estimated Errors: 2,4-dihydroxybenzoate Nothing speciﬁed. tetrahydrate͒;

C21H15HoO12 ·4H2O; ͓ ͔ 146716-27-0 Components: Original Measurements: ͑2͒ Water; H O; ͓7732-18-5͔ 66 2 ͑1͒ Lanthanum, W. Brzyska and A. Kula, ͑ ͑ 1 1Ј͒ Variables: Prepared by: tris 2,4-dihydroxybenzoato- O ,O Thermochim. Acta 211,199 dihydrate, ͑OC-6-11͒- ͑1992͒. T/K=293 H. Miyamoto ͑lanthanum 2,4-dihydroxybenzoate ͒ Solubility of holmium 2,4-dihydroxybenzoate in water dihydrate ;C21H15LaO12 ·2H2O; ͓146734-35-2͔ ͑ ͒ ͓ ͔ Temperature Solubility 2 Water; H2O; 7732-18-5

/ 2 / −3 Variables: Prepared by: T K10c1 mol dm T/K=293 H. Miyamoto 293 3.85

Solubility of lanthanum 2,4-dihydroxybenzoate in water Auxiliary Information Temperature Solubility Methods/Apparatus/Procedure: / 2 / −3 The solubility of holmium 2,4-dihydroxybenzoate in water at 293 K was T K10c1 mol dm gravimetrically determined by measuring the concentration of Ho͑III͒ in the saturated solution by the oxalate method. 293 0.67

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Auxiliary Information Solubility of praseodymium 2,4-dihydroxybenzoate in water

Methods/Apparatus/Procedure: Temperature Solubility The solubility of lanthanum 2,4-dihydroxybenzoate in water at 293 K was / 2 / −3 gravimetrically determined by measuring the concentration of La͑III͒ in T K10c1 mol dm the saturated solution by the oxalate method. 293 0.58 Source and Purity of Materials: Lanthanum 2,4-dihydroxybenzoate was prepared by the same method as Auxiliary Information for cerium 2,4-dihydroxybenzoate using lanthanum chloride ͑the formula ͓ ͕ ͑ ͒ ͖ ͔ ͒ of the complex: La C6H3 OH 2COO 3 ·2H2O . Methods/Apparatus/Procedure: Estimated Errors: The solubility of praseodymium 2,4-dihydroxybenzoate in water at 293 K was gravimetrically determined by measuring the concentration of Pr͑III͒ Nothing speciﬁed. in the saturated solution by the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Praseodymium 2,4-dihydroxybenzoate was prepared by the same method ͑1͒ Lutetium, 66W. Brzyska and A. Kula, as for cerium 2,4-dihydroxybenzoate using praseodymium chloride ͑the 1 1 ͓ ͕ ͑ ͒ ͖ ͔ ͒ tris͑2,4-dihydroxybenzoato-͑O ,O Ј͒ Thermochim. Acta 211, 199 formula of the complex: Pr C6H3 OH 2COO 3 ·2H2O . tetrahydrate, ͑OC-6-11͒- ͑1992͒. ͑lutetium 2,4-dihydroxybenzoate Estimated Errors: tetrahydrate͒; Nothing speciﬁed.

C21H15O12Lu·4H2O; ͓146716-31-6͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: ͑1͒ Samarium, 66W. Brzyska and A. Kula, Variables: Prepared by: tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211,199 T/K=293 H. Miyamoto dihydrate, ͑OC-6-11͒- ͑samarium ͑1992͒. 2,4-dihydroxybenzoate ͒ Solubility of lutetium 2,4-dihydroxybenzoate in water dihydrate ;C21H15O12Sm·2H2O; ͓146716-23-6͔ ͑ ͒ ͓ ͔ Temperature Solubility 2 Water; H2O; 7732-18-5

/ 2 / −3 Variables: Prepared by: T K10c1 mol dm T/K=293 H. Miyamoto 293 16.12

Solubility of samarium 2,4-dihydroxybenzoate in water Auxiliary Information Temperature Solubility Methods/Apparatus/Procedure: / 2 / −3 The solubility of lutetium 2,4-dihydroxybenzoate in water at 293 K was T K10c1 mol dm gravimetrically determined by measuring the concentration of Lu͑III͒ in the saturated solution by the oxalate method. 293 0.82

Source and Purity of Materials: Auxiliary Information Lutetium 2,4-dihydroxybenzoate was prepared by the same method as for ͑ cerium 2,4-dihydroxybenzoate using lutetium chloride the formula of the Methods/Apparatus/Procedure: complex: ͓Lu͕C H ͑OH͒ COO͖ ͔·4H O͒. 6 3 2 3 2 The solubility of samarium 2,4-dihydroxybenzoate in water at 293 K was ͑ ͒ Estimated Errors: gravimetrically determined by measuring the concentration of Sm III in the saturated solution by the oxalate method. Nothing speciﬁed. Source and Purity of Materials: Samarium 2,4-dihydroxybenzoate was prepared by the same method as for Components: Original Measurements: cerium 2,4-dihydroxybenzoate using samarium chloride ͑the formula of 66 ͓ ͕ ͑ ͒ ͖ ͔ ͒ ͑1͒ Praseodymium, W. Brzyska and A. Kula, the complex: Sm C6H3 OH 2COO 3 ·2H2O . tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211, 199 dihydrate, ͑OC-6-11͒- ͑1992͒. Estimated Errors: ͑praseodymium Nothing speciﬁed. 2,4-dihydroxybenzoate ͒ dihydrate ;C21H15O12Pr·2H2O; ͓146716-21-4͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: T/K=293 H. Miyamoto

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Source and Purity of Materials: Components: Original Measurements: Thulium 2,4-dihydroxybenzoate was prepared by the same method as for 66 ͑1͒ Terbium, W. Brzyska and A. Kula, cerium 2,4-dihydroxybenzoate using thulium chloride ͑the formula of the tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211, 199 ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Tm C6H3 OH 2COO 3 ·4H2O . tetrahydrate, ͑OC-6-11͒- ͑terbium ͑1992͒. 2,4-dihydroxybenzoate Estimated Errors: tetrahydrate͒; Nothing speciﬁed. C21H15O12Tb·4H2O; ͓146734-36-3͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: ͑ ͒ 66 Variables: Prepared by: 1 Ytterbium, W. Brzyska and A. Kula, tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211,199 T/K=293 H. Miyamoto tetrahydrate, ͑OC-6-11͒- ͑1992͒. ͑ytterbium 2,4-dihydroxybenzoate Solubility of terbium 2,4-dihydroxybenzoate in water tetrahydrate͒; C21H15O12Yb·4H2O; Temperature Solubility ͓146716-30-5͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 2 / −3 T K10c1 mol dm Variables: Prepared by: 293 2.82 T/K=293 H. Miyamoto

Auxiliary Information Solubility of ytterbium 2,4-dihydroxybenzoate in water

Methods/Apparatus/Procedure: Temperature Solubility The solubility of terbium 2,4-dihydroxybenzoate in water at 293 K was / 2 / −3 gravimetrically determined by measuring the concentration of Tb͑III͒ in T K10c1 mol dm the saturated solution by the oxalate method. 293 18.17 Source and Purity of Materials: Terbium 2,4-dihydroxybenzoate was prepared by the same method as for Auxiliary Information cerium 2,4-dihydroxybenzoate using terbium chloride ͑the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Tb C6H3 OH 2COO 3 ·4H2O . Methods/Apparatus/Procedure: The solubility of ytterbium 2,4-dihydroxybenzoate in water at 293 K was Estimated Errors: gravimetrically determined by measuring the concentration of Yb͑III͒ in Nothing speciﬁed. the saturated solution by the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Ytterbium 2,4-dihydroxybenzoate was prepared by the same method as for ͑ ͑1͒ Thulium, 66W. Brzyska and A. Kula, cerium 2,4-dihydroxybenzoate using ytterbium chloride the formula of ͓ ͕ ͑ ͒ ͖ ͔ ͒ tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211, 199 the complex: Yb C6H3 OH 2COO 3 ·4H2O . tetrahydrate, ͑OC-6-11͒- ͑thulium ͑1992͒. Estimated Errors: 2,4-dihydroxybenzoate Nothing speciﬁed. tetrahydrate͒;

C21H15O12Tm·4H2O; ͓146716-29-2͔ ͑ ͒ ͓ ͔ Components: Original Measurements: 2 Water; H2O; 7732-18-5 ͑1͒ Yttrium, 66W. Brzyska and A. Kula, Variables: Prepared by: tris͑2,4-dihydroxybenzoato-͑O1 ,O1Ј͒ Thermochim. Acta 211,199 T/K=293 H. Miyamoto tetrahydrate, ͑OC-6-11͒- ͑yttrium ͑1992͒. 2,4-dihydroxybenzoate ͒ tetrahydrate ;C21H15O12Y·4H2O; Solubility of thulium 2,4-dihydroxybenzoate in water ͓146716-19-0͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Temperature Solubility Variables: Prepared by: / 2 / −3 T K10c1 mol dm T/K=293 H. Miyamoto 293 9.84 Solubility of yttrium 2,4-dihydroxybenzoate in water

Auxiliary Information Temperature Solubility

Methods/Apparatus/Procedure: / 2 / −3 T K10c1 mol dm The solubility of thulium 2,4-dihydroxybenzoate in water at 293 K was gravimetrically determined by measuring the concentration of Tm͑III͒ in 293 3.98 the saturated solution by the oxalate method.

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Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Dysprosium, 67W. Brzyska and A. Kula, J. The solubility of yttrium 2,4-dihydroxybenzoate in water at 293 K was tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53,161 gravimetrically determined by measuring the concentration of Y͑III͒ in the ␬OЈ͒, ͑OC-6-11͒- ͑dysprosium ͑1998͒. saturated solution by the oxalate method. 2,5-dihydroxybenzoate͒; ͓ ͔ C21H15DyO12; 217952-77-7 ͑ ͒ ͓ ͔ Source and Purity of Materials: 2 Water; H2O; 7732-18-5 Yttrium 2,4-dihydroxybenzoate was prepared by the same method as for cerium 2,4-dihydroxybenzoate using yttrium chloride ͑the formula of the Variables: Prepared by: ͓ ͕ ͑ ͒ ͖ ͔ ͒ / complex: Y C6H3 OH 2COO 3 ·4H2O . T K=293 H. Miyamoto

Estimated Errors: Nothing speciﬁed. Solubility of dysprosium 2,5-dihydroxybenzoate in water

Temperature Solubility

/ 2 / −3 T K10c1 mol dm

293 4.07 2.3.2.3. 2,5-Dihydroxybenzoic acid salts Auxiliary Information

Components: Original Measurements: Method/Apparatus/Procedure: ͑ ͒ 67 1 Cerium, W. Brzyska and A. Kula, J. Isothermal method was used. After equilibrium had been established, ͑ ␬ tris 2,5-dihydroxybenzoato- O, Therm. Anal. Calorim. 53, 161 samples of 2 and 5 cm3 were withdrawn and the concentration of Dy͑III͒ ␬ Ј͒ ͑ ͒ ͑ ͑ ͒ O , OC-6-11 - cerium 1998 . ions was determined gravimetrically using the oxalate method. 2,5-dihydroxybenzoate͒; ͓ ͔ C21H15O12Ce; 217952-70-0 Source and Purity of Materials: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Dysprosium 2,5-dihydroxybenzoate was prepared by the same method as for cerium 2,5-dihydroxybenzoate using Dy͑III͒ hydroxide or carbonate Variables: Prepared by: ͑ ͕ ͑ ͒ ͖ ͒ the formula of the complex: Dy C6H3 OH 2COO 3 . T/K=293 H. Miyamoto Estimated Errors: Nothing speciﬁed. Solubility of cerium 2,5-dihydroxybenzoate in water

Temperature Solubility Components: Original Measurements: / 2 / −3 67 T K10c1 mol dm ͑1͒ Erbium, W. Brzyska and A. Kula, J. tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53,161 293 0.99 ␬OЈ͒, ͑OC-6-11͒- ͑erbium ͑1998͒. 2,5-dihydroxybenzoate͒; ͓ ͔ Auxiliary Information C21H15ErO12; 217952-79-9 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Method/Apparatus/Procedure: Variables: Prepared by: Isothermal method was used. After equilibrium had been established, / samples of 2 and 5 cm3 were withdrawn and the concentration of Ce͑III͒ T K=293 H. Miyamoto ions was determined gravimetrically using the oxalate method. Solubility of erbium 2,5-dihydroxybenzoate in water Source and Purity of Materials: Cerium 2,5-dihydroxybenzoate was prepared by dissolving freshly Temperature Solubility precipitated cerium hydroxide or carbonate in a solution of 2,5-dihydroxybenzoic acid and crystallization at room temperature. The / 2 / −3 T K10c1 mol dm precipitate formed was ﬁltered off, washed with water and methanol, and dried at 303 K to a constant mass. The compositions of the prepared 293 4.44 complex were determined by elemental analysis. The complex was prepared as a solid with a molar ratio of metal to organic ligand of 1:3 ͕ ͑ ͒ ͖ Auxiliary Information and formula Ce C6H3 OH 2COO 3.

Estimated Errors: Method/Apparatus/Procedure: Nothing speciﬁed. Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Er͑III͒ ions was determined gravimetrically using the oxalate method.

Source and Purity of Materials: Erbium 2,5-dihydroxybenzoate was prepared by the same method as for cerium 2,5-dihydroxybenzoate using erbium hydroxide or carbonate ͑the ͕ ͑ ͒ ͖ ͒ formula of the complex: Er C6H3 OH 2COO 3 .

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Estimated Errors: Source and Purity of Materials: Nothing speciﬁed. Gadolinium 2,5-dihydroxybenzoate was prepared by the same method as for cerium 2,5-dihydroxybenzoate using gadolinium hydroxide or ͑ ͕ ͑ ͒ ͖ ͒ carbonate the formula of the complex: Gd C6H3 OH 2COO 3 .

Components: Original Measurements: Estimated Errors: ͑ ͒ 67 1 Europium, tris W. Brzyska and A. Kula, J. Nothing speciﬁed. ͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53, 161 ␬OЈ͒, ͑OC-6-11͒- ͑europium ͑1998͒. 2,5-dihydroxybenzoate͒; ͓ ͔ Components: Original Measurements: C21H15EuO12; 217952-74-4 ͑ ͒ ͓ ͔ ͑ ͒ 67 2 Water; H2O; 7732-18-5 1 Holmium, W. Brzyska and A. Kula, J. tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53,161 Variables: Prepared by: ␬OЈ͒, ͑OC-6-11͒- ͑holmium ͑1998͒. T/K=293 H. Miyamoto 2,5-dihydroxybenzoate͒; ͓ ͔ C21H15HoO12; 217952-78-8 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Solubility of europium 2,5-dihydroxybenzoate in water Variables: Prepared by: Temperature Solubility T/K=293 H. Miyamoto

/ 2 / −3 T K10c1 mol dm Solubility of holmium 2,5-dihydroxybenzoate in water 293 1.87 Temperature Solubility

Auxiliary Information / 2 / −3 T K10c1 mol dm

Method/Apparatus/Procedure: 293 3.23 Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Eu͑III͒ ions was determined gravimetrically using the oxalate method. Auxiliary Information

Source and Purity of Materials: Method/Apparatus/Procedure: Europium 2,5-dihydroxybenzoate was prepared by the same method as for Isothermal method was used. After equilibrium had been established, cerium 2,5-dihydroxybenzoate using europium hydroxide or carbonate ͑the samples of 2 and 5 cm3 were withdrawn and the concentration of Ho͑III͒ ͕ ͑ ͒ ͖ ͒ formula of the complex: Eu C6H3 OH 2COO 3 . ions was determined gravimetrically using the oxalate method.

Estimated Errors: Source and Purity of Materials: Nothing speciﬁed. Holmium 2,5-dihydroxybenzoate was prepared by the same method as for cerium 2,5-dihydroxybenzoate using holmium hydroxide or carbonate ͑the ͕ ͑ ͒ ͖ ͒ formula of the complex: Ho C6H3 OH 2COO 3 .

Components: Original Measurements: Estimated Errors: ͑ ͒ 67 1 Gadolinium, W. Brzyska and A. Kula, J. Nothing speciﬁed. tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53, 161 ␬OЈ͒, ͑OC-6-11͒- ͑gadolinium ͑1998͒. 2,5-dihydroxybenzoate͒; ͓ ͔ Components: Original Measurements: C21H15GdO12; 217952-75-5 ͑ ͒ ͓ ͔ ͑ ͒ 67 2 Water; H2O; 7732-18-5 1 Lanthanum, W. Brzyska and A. Kula, J. tris͑2,5-dihydroxybenzoato- ␬O, Therm. Anal. Calorim. 53,161 Variables: Prepared by: ␬OЈ͒, ͑OC-6-11͒- ͑lanthanum ͑1998͒. T/K=293 H. Miyamoto 2,5-dihydroxybenzoate͒; ͓ ͔ C21H15O12La; 217952-69-7 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Solubility of gadolinium 2,5-dihydroxybenzoate in water Variables: Prepared by: Temperature Solubility T/K=293 H. Miyamoto

/ 2 / −3 T K10c1 mol dm Solubility of lanthanum 2,5-dihydroxybenzoate in water 293 3.36 Temperature Solubility

Auxiliary Information / 2 / −3 T K10c1 mol dm

Method/Apparatus/Procedure: 293 1.29 Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Gd͑III͒ ions was determined gravimetrically using the oxalate method.

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Auxiliary Information Solubility of neodymium 2,5-dihydroxybenzoate in water

Method/Apparatus/Procedure: Temperature Solubility Isothermal method was used. After equilibrium had been established, 3 / 2 / −3 samples of 2 and 5 cm were withdrawn and the concentration of La͑III͒ T K10c1 mol dm ions was determined gravimetrically using the oxalate method. 293 2.44 Source and Purity of Materials: Lanthanum 2,5-dihydroxybenzoate was prepared by the same method as Auxiliary Information for cerium 2,5-dihydroxybenzoate using lanthanum hydroxide or carbonate ͑ ͕ ͑ ͒ ͖ ͒ the formula of the complex: La C6H3 OH 2COO 3 . Method/Apparatus/Procedure: Estimated Errors: Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Nd͑III͒ Nothing speciﬁed. ions was determined gravimetrically using the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Neodymium 2,5-dihydroxybenzoate was prepared by the same method as ͑1͒ Lutetium, 67W. Brzyska and A. Kula, J. for cerium 2,5-dihydroxybenzoate using neodymium hydroxide or ͑ ͕ ͑ ͒ ͖ ͒ tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53, 161 carbonate the formula of the complex: Nd C6H3 OH 2COO 3 . ␬OЈ͒, ͑OC-6-11͒- ͑lutetium ͑1998͒. 2,5-dihydroxybenzoate͒; Estimated Errors: ͓ ͔ Nothing speciﬁed. C21H15LuO12; 217952-82-4 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Components: Original Measurements: T/K=293 H. Miyamoto ͑1͒ Praseodymium, 67W. Brzyska and A. Kula, J. tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53,161 Solubility of lutetium 2,5-dihydroxybenzoate in water ␬OЈ͒, ͑OC-6-11͒- ͑1998͒. ͑praseodymium ͒ Temperature Solubility 2,5-dihydroxybenzoate ; ͓ ͔ C21H15O12Pr; 217952-71-1 / 2 / −3 ͑ ͒ ͓ ͔ T K10c1 mol dm 2 Water; H2O; 7732-18-5

293 2.66 Variables: Prepared By: T/K=293 H. Miyamoto

Auxiliary Information Solubility of praseodymium 2,5-dihydroxybenzoate in water Method/Apparatus/Procedure: Isothermal method was used. After equilibrium had been established, Temperature Solubility samples of 2 and 5 cm3 were withdrawn and the concentration of Lu͑III͒ / 2 / −3 ions was determined gravimetrically using the oxalate method. T K10c1 mol dm

Source and Purity of Materials: 293 1.53 Lutetium 2,5-dihydroxybenzoate was prepared by the same method as for ͑ cerium 2,5-dihydroxybenzoate using lutetium hydroxide or carbonate the Auxiliary Information ͕ ͑ ͒ ͖ ͒ formula of the complex: Lu C6H3 OH 2COO 3 . Method/Apparatus/Procedure: Estimated Errors: Isothermal method was used. After equilibrium had been established, Nothing speciﬁed. samples of 2 and 5 cm3 were withdrawn and the concentration of Pr͑III͒ ions was determined gravimetrically using the oxalate method.

Components: Original Measurements: Source and Purity of Materials: ͑1͒ Neodymium, 67W. Brzyska and A. Kula, J. Praseodymium 2,5-dihydroxybenzoate was prepared by the same method tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53, 161 as for cerium 2,5-dihydroxybenzoate using praseodymium hydroxide or ͑ ͕ ͑ ͒ ͖ ͒ ␬OЈ͒, ͑OC-6-11͒- ͑neodymium ͑1998͒. carbonate the formula of the complex: Pr C6H3 OH 2COO 3 . 2,5-dihydroxybenzoate͒; ͓ ͔ Estimated Errors: C21H15O12Nd; 217952-72-2 ͑ ͒ ͓ ͔ Nothing speciﬁed. 2 Water; H2O; 7732-18-5

Variables: Prepared by: T/K=293 H. Miyamoto

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Estimated Errors: Components: Original Measurements: Nothing speciﬁed. ͑1͒ Samarium, 67W. Brzyska and A. Kula, J. tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53, 161 ␬OЈ͒, ͑OC-6-11͒- ͑samarium ͑1998͒. 2,5-dihydroxybenzoate͒; Components: Original Measurements: ͓ ͔ ͑1͒ Thulium, 67W. Brzyska and A. Kula, J. C21H15O12Sm; 217952-73-3 ͑ ͒ ͓ ͔ tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53,161 2 Water; H2O; 7732-18-5 ␬OЈ͒, ͑OC-6-11͒- ͑thulium ͑1998͒. Variables: Prepared by: 2,5-dihydroxybenzoate͒; ͓ ͔ T/K=293 H. Miyamoto C21H15O12Tm; 217952-80-2 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Solubility of samarium 2,5-dihydroxybenzoate in water Variables: Prepared by: T/K=293 H. Miyamoto Temperature Solubility

/ 2 / −3 T K10c1 mol dm Solubility of thulium 2,5-dihydroxybenzoate in water

293 3.90 Temperature Solubility

/ 2 / −3 T K10c1 mol dm Auxiliary Information 293 3.72 Method/Apparatus/Procedure: Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Sm͑III͒ Auxiliary Information ions was determined gravimetrically using the oxalate method. Method/Apparatus/Procedure: Source and Purity of Materials: Isothermal method was used. After equilibrium had been established, Samarium 2,5-dihydroxybenzoate was prepared by the same method as for samples of 2 and 5 cm3 were withdrawn and the concentration of Tm͑III͒ cerium 2,5-dihydroxybenzoate using samarium hydroxide or carbonate ions was determined gravimetrically using the oxalate method. ͑ ͕ ͑ ͒ ͖ ͒ the formula of the complex: Sm C6H3 OH 2COO 3 . Source and Purity of Materials: Estimated Errors: Thulium 2,5-dihydroxybenzoate was prepared by the same method as for Nothing speciﬁed. cerium 2,5-dihydroxybenzoate using thulium hydroxide or carbonate ͑the ͕ ͑ ͒ ͖ ͒ formula of the complex: Tm C6H3 OH 2COO 3 .

Estimated Errors: Components: Original Measurements: Nothing speciﬁed. ͑1͒ Terbium, 67W. Brzyska and A. Kula, J. tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53, 161 ␬OЈ͒, ͑OC-6-11͒- ͑terbium ͑1998͒. 2,5-dihydroxybenzoate͒; Components: Original Measurements: ͓ ͔ ͑1͒ Ytterbium, 67W. Brzyska and A. Kula, J. C21H15O12Tb; 217952-76-6 ͑ ͒ ͓ ͔ tris͑2,5-dihydroxybenzoato-␬O, Therm. Anal. Calorim. 53,161 2 Water; H2O; 7732-18-5 ␬OЈ͒, ͑OC-6-11͒- ͑ytterbium ͑1998͒. Variables: Prepared by: 2,5-dihydroxybenzoate͒; ͓ ͔ T/K=293 H. Miyamoto C21H15O12Yb; 217952-81-3 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Solubility of terbium 2,5-dihydroxybenzoate in water Variables: Prepared by: T/K=293 H. Miyamoto Temperature Solubility

/ 2 / −3 T K10c1 mol dm Solubility of ytterbium 2,5-dihydroxybenzoate in water

293 3.91 Temperature Solubility

/ 2 / −3 T K10c1 mol dm Auxiliary Information 293 4.26 Method/Apparatus/Procedure: Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Tb͑III͒ ions was determined gravimetrically using the oxalate method.

Source and Purity of Materials: Terbium 2,5-dihydroxybenzoate was prepared by the same method as for cerium 2,5-dihydroxybenzoate using terbium hydroxide or carbonate ͑the ͕ ͑ ͒ ͖ ͒ formula of the complex: Tb C6H3 OH 2COO 3 .

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Auxiliary Information Solubility of dysprosium 2,6-dihydroxybenzoate in water

Method/Apparatus/Procedure: Temperature Solubilitya Isothermal method was used. After equilibrium had been established, 3 / 2 / −3 samples of 2 and 5 cm were withdrawn and the concentration of Tb͑III͒ T K10c1 mol dm ions was determined gravimetrically using the oxalate method. 293 1.54 Source and Purity of Materials: a Ytterbium 2,5-dihydroxybenzoate was prepared by the same method as for The compiler assumed from Ref. 67. cerium 2,5-dihydroxybenzoate using ytterbium hydroxide or carbonate ͑the ͕ ͑ ͒ ͖ ͒ Auxiliary Information formula of the complex: Yb C6H3 OH 2COO 3 .

Estimated Errors: Method/Apparatus/Procedure: Nothing speciﬁed Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Dy͑III͒ ions was determined gravimetrically using the oxalate method.

Components: Original Measurements: Source and Purity of Materials: ͑1͒ Yttrium, 67W. Brzyska and A. Kula, J. Dysprosium 2,6-dihydroxybenzoate was prepared by adding the equivalent tris͑2,5-dihydroxybenzoato- ␬O, Therm. Anal. Calorim. 53, 161 amounts of 0.2M ammonium 2,6-dihydroxybenzoate ͑pH 4.4–5.0͒ toahot ␬ Ј͒ ͑ ͒ ͑ ͑ ͒ O , OC-6-11 - yttrium 1998 . solution of DyCl3 and crystallization at room temperature as described in 2,5-dihydroxybenzoate͒; Ref. 67. ͓ ͔ C21H15O12Y; 217952-68-6 The compositions of the prepared complex were determined by elemental ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 analysis. The complex was prepared as a crystalline solid with a molar ratio of metal to organic ligand of 1:3 and formula Variables: Prepared by: ͓ ͕ ͑ ͒ ͖ ͔ Dy C6H3 OH 2COO 3 ·6H2O. T/K=293 H. Miyamoto Estimated Errors: Nothing speciﬁed. Solubility of yttrium 2,5-dihydroxybenzoate in water

Temperature Solubility Components: Original Measurements: / 2 / −3 68 T K10c1 mol dm ͑1͒ Erbium W. Brzyska, A. Kula, Z. 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, 293 3.19 ͑ ͒ hexahydrate; C21H15O12Er·6H2O; Polish J. Chem. 72,2524 1998 . ͓͔ ͑ ͒ ͓ ͔ Auxiliary Information 2 Water; H2O; 7732-18-5

Method/Apparatus/Procedure: Variables: Prepared by: / Isothermal method was used. After equilibrium had been established, T K=293 H. Miyamoto samples of 2 and 5 cm3 were withdrawn and the concentration of Y͑III͒ ions was determined gravimetrically using the oxalate method. Solubility of erbium 2,6-dihydroxybenzoate in water Source and Purity of Materials: Temperature Solubilitya Yttrium 2,5-dihydroxybenzoate was prepared by the same method as for ͑ cerium 2,5-diydroxybenzoate using yttrium hydroxide or carbonate the T/K102c /mol dm−3 ͕ ͑ ͒ ͖ ͒ 1 formula of the complex: Y C6H3 OH 2COO 3 . 293 1.61 Estimated Errors: Nothing speciﬁed. aThe compiler assumed from Ref. 67.

Auxiliary Information

Method/Apparatus/Procedure: Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Er͑III͒ 2.3.2.4. 2,6-Dihydroxybenzoic acid salts ions was determined gravimetrically using the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Erbium 2,6-dihydroxybenzoate was prepared by the same method as for ͑ ͒ 68 ͑ 1 Dysprosium W. Brzyska, A. Kula, Z. dysprosium 2,6-dihydroxybenzoate using ErCl3 the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, complex: Er C6H3 OH 2COO 3 ·6H2O . hexahydrate; Polish J. Chem. 72, 2524 ͑1998͒. ͓͔ C21H15O12Dy·6H2O; Estimated Errors: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Nothing speciﬁed.

Variables: Prepared by: T/K=293 H. Miyamoto

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Source and Purity of Materials: Components: Original Measurements: Holmium 2,6-dihydroxybenzoate was prepared by the same method as for ͑1͒ Gadolinium 68W. Brzyska, A. Kula, Z. ͑ dysprosium 2,6-dihydroxybenzoate using HoCl3 the formula of the 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Ho C6H3 OH 2COO 3 ·6H2O . hexahydrate; Polish J. Chem. 72, 2524 ͑1998͒. ͓͔ C21H15O12Gd·6H2O; Estimated Errors: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Nothing speciﬁed.

Variables: Prepared by: T/K=293 H. Miyamoto Components: Original Measurements: ͑1͒ Lutetium 68W. Brzyska, A. Kula, Z. Solubility of gadolinium 2,6-dihydroxybenzoate in water 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, hexahydrate; Polish J. Chem. 72,2524͑1998͒. a ͓͔ Temperature Solubility C21H15O12Lu·6H2O; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 2 / −3 T K10c1 mol dm Variables: Prepared by: 293 1.98 T/K=293 H. Miyamoto

aThe compiler assumed from Ref. 67. Solubility of lutetium 2,6-dihydroxybenzoate in water Auxiliary Information Temperature Solubilitya Method/Apparatus/Procedure / 2 / −3 Isothermal method was used. After equilibrium had been established, T K10c1 mol dm samples of 2 and 5 cm3 were withdrawn and the concentration of Gd͑III͒ ions was determined gravimetrically using the oxalate method. 293 1.20

Source and Purity of Materials: aThe compiler assumed from Ref. 67. Gadolinium 2,6-dihydroxybenzoate was prepared by the same method as ͑ Auxiliary Information for dysprosium 2,6-dihydroxybenzoate using GdCl3 the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Gd C6H3 OH 2COO 3 ·6H2O . Method/Apparatus/Procedure: Estimated Errors: Isothermal method was used. After equilibrium had been established, Nothing speciﬁed. samples of 2 and 5 cm3 were withdrawn and the concentration of Lu͑III͒ ions was determined gravimetrically using the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Lutetium 2,6-dihydroxybenzoate was prepared by the same method as for ͑1͒ Holmium 68W. Brzyska, A. Kula, Z. ͑ dysprosium 2,6-dihydroxybenzoate using LuCl3 the formula of the 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Lu C6H3 OH 2COO 3 ·6H2O . hexahydrate; Polish J. Chem. 72, 2524 ͑1998͒. ͓͔ C21H15O12Ho·6H2O; Estimated Errors: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Nothing speciﬁed.

Variables: Prepared by: T/K=293 H. Miyamoto Components: Original Measurements: ͑1͒ Terbium 68W. Brzyska, A. Kula, Z. Solubility of holmium 2,6-dihydroxybenzoate in water 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, hexahydrate; Polish J. Chem. 72,2524͑1998͒. a ͓͔ Temperature Solubility C21H15O12Tb·6H2O; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 2 / −3 T K10c1 mol dm Variables: Prepared by: 293 1.21 T/K=293 H. Miyamoto

aThe compiler assumed from Ref. 67. Solubility of terbium 2,6-dihydroxybenzoate in water Auxiliary Information Temperature Solubilitya Method/Apparatus/Procedure: / 2 / −3 Isothermal method was used. After equilibrium had been established, T K10c1 mol dm samples of 2 and 5 cm3 were withdrawn and the concentration of Ho͑III͒ ions was determined gravimetrically using the oxalate method. 293 1.89

aThe compiler assumed from Ref. 67.

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Auxiliary Information Solubility of ytterbium 2,6-dihydroxybenzoate in water

Method/Apparatus/Procedure: Temperature Solubilitya Isothermal method was used. After equilibrium had been established, 3 / 2 / −3 samples of 2 and 5 cm were withdrawn and the concentration of Tb͑III͒ T K10c1 mol dm ions was determined gravimetrically using the oxalate method. 293 1.39 Source and Purity of Materials: a Terbium 2,6-dihydroxybenzoate was prepared by the same method as for The compiler assumed from Ref. 67. ͑ dysprosium 2,6-dihydroxybenzoate using TbCl3 the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ Auxiliary Information complex: Tb C6H3 OH 2COO 3 ·6H2O .

Estimated Errors: Method/Apparatus/Procedure: Nothing speciﬁed. Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Yb͑III͒ ions was determined gravimetrically using the oxalate method.

Components: Original Measurements: Source and Purity of Materials: ͑1͒ Thulium 68W. Brzyska, A. Kula, Z. Ytterbium 2,6-dihydroxybenzoate was prepared by the same method as for ͑ 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, dysprosium 2,6-dihydroxybenzoate using YbCl3 the formula of the ͑ ͒ ͕ ͑ ͒ ͖ ͒ hexahydrate; Polish J. Chem. 72, 2524 1998 . complex: Yb C6H3 OH 2COO 3 ·6H2O . ͓͔ C21H15O12Tm·6H2O; ͑ ͒ ͓ ͔ Estimated Errors: 2 Water; H2O; 7732-18-5 Nothing speciﬁed. Variables: Prepared by: T/K=293 H. Miyamoto Components: Original Measurements: Solubility of thulium 2,6-dihydroxybenzoate in water ͑1͒ Yttrium 68W. Brzyska, A. Kula, Z. 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, a ͑ ͒ Temperature Solubility hexahydrate; C21H15O12Y·6H2O; Polish J. Chem. 72,2524 1998 . ͓͔ / 2 / −3 ͑ ͒ ͓ ͔ T K10c1 mol dm 2 Water; H2O; 7732-18-5

293 1.48 Variables: Prepared by: T/K=293 H. Miyamoto aThe compiler assumed from Ref. 67.

Auxiliary Information Solubility of yttrium 2,6-dihydroxybenzoate in water

Method/Apparatus/Procedure: Temperature Solubilitya Isothermal method was used. After equilibrium had been established, 3 / 2 / −3 samples of 2 and 5 cm were withdrawn and the concentration of Tm͑III͒ T K10c1 mol dm ions was determined gravimetrically using the oxalate method. 293 1.91 Source and Purity of Materials: a Thulium 2,6-dihydroxybenzoate was prepared by the same method as for The compiler assumed from Ref. 67. ͑ dysprosium 2,6-dihydroxybenzoate using TmCl3 the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ Auxiliary Information complex: Tm C6H3 OH 2COO 3 ·6H2O .

Estimated Errors: Method/Apparatus/Procedure: Nothing speciﬁed. Isothermal method was used. After equilibrium had been established, samples of 2 and 5 cm3 were withdrawn and the concentration of Y͑III͒ ions was determined gravimetrically using the oxalate method.

Components: Original Measurements: Source and Purity of Materials: ͑1͒ Ytterbium, 68W. Brzyska, A. Kula, Z. Yttrium 2,6-dihydroxybenzoate was prepared by the same method as for ͑ 2,6-dihydroxybenzoate Rzaczynska, and J. Jaroniec, dysprosium 2,6-dihydroxybenzoate using YCl3 the formula of the ͑ ͒ ͓ ͕ ͑ ͒ ͖ ͔ ͒ hexahydrate; Polish J. Chem. 72, 2524 1998 . complex: Y C6H3 OH 2COO 3 ·6H2O . ͓͔ C21H15O12Yb·6H2O; ͑ ͒ ͓ ͔ Estimated Errors: 2 Water; H2O; 7732-18-5 Nothing speciﬁed. Variables: Prepared by: T/K=293 H. Miyamoto

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2.3.2.5. 3,4-Dihydroxybenzoic acid salts Auxiliary Information

Methods/Apparatus/Procedure: Components: Original Measurements: The solubility of dysprosium 3,4-dihydroxybenzoate in water was ͑1͒ Cerium 69W. Brzyska and A. Kula, determined at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and tris͑3,4-dihydroxybenzoato- O1, Thermochim. Acta 239, 127 the concentration of Dy͑III͒ ions was determined spectrophotometrically O1Ј͒ trihydrate, ͑OC-6-11͒- ͑1994͒. using arsenazo III. ͑cerium 3,4-dihydroxybenzoate ͒ Source and Purity of Materials: trihydrate ;C21H15CeO12 ·3H2O; ͓158477-56-6͔ Dysprosium 3,4-dihydroxybenzoate was prepared by the same method as ͑ ͒ ͓ ͔ ͑ 2 Water; H2O; 7732-18-5 for cerium 3,4-dihydroxybenzoate using dysprosium chloride the formula ͓ ͕ ͑ ͒ ͖ ͔ ͒ of the complex: Dy C6H3 OH 2COO 3 ·2H2O . Variables: Prepared by: T/K=293 H. Miyamoto Estimated Errors: Nothing speciﬁed.

Solubility of cerium 3,4-dihydroxybenzoate in water

Components: Original Measurements: Temperature Solubility ͑1͒ Erbium, 69W. Brzyska and A. Kula, / 4 / −3 ͑ 1 T K10c1 mol dm tris 3,4-dihydroxybenzoato-O , Thermochim. Acta 239,127 O1Ј͒ trihydrate, ͑OC-6-11͒- ͑1994͒. 293 9.47 ͑erbium 3,4-dihydroxybenzoate ͒ trihydrate ;C21H15ErO12 ·3H2O; ͓158477-60-2͔ Auxiliary Information ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Methods/Apparatus/Procedure: Variables: Prepared by: The solubility of cerium 3,4-dihydroxybenzoate in water was determined T/K=293 H. Miyamoto at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the concentration of Ce͑III͒ ions was determined spectrophotometrically using arsenazo III. Solubility of erbium 3,4-dihydroxybenzoate in water

Source and Purity of Materials: Temperature Solubility Cerium 3,4-dihydroxybenzoate was prepared by addition of an equivalent ͑ ͒ / 4 / −3 quantity of ammonium 3,4-dihydroxybenzoate pH 4.4–4.5 to a solution T K10c1 mol dm of cerium chloride at room temperature. The precipitate formed was filtered, washed with ethanol, and dried at 303 K to a constant mass. The 293 8.61 quantitative compositions of the prepared complex were determined by elemental analysis. The water content of crystallization was determined Auxiliary Information from the TG curve and by isothermal heating of the complex at specified temperatures. The complex was obtained as a solid with a molar ratio of Methods/Apparatus/Procedure: metal to organic ligand of 1:3 and formula ͓Ce͕C H ͑OH͒ COO͖ ͔·3H O. 6 3 2 3 2 The solubility of erbium 3,4-dihydroxybenzoate in water was determined 3 Estimated Errors: at 293 K. Samples of 1, 2, 5, and 10 cm were removed and the concentration of Er͑III͒ ions was determined spectrophotometrically using Nothing specified. arsenazo III.

Source and Purity of Materials: Components: Original Measurements: Erbium 3,4-dihydroxybenzoate was prepared by the same method as for ͑1͒ Dysprosium, 69W. Brzyska and A. Kula, cerium 3,4-dihydroxybenzoate using erbium chloride ͑the formula of the 1 ͓ ͕ ͑ ͒ ͖ ͔ ͒ tris͑3,4-dihydroxybenzoato-O , Thermochim. Acta 239, 127 complex: Er C6H3 OH 2COO 3 ·3H2O . O1Ј͒ dihydrate, ͑OC-6-11͒- ͑1994͒. ͑dysprosium Estimated Errors: 3,4-dihydroxybenzoate Nothing speciﬁed. ͒ dihydrate ;C21H15DyO12 ·2H2O; ͓158477-53-3͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: ͑1͒ Europium, 69W. Brzyska and A. Kula, Variables: Prepared by: tris͑3,4-dihydroxybenzoato-O1, Thermochim. Acta 239,127 T/K=293 H. Miyamoto O1Ј͒ dihydrate, ͑OC-6-11͒- ͑1994͒. ͑europium 3,4-dihydroxybenzoate ͒ Solubility of dysprosium 3,4-dihydroxybenzoate in water dihydrate ;C21H15EuO12 ·2H2O; ͓158477-50-0͔ ͑ ͒ ͓ ͔ Temperature Solubility 2 Water; H2O; 7732-18-5

/ 4 / −3 Variables: Prepared by: T K10c1 mol dm T/K=293 H. Miyamoto 293 5.81

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Solubility of europium 3,4-dihydroxybenzoate in water Components: Original Measurements: 69 Temperature Solubility ͑1͒ Holmium, W. Brzyska and A. Kula, tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239,127 / 4 / −3 ͑ ͒ ͑ ͑ ͒ T K10c1 mol dm trihydrate, OC-6-11 - holmium 1994 . 3,4-dihydroxybenzoate 293 5.31 ͒ trihydrate ;C21H15HoO12 ·3H2O; ͓158477-59-9͔ ͑2͒ Water; H O; ͓7732-18-5͔ Auxiliary Information 2 Variables: Prepared by: Methods/Apparatus/Procedure: T/K=293 H. Miyamoto The solubility of europium 3,4-dihydroxybenzoate in water was determined at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the concentration of Eu͑III͒ ions was determined spectrophotometrically Solubility of holmium 3,4-dihydroxybenzoate in water using arsenazo III. Temperature Solubility Source and Purity of Materials: / 4 / −3 Europium 3,4-dihydroxybenzoate was prepared by the same method as for T K10c1 mol dm cerium 3,4-dihydroxybenzoate using europium chloride ͑the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Eu C6H3 OH 2COO 3 ·2H2O . 293 7.36

Estimated Errors: Nothing speciﬁed. Auxiliary Information Methods/Apparatus/Procedure: The solubility of holmium 3,4-dihydroxybenzoate in water was determined Components: Original Measurements: at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the ͑1͒ Gadolinium, 69W. Brzyska and A. Kula, concentration of Ho͑III͒ ions was determined spectrophotometrically using tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239, 127 arsenazo III. dihydrate, ͑OC-6-11͒- ͑1994͒. ͑gadolinium Source and Purity of Materials: 3,4-dihydroxybenzoate Holmium 3,4-dihydroxybenzoate was prepared by the same method as for ͒ ͑ dihydrate ;C21H15GdO12 ·2H2O; cerium 3,4-dihydroxybenzoate using holmium chloride the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ ͓158477-51-1͔ complex: Ho C6H3 OH 2COO 3 ·3H2O . ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Estimated Errors: Variables: Prepared by: Nothing speciﬁed. T/K=293 H. Miyamoto

Solubility of gadolinium 3,4-dihydroxybenzoate in water Components: Original Measurements: ͑1͒ Lanthanum, 69W. Brzyska and A. Kula, ͑ 1 1 ͒ Temperature Solubility tris 3,4-dihydroxybenzoato-O ,O Ј Thermochim. Acta 239,127 trihydrate, ͑OC-6-11͒- ͑1994͒. / 4 / −3 ͑ T K10c1 mol dm lanthanum 3,4-dihydroxybenzoate 293 1.99 ͒ trihydrate ;C21H15LaO12 ·3H2O; ͓158477-55-5͔ ͑2͒ Water; H O; ͓7732-18-5͔ Auxiliary Information 2 Variables: Prepared by: Methods/Apparatus/Procedure: T/K=293 H. Miyamoto The solubility of gadolinium 3,4-dihydroxybenzoate in water was determined at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the concentration of Gd͑III͒ ions was determined spectrophotometrically Solubility of lanthanum 3,4-dihydroxybenzoate in water using arsenazo III. Temperature Solubility Source and Purity of Materials: / 4 / −3 Gadolinium 3,4-dihydroxybenzoate was prepared by the same method as T K10c1 mol dm for cerium 3,4-dihydroxybenzoate using gadolinium chloride ͑the formula ͓ ͕ ͑ ͒ ͖ ͔ ͒ of the complex: Gd C6H3 OH 2COO 3 ·2H2O . 293 19.81

Estimated Errors: Nothing speciﬁed. Auxiliary Information Methods/Apparatus/Procedure: The solubility of lanthanum 3,4-dihydroxybenzoate in water was determined at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the concentration of La͑III͒ ions was determined spectrophotometrically using arsenazo III.

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Source and Purity of Materials: Auxiliary Information Lanthanum 3,4-dihydroxybenzoate was prepared by the same method as for cerium 3,4-dihydroxybenzoate using lanthanum chloride ͑the formula Methods/Apparatus/Procedure: ͓ ͕ ͑ ͒ ͖ ͔ ͒ of the complex: La C6H3 OH 2COO 3 ·3H2O . The solubility of neodymium 3,4-dihydroxybenzoate in water was determined at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and Estimated Errors: the concentration of Nd͑III͒ ions was determined spectrophotometrically Nothing speciﬁed. using arsenazo III.

Source and Purity of Materials: Neodymium 3,4-dihydroxybenzoate was prepared by the same method as Components: Original Measurements: ͑ 69 for cerium 3,4-dihydroxybenzoate using neodymium chloride the formula ͑1͒ Lutetium, W. Brzyska and A. Kula, ͓ ͕ ͑ ͒ ͖ ͔ ͒ of the complex: Nd C6H3 OH 2COO 3 ·3H2O . tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239, 127 dihydrate, ͑OC-6-11͒- ͑lutetium ͑1994͒. Estimated Errors: 3,4-dihydroxybenzoate Nothing speciﬁed. ͒ dihydrate ;C21H15LuO12 ·2H2O; ͓158477-54-4͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: Variables: Prepared by: ͑1͒ Praseodymium, 69W. Brzyska and A. Kula, T/K=293 H. Miyamoto tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239,127 trihydrate, ͑OC-6-11͒- ͑1994͒. ͑praseodymium Solubility of lutetium 3,4-dihydroxybenzoate in water 3,4-dihydroxybenzoate ͒ trihydrate ;C21H15O12Pr·3H2O; Temperature Solubility ͓158477-57-7͔ ͑2͒ Water; H O; ͓7732-18-5͔ / 4 / −3 2 T K10c1 mol dm Variables: Prepared by: 293 0.84 T/K=293 H. Miyamoto

Auxiliary Information Solubility of praseodymium 3,4-dihydroxybenzoate in water Methods/Apparatus/Procedure: The solubility of lutetium 3,4-dihydroxybenzoate in water was determined Temperature Solubility at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the T/K104c /mol dm−3 concentration of Lu͑III͒ ions was determined spectrophotometrically using 1 arsenazo III. 293 18.65 Source and Purity of Materials: Lutetium 3,4-dihydroxybenzoate was prepared by the same method as for Auxiliary Information cerium 3,4-dihydroxybenzoate using lutetium chloride ͑the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Lu C6H3 OH 2COO 3 ·2H2O . Methods/Apparatus/Procedure: The solubility of praseodymium 3,4-dihydroxybenzoate in water was Estimated Errors: determined at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and Nothing speciﬁed. the concentration of Pr͑III͒ ions was determined spectrophotometrically using arsenazo III.

Source and Purity of Materials: Components: Original Measurements: 69 Praseodymium 3,4-dihydroxybenzoate was prepared by the same method ͑1͒ Neodymium, W. Brzyska and A. Kula, as for cerium 3,4-dihydroxybenzoate using praseodymium chloride ͑the tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239, 127 formula of the complex: ͓Pr͕C H ͑OH͒ COO͖ ͔·3H O͒. trihydrate, ͑OC-6-11͒- ͑1994͒. 6 3 2 3 2 ͑ neodymium Estimated Errors: 3,4-dihydroxybenzoate ͒ Nothing speciﬁed. trihydrate ;C21H15NdO12 ·3H2O; ͓158477-58-8͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: T/K=293 H. Miyamoto

Solubility of neodymium 3,4-dihydroxybenzoate in water

Temperature Solubility

/ 4 / −3 T K10c1 mol dm

293 38.29

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Source and Purity of Materials: Components: Original Measurements: Terbium 3,4-dihydroxybenzoate was prepared by the same method as for 69 ͑1͒ Samarium, W. Brzyska and A. Kula, cerium 3,4-dihydroxybenzoate using terbium chloride ͑the formula of the tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239, 127 ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Tb C6H3 OH 2COO 3 ·2H2O . dihydrate, ͑OC-6-11͒- ͑samarium ͑1994͒. 3,4-dihydroxybenzoate Estimated Errors: ͒ dihydrate ;C21H15O12Sm·2H2O; Nothing speciﬁed. ͓158477-49-7͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: Variables: Prepared by: ͑1͒ Thulium, 69W. Brzyska and A. Kula, T/K=293 H. Miyamoto tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239,127 trihydrate, ͑OC-6-11͒- ͑thulium ͑1994͒. Solubility of samarium 3,4-dihydroxybenzoate in water 3,4-dihydroxybenzoate ͒ trihydrate ;C21H15O12Tm·3H2O; Temperature Solubility ͓158477-61-3͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 4 / −3 T K10c1 mol dm Variables: Prepared by: 293 0.74 T/K=293 H. Miyamoto

Auxiliary Information Solubility of thulium 3,4-dihydroxybenzoate in water

Methods/Apparatus/Procedure: Temperature Solubility The solubility of samarium 3,4-dihydroxybenzoate in water was 3 / 4 / −3 determined at 293 K. Samples of 1, 2, 5, and 10 cm were removed and T K10c1 mol dm the concentration of Sm͑III͒ ions was determined spectrophotometrically using arsenazo III. 293 9.28

Source and Purity of Materials: Auxiliary Information Samarium 3,4-dihydroxybenzoate was prepared by the same method as for cerium 3,4-dihydroxybenzoate using samarium chloride ͑the formula of Methods/Apparatus/Procedure: ͓ ͕ ͑ ͒ ͖ ͔ ͒ the complex: Sm C6H3 OH 2COO 3 ·2H2O . The solubility of thulium 3,4-dihydroxybenzoate in water was determined at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the Estimated Errors: concentration of Tm͑III͒ ions was determined spectrophotometrically using Nothing speciﬁed. arsenazo III.

Source and Purity of Materials: Components: Original Measurements: Thulium 3,4-dihydroxybenzoate was prepared by the same method as for ͑ ͑1͒ Terbium, 69W. Brzyska and A. Kula, cerium 3,4-dihydroxybenzoate using thulium chloride the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239, 127 complex: Tm C6H3 OH 2COO 3 ·3H2O . dihydrate, ͑OC-6-11͒- ͑terbium ͑1994͒. Estimated Errors: 3,4-dihydroxybenzoate ͒ Nothing speciﬁed. dihydrate ;C21H15O12Tb·2H2O; ͓158477-52-2͔ ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Components: Original Measurements: Variables: Prepared by: ͑1͒ Ytterbium, 69W. Brzyska and A. Kula, T/K=293 H. Miyamoto tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239,127 trihydrate, ͑OC-6-11͒- ͑ytterbium ͑1994͒. 3,4-dihydroxybenzoate Solubility of terbium 3,4-dihydroxybenzoate in water ͒ trihydrate ;C21H15O12Yb·3H2O; ͓158477-62-4͔ Temperature Solubility ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 4 / −3 T K10c1 mol dm Variables: Prepared by: T/K=293 H. Miyamoto 293 1.75

Solubility of ytterbium 3,4-dihydroxybenzoate in water Auxiliary Information Temperature Solubility Methods/Apparatus/Procedure: The solubility of terbium 3,4-dihydroxybenzoate in water was determined / 4 / −3 T K10c1 mol dm at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the concentration of Tb͑III͒ ions was determined spectrophotometrically using 293 4.89 arsenazo III.

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Auxiliary Information Solubility of cerium 3,5-dihydroxybenzoate in water

Methods/Apparatus/Procedure: Temperature Solubility The solubility of ytterbium 3,4-dihydroxybenzoate in water was 3 / 2 / −3 determined at 293 K. Samples of 1, 2, 5, and 10 cm were removed and T K10c1 mol dm the concentration of Yb͑III͒ ions was determined spectrophotometrically using arsenazo III. 293 11.27

Source and Purity of Materials: Auxiliary Information Ytterbium 3,4-dihydroxybenzoate was prepared by the same method as for ͑ cerium 3,4-dihydroxybenzoate using ytterbium chloride the formula of Methods/Apparatus/Procedure: ͓ ͕ ͑ ͒ ͖ ͔ ͒ the complex: Yb C6H3 OH 2COO 3 ·3H2O . The solubility of cerium 3,5-dihydroxybenzoate in water was determined at 293 K. Saturated solutions were prepared under isothermal condition. Estimated Errors: After equilibrium had been established, samples of 1, 2, and 5 cm3 were Nothing speciﬁed. removed and the concentration of Ce͑III͒ ions was determined gravimetrically using the oxalate method.

Components: Original Measurements: Source and Purity of Materials: ͑1͒ Yttrium, 69W. Brzyska and A. Kula, Cerium 3,5-dihydroxybenzoate was freshly prepared from cerium͑III͒ tris͑3,4-dihydroxybenzoato-O1 ,O1Ј͒ Thermochim. Acta 239, 127 carbonate in a solution of 3,5-hydroxybenzoic acid at room temperature, dihydrate, ͑OC-6-11͒- ͑yttrium ͑1994͒. followed by crystallization. The precipitates formed were ﬁltered, washed 3,4-dihydroxybenzoate with water, and dried at 303 K to a constant mass. The quantitative ͒ dihydrate ;C21H15O12Y·2H2O; compositions of the prepared 3,5-hydroxybenzoate were determined by ͓158477-48-6͔ elemental analysis. The water content of crystallization was determined ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 from the TG curve and by isothermal heating of the complex at a speciﬁed temperature. The complex was prepared as a solid with a molar Variables: Prepared by: ratio of metal to organic ligand of 1:3 and formula / ͓ ͕ ͑ ͒ ͖ ͔ T K=293 H. Miyamoto Ce C6H3 OH 2COO 3 ·4H2O.

Estimated Errors: Solubility of yttrium 3,4-dihydroxybenzoate in water Nothing speciﬁed.

Temperature Solubility

/ 4 / −3 T K10c1 mol dm Components: Original Measurements: ͑1͒ Dysprosium 70W. Brzyska and A. Kula, 293 3.41 3,5-dihydroxybenzoate Thermochim. Acta 277,29 heptahydrate; ͑1996͒. ͓͔ Auxiliary Information C21H15O12Dy·7H2O; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Methods/Apparatus/Procedure: Variables: Prepared by: The solubility of yttrium 3,4-dihydroxybenzoate in water was determined / at 293 K. Samples of 1, 2, 5, and 10 cm3 were removed and the T K=293 H. Miyamoto concentration of Y͑III͒ ions was determined spectrophotometrically using arsenazo III. Solubility of dysprosium 3,5-dihydroxybenzoate in water Source and Purity of Materials: Temperature Solubility Yttrium 3,4-dihydroxybenzoate was prepared by the same method as for cerium 3,4-dihydroxybenzoate using yttrium chloride ͑the formula of the T/K102c /mol dm−3 ͓ ͕ ͑ ͒ ͖ ͔ ͒ 1 complex: Y C6H3 OH 2COO 3 ·2H2O . 293 6.64 Estimated Errors: Nothing speciﬁed. Auxiliary Information

Methods/Apparatus/Procedure: The solubility of dysprosium 3,5-dihydroxybenzoate in water was 2.3.2.6. 3,5-Dihydroxybenzoic acid salts determined at 293 K. Saturated solutions were prepared under isothermal condition. After equilibrium had been established, samples of 1, 2, and 5cm3 were removed and the concentration of Dy͑III͒ ions was determined Components: Original Measurements: gravimetrically using the oxalate method. ͑1͒ Cerium 70W. Brzyska and A. Kula, 3,5-dihydroxybenzoate Thermochim. Acta 277,29 Source and Purity of Materials: ͑ ͒ tetrahydrate; C21H15O12Ce·4H2O; 1996 . Dysprosium 3,5-dihydroxybenzoate was prepared by the same method as ͓͔ for cerium 3,5-dihydroxybenzoate using dysprosium chloride ͑the formula ͑ ͒ ͓ ͔ ͓ ͕ ͑ ͒ ͖ ͔ ͒ 2 Water; H2O; 7732-18-5 of the complex: Dy C6H3 OH 2COO 3 ·7H2O .

Variables: Prepared by: Estimated Errors: T/K=293 H. Miyamoto Nothing speciﬁed.

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Auxiliary Information Components: Original Measurements: ͑1͒ Erbium 70W. Brzyska and A. Kula, Methods/Apparatus/Procedure: 3,5-dihydroxybenzoate Thermochim. Acta 277,29 The solubility of europium 3,5-dihydroxybenzoate in water was heptahydrate; ͑1996͒. determined at 293 K. Saturated solutions were prepared under isothermal ͓͔ C21H15O12Er·7H2O; condition. After equilibrium had been established, samples of 1, 2, and ͑ ͒ ͓ ͔ 3 2 Water; H2O; 7732-18-5 5cm were removed and the concentration of Eu͑III͒ ions was determined gravimetrically using the oxalate method. Variables: Prepared by: T/K=293 H. Miyamoto Source and Purity of Materials: Europium 3,5-dihydroxybenzoate was prepared by the same method as for cerium 3,5-dihydroxybenzoate using europium chloride ͑the formula of the Solubility of erbium 3,5-dihydroxybenzoate in water ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Eu C6H3 OH 2COO 3 ·7H2O .

Temperature Solubility Estimated Errors: Nothing speciﬁed. / 2 / −3 T K10c1 mol dm

293 7.68 Components: Original Measurements: ͑1͒ Gadolinium 70W. Brzyska and A. Kula, Auxiliary Information 3,5-dihydroxybenzoate Thermochim. Acta 277,29 ͑ ͒ Methods/Apparatus/Procedure: heptahydrate; 1996 . C H O Gd·7H O; ͓͔ The solubility of erbium 3,5-dihydroxybenzoate in water was determined 21 15 12 2 ͑2͒ Water; H O; ͓7732-18-5͔ at 293 K. Saturated solutions were prepared under isothermal condition. 2 3 After equilibrium had been established, samples of 1, 2, and 5 cm were Variables: Prepared by: removed and the concentration of Er͑III͒ ions was determined T/K=293 H. Miyamoto gravimetrically using the oxalate method.

Source and Purity of Materials: Solubility of gadolinium 3,5-dihydroxybenzoate in water Erbium 3,5-dihydroxybenzoate was prepared by the same method as for ͑ cerium 3,5-dihydroxybenzoate using erbium chloride the formula of the Temperature Solubility ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Er C6H3 OH 2COO 3 ·7H2O . / 2 / −3 T K10c1 mol dm Estimated Errors: Nothing speciﬁed. 293 7.83

Auxiliary Information Components: Original Measurements: ͑1͒ Europium 70W. Brzyska and A. Kula, Methods/Apparatus/Procedure: 3,5-dihydroxybenzoate Thermochim. Acta 277,29 The solubility of gadolinium 3,5-dihydroxybenzoate in water was heptahydrate; ͑1996͒. determined at 293 K. Saturated solutions were prepared under isothermal ͓͔ C21H15O12Eu·7H2O; condition. After equilibrium had been established, samples of 1, 2, and ͑ ͒ ͓ ͔ 3 2 Water; H2O; 7732-18-5 5cm were removed and the concentration of Gd͑III͒ ions was determined gravimetrically using the oxalate method. Variables: Prepared by: T/K=293 H. Miyamoto Source and Purity of Materials: Gadolinium 3,5-dihydroxybenzoate was prepared by the same method as for cerium 3,5-dihydroxybenzoate using gadolinium chloride ͑the formula Solubility of europium 3,5-dihydroxybenzoate in water ͓ ͕ ͑ ͒ ͖ ͔ ͒ of the complex: Gd C6H3 OH 2COO 3 ·7H2O .

Temperature Solubility Estimated Errors: Nothing speciﬁed. / 2 / −3 T K10c1 mol dm

293 9.54 Components: Original Measurements: ͑1͒ Holmium 70W. Brzyska and A. Kula, 3,5-dihydroxybenzoate Thermochim. Acta 277,29 heptahydrate; ͑1996͒. ͓͔ C21H15O12Ho·7H2O; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: T/K=293 H. Miyamoto

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Solubility of holmium 3,5-dihydroxybenzoate in water Components: Original Measurements: 70 Temperature Solubility ͑1͒ Lanthanum W. Brzyska and A. Kula, 3,5-dihydroxybenzoate Thermochim. Acta 277,29 / 2 / −3 ͑ ͒ T K10c1 mol dm tetrahydrate; C21H15O12La·4H2O; 1996 . ͓͔ 293 6.24 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Auxiliary Information T/K=293 H. Miyamoto Methods/Apparatus/Procedure: The solubility of holmium 3,5-dihydroxybenzoate in water was determined Solubility of lanthanum 3,5-dihydroxybenzoate in water at 293 K. Saturated solutions were prepared under isothermal condition. 3 After equilibrium had been established, samples of 1, 2, and 5 cm were Temperature Solubility removed and the concentration of Ho͑III͒ ions was determined / 2 / −3 gravimetrically using the oxalate method. T K10c1 mol dm

Source and Purity of Materials: 293 10.80 Holmium 3,5-dihydroxybenzoate was prepared by the same method as for cerium 3,5-dihydroxybenzoate using holmium chloride ͑the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ Auxiliary Information complex: Ho C6H3 OH 2COO 3 ·7H2O .

Estimated Errors: Methods/Apparatus/Procedure: Nothing speciﬁed. The solubility of lanthanum 3,5-dihydroxybenzoate in water was determined at 293 K. Saturated solutions were prepared under isothermal condition. After equilibrium had been established, samples of 1, 2, and 5cm3 were removed and the concentration of La͑III͒ ions was determined Components: Original Measurements: gravimetrically using the oxalate method. ͑1͒ Neodymium 70W. Brzyska and A. Kula, 3,5-dihydroxybenzoate Thermochim. Acta 277,29 Source and Purity of Materials: heptahydrate; ͑1996͒. Lanthanum 3,5-dihydroxybenzoate was prepared by the same method as ͓͔ ͑ C21H15O12Nd·7H2O; for cerium 3,5-dihydroxybenzoate using lanthanum chloride the formula ͑ ͒ ͓ ͔ ͓ ͕ ͑ ͒ ͖ ͔ ͒ 2 Water; H2O; 7732-18-5 of the complex: La C6H3 OH 2COO 3 ·4H2O .

Variables: Prepared by: Estimated Errors: T/K=293 H. Miyamoto Nothing speciﬁed.

Solubility of neodymium 3,5-dihydroxybenzoate in water Components: Original Measurements: 70 Temperature Solubility ͑1͒ Lutetium W. Brzyska and A. Kula, 3,5-dihydroxybenzoate Thermochim. Acta 277,29 / 2 / −3 ͑ ͒ T K10c1 mol dm heptahydrate; 1996 . ͓͔ C21H15O12Lu·7H2O; 293 25.14 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Auxiliary Information T/K=293 H. Miyamoto Methods/Apparatus/Procedure: The solubility of neodymium 3,5-dihydroxybenzoate in water was Solubility of lutetium 3,5-dihydroxybenzoate in water determined at 293 K. Saturated solutions were prepared under isothermal condition. After equilibrium had been established, samples of 1, 2, and Temperature Solubility 5cm3 were removed and the concentration of Nd͑III͒ ions was determined / 2 / −3 gravimetrically using the oxalate method. T K10c1 mol dm

Source and Purity of Materials: 293 11.30 Neodymium 3,5-dihydroxybenzoate was prepared by the same method as for cerium 3,5-dihydroxybenzoate using neodymium chloride ͑the formula ͓ ͕ ͑ ͒ ͖ ͔ ͒ Auxiliary Information of the complex: Nd C6H3 OH 2COO 3 ·7H2O .

Estimated Errors: Methods/Apparatus/Procedure: Nothing speciﬁed. The solubility of lutetium 3,5-dihydroxybenzoate in water was determined at 293 K. Saturated solutions were prepared under isothermal condition. After equilibrium had been established, samples of 1, 2, and 5 cm3 were removed and the concentration of Lu͑III͒ ions was determined gravimetrically using the oxalate method.

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Source and Purity of Materials: Auxiliary Information Lutetium 3,5-dihydroxybenzoate was prepared by the same method as for cerium 3,5-dihydroxybenzoate using lutetium chloride ͑the formula of the Methods/Apparatus/Procedure: ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Lu C6H3 OH 2COO 3 ·7H2O . The solubility of samarium 3,5-dihydroxybenzoate in water was determined at 293 K. Saturated solutions were prepared under isothermal Estimated Errors: condition. After equilibrium had been established, samples of 1, 2, and Nothing speciﬁed. 5cm3 were removed and the concentration of Sm͑III͒ ions was determined gravimetrically using the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Samarium 3,5-dihydroxybenzoate was prepared by the same method as for ͑ ͒ 70 1 Praseodymium W. Brzyska and A. Kula, cerium 3,5-dihydroxybenzoate using samarium chloride ͑the formula of 3,5-dihydroxybenzoate Thermochim. Acta 277,29 the complex: ͓Sm͕C H ͑OH͒ COO͖ ͔·7H O͒. ͑ ͒ 6 3 2 3 2 tetrahydrate; C21H15O12Pr·4H2O; 1996 . ͓͔ Estimated Errors: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Nothing speciﬁed.

Variables: Prepared by: T/K=293 H. Miyamoto Components: Original Measurements: ͑1͒ Terbium 70W. Brzyska and A. Kula, Solubility of praseodymium 3,5-dihydroxybenzoate in water 3,5-dihydroxybenzoate Thermochim. Acta 277,29 heptahydrate; ͑1996͒. ͓͔ Temperature Solubility C21H15O12Tb·7H2O; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 2 / −3 T K10c1 mol dm Variables: Prepared by: 293 7.87 T/K=293 H. Miyamoto

Auxiliary Information Solubility of terbium 3,5-dihydroxybenzoate in water Methods/Apparatus/Procedure: Temperature Solubility The solubility of praseodymium 3,5-dihydroxybenzoate in water was determined at 293 K. Saturated solutions were prepared under isothermal / 2 / −3 T K10c1 mol dm condition. After equilibrium had been established, samples of 1, 2, and 5cm3 were removed and the concentration of Pr͑III͒ ions was determined 293 6.26 gravimetrically using the oxalate method.

Source and Purity of Materials: Auxiliary Information Praseodymium 3,5-dihydroxybenzoate was prepared by the same method as for cerium 3,5-dihydroxybenzoate using praseodymium chloride ͑the Methods/Apparatus/Procedure: ͓ ͕ ͑ ͒ ͖ ͔ ͒ formula of the complex: Pr C6H3 OH 2COO 3 ·4H2O . The solubility of terbium 3,5-dihydroxybenzoate in water was determined at 293 K. Saturated solutions were prepared under isothermal condition. Estimated Errors: After equilibrium had been established, samples of 1, 2, and 5 cm3 were Nothing speciﬁed. removed and the concentration of Tb͑III͒ ions was determined gravimetrically using the oxalate method.

Source and Purity of Materials: Components: Original Measurements: Terbium 3,5-dihydroxybenzoate was prepared by the same method as for ͑ ͒ 70 1 Samarium W. Brzyska and A. Kula, cerium 3,5-dihydroxybenzoate using terbium chloride ͑the formula of the 3,5-dihydroxybenzoate Thermochim. Acta 277,29 ͓ ͕ ͑ ͒ ͖ ͔ ͒ complex: Tb C6H3 OH 2COO 3 ·7H2O . heptahydrate; ͑1996͒. ͓͔ C21H15O12Sm·7H2O; Estimated Errors: ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 Nothing speciﬁed.

Variables: Prepared by: T/K=293 H. Miyamoto Components: Original Measurements: ͑1͒ Thulium 70W. Brzyska and A. Kula, Solubility of samarium 3,5-dihydroxybenzoate in water 3,5-dihydroxybenzoate Thermochim. Acta 277,29 heptahydrate; ͑1996͒. ͓͔ Temperature Solubility C21H15O12Tm·7H2O; ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5 / 2 / −3 T K10c1 mol dm Variables: Prepared by: 293 11.47 T/K=293 H. Miyamoto

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Solubility of thulium 3,5-dihydroxybenzoate in water Components: Original Measurements: 70 Temperature Solubility ͑1͒ Yttrium W. Brzyska and A. Kula, 3,5-dihydroxybenzoate Thermochim. Acta 277,29 / 2 / −3 ͑ ͒ T K10c1 mol dm heptahydrate; C21H15O12Y·7H2O; 1996 . ͓͔ 293 8.58 ͑ ͒ ͓ ͔ 2 Water; H2O; 7732-18-5

Variables: Prepared by: Auxiliary Information T/K=293 H. Miyamoto Methods/Apparatus/Procedure: The solubility of thulium 3,5-dihydroxybenzoate in water was determined Solubility of yttrium 3,5-dihydroxybenzoate in water at 293 K. Saturated solutions were prepared under isothermal condition. 3 After equilibrium had been established, samples of 1, 2, and 5 cm were Temperature Solubility removed and the concentration of Tm͑III͒ ions was determined / 2 / −3 gravimetrically using the oxalate method. T K10c1 mol dm

Source and Purity of Materials: 293 10.89 Thulium 3,5-dihydroxybenzoate was prepared by the same method as for cerium 3,5-dihydroxybenzoate using thulium chloride ͑the formula of the ͓ ͕ ͑ ͒ ͖ ͔ ͒ Auxiliary Information complex: Tm C6H3 OH 2COO 3 ·7H2O .

Estimated Errors: Methods/Apparatus/Procedure: Nothing speciﬁed. The solubility of yttrium 3,5-dihydroxybenzoate in water was determined at 293 K. Saturated solutions were prepared under isothermal condition. After equilibrium had been established, samples of 1, 2, and 5 cm3 were removed and the concentration of Y͑III͒ ions was determined Components: Original Measurements: gravimetrically using the oxalate method. ͑1͒ Ytterbium 70W. Brzyska and A. Kula, 3,5-dihydroxybenzoate Thermochim. Acta 277,29 Source and Purity of Materials: heptahydrate; ͑1996͒. Yttrium 3,5-dihydroxybenzoate was prepared by the same method as for ͓͔ ͑ C21H15O12Yb·7H2O; cerium 3,5-dihydroxybenzoate using yttrium chloride the formula of the ͑ ͒ ͓ ͔ ͓ ͕ ͑ ͒ ͖ ͔ ͒ 2 Water; H2O; 7732-18-5 complex: Y C6H3 OH 2COO 3 ·7H2O .

Variables: Prepared by: Estimated Errors: T/K=293 H. Miyamoto Nothing speciﬁed.

Solubility of ytterbium 3,5-dihydroxybenzoate in water

Temperature Solubility

/ 2 / −3 T K10c1 mol dm 3. Hydroxybenzoic Acids, Parabens, and 293 11.12 Hydroxybenzoic Acid Salts in Ternary Aqueous Systems Auxiliary Information 3.1. Hydroxybenzoic acid–water–organic Methods/Apparatus/Procedure: compound systems The solubility of ytterbium 3,5-dihydroxybenzoate in water was determined at 293 K. Saturated solutions were prepared under isothermal 3.1.1. Salicylic acid condition. After equilibrium had been established, samples of 1, 2, and 3.1.1.1. Halides 5cm3 were removed and the concentration of Yb͑III͒ ions was determined gravimetrically using the oxalate method. Components: Original Measurements: Source and Purity of Materials: ͑1͒ Benzoic acid, 2-hydroxy- 71E. Cohen and W. D. J. van Ytterbium 3,5-dihydroxybenzoate was prepared by the same method as for ͑o-hydroxybenzoic acid; salicylic Dobbenburgh, Z. Phys. Chem. cerium 3,5-dihydroxybenzoate using ytterbium chloride ͑the formula of ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 59-72-7 118,37 1925 . the complex: ͓Yb͕C H ͑OH͒ COO͖ ͔·7H O͒. ͑ ͒ ͓ ͔ 6 3 2 3 2 2 Water; H2O; 7732-18-5 ͑3͒ Trichloromethane Estimated Errors: ͑ ͒ ͓ ͔ chloroform ; CHCl3; 67-66-3 Nothing speciﬁed. Variables: Prepared by: Composition E. Königsberger and L.-C. t/ °C=30.5 Königsberger

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Solubility of salicylic acid in water–chloroform mixtures Solubility of salicylic acid in water–carbon tetrachloride mixtures

Concentration Concentration

Temperature of chloroform Solubility Temperature of CCl4 Solubility

c c Shaking 100w1 Shaking 100w1 / 5 a b ͑ ͒ / 5 a b ͑ ͒ t °C time/h 10 w2 100w1 100w1 compiler t °C time/h 10 w2 100w1 100w1 compiler

30.5 3 0 1.55 1.56 1.56 30.5 3 0 0.36 0.35 0.36 5 0 1.56 1.55 1.56 5 0 0.35 0.35 0.35 3 35.4 1.64 1.63 1.64 3 8.7 0.35 0.36 0.36 3 60.8 1.69 1.68 1.69 3 22.7 0.36 0.36 0.36 3 108.1 1.72 1.71 1.72 3 65.9 0.36 0.37 0.37 3 saturated 1.73 1.72 1.73 3 saturated 0.36 0.36 0.36

aAn undersaturation method was used to determine the solubility. aAn undersaturation method was used to determine the solubility. bA supersaturation method was used to determine the solubility. bA supersaturation method was used to determine the solubility. c a b c a b The mean value was calculated from the w1 and w1 values. The mean value was calculated from the w1 and w1 values.

Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: In parallel experiments, dry chloroform and chloroform containing a The experimental detail is given in the compilation of Ref. 71 for the known amount of water were added to dry salicylic acid contained in two salicylic acid–chloroform–water system. carefully dried, weighed bottles. These were shaken in an Ostwald thermostat for 5–6 h at 30.5 °C. After settling of the solid phase, two Source and Purity of Materials: samples of the supernatant solution were taken using a glass tube Salicylic acid ͑Kahlbaum͒ was recrystallized from dry ether, ground, and containing some cotton wool. The samples were weighed, the chloroform kept in a desiccator over P4O10. Water was distilled from a tin-coated was evaporated by a dry air stream and the dry residues were weighed apparatus. Sulfur-free CCl4 was kept with P4O10 for several days, then again. distilled slowly.

Source and Purity of Materials: Estimated Errors: Salicylic acid ͑Kahlbaum͒ was recrystallized from dry ether, ground, and Not stated.

kept in a desiccator over P4O10. Water was distilled from a tin-coated apparatus. Chloroform was kept with P4O10 for several days, then distilled slowly.

Estimated Errors: Not stated. 3.1.1.2. Alcohols

Components: Original Measurements: Components: Original Measurements: 71 ͑1͒ Benzoic acid, 2-hydroxy- E. Cohen and W. D. J. van ͑1͒ Benzoic acid, 2-hydroxy- 23Fr. Hoffmann and K. Langbeck, ͑o-hydroxybenzoic acid; salicylic Dobbenburgh, Z. Phys. Chem. ͑o-hydroxybenzoic acid; salicylic Z. Phys. Chem. 51,385͑1905͒. acid͒;CH O ; ͓69-72-7͔ 118,37͑1925͒. ͒ ͓ ͔ 7 6 3 acid ;C7H6O3; 69-72-7 ͑2͒ Water; H O; ͓7732-18-5͔ ͑ ͒ ͓ ͔ 2 2 Ethanol; C2H6O; 64-17-5 ͑3͒ Tetrachloromethane ͑carbon ͑3͒ Water; H O; ͓7732-18-5͔ ͒ ͓ ͔ 2 tetrachloride ;CCl4; 56-23-5 Variables: Prepared by: Variables: Prepared by: Concentration of ethanol E. Königsberger and L.-C. Composition E. Königsberger and L.-C. t/ °C=24.89 and 34.82 Königsberger t/ °C=30.5 Königsberger

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Solubility of salicylic acid in water–ethanol mixtures Components: Original Measurements: 24 Concentration Solubility ͑1͒ Benzoic acid, 2-hydroxy- A. Seidell, Trans. Am. Temperature of ethanol Solubilitya change ͑o-hydroxybenzoic acid; salicylic Electrochem. Soc. 13,319 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1908 . 2 / −1 ͑ ͒ ͓ ͔ 10 m1 mol kg 2 Ethanol; C2H6O; 64-17-5 / 2 / −1 4 ͑ ͒ b ͑ ͒ ͓ ͔ t °C 10 x2 m2 mol kg 10 x1 compiler % 3 Water; H2O; 7732-18-5

24.89 0 0 2.8851c 1.602c 100.00 Variables: Prepared by: 0.037 04 0.020 57 2.8931 1.607 100.27 Concentration of ethanol A. Goto and H. Miyamoto 0.044 88 0.024 92 2.8966 1.609 100.40 t/ °C=25 0.072 87 0.040 48 2.9083 1.616 100.80 0.099 99 0.055 56 2.9150 1.620 101.04 Solubility of salicylic acid in water–ethanol mixtures 0.146 90 0.081 66 2.9343 1.632 101.70 0.313 79 0.174 74 2.9901 1.666 103.64 Concentration Sp. Gr. of 0.459 57 0.256 30 3.0396 1.696 105.35 Temperature of ethanol satd. soln. Solubility 0.677 90 0.378 89 3.1064 1.737 107.67 / −1 1.399 50 0.787 97 3.3549 1.889 116.28 x2 m1 mol kg / ͑ ͒ ͑ ͒ 1.888 5 1.068 6 3.5279 1.997 122.28 t °C 100w2 compiler d 100w1 compiler 2.197 5 1.247 4 3.6509 2.073 126.54 25 0.00 0.00 1.001 0.22 0.016 2.865 3 1.637 7 3.9253 2.244 136.05 8.90 3.68 0.986 0.336 0.0244 c c 34.82 0 0 4.1844 2.324 100.00 32.00 15.54 0.957 2.68 0.199 0.044 67 0.024 80 4.2044 2.336 100.48 51.00 28.93 0.945 12.82 1.065 0.050 46 0.028 02 4.2062 2.337 100.52 70.2 47.95 0.941 24.01 2.288 0.059 66 0.033 15 4.2093 2.339 100.59 88.0 74.14 0.932 31.03 3.257 0.101 55 0.056 43 4.2348 2.354 101.21 96.30 91.05 0.923 32.45 3.478 0.203 85 0.113 40 4.2982 2.392 102.72 99.80 99.49 0.919 33.20 3.598 0.430 18 0.239 87 4.4341 2.473 105.97 0.867 9 0.486 10 4.6993 2.633 112.31 1.332 5 0.762 11 4.9886 2.808c 119.22 Auxiliary Information 1.752 8 0.990 60 5.2816 2.986 126.22 Methods/Apparatus/Procedure: aThe molality solubility of salicylic acid was calculated from the equation The saturation of the solutions was accomplished by moderate agitation of ͑ / ͒/͑ ͒ the mixtures of solute and solvent enclosed in tubes immersed in a m1 = x1 M3 1−x1 −x2 by the compilers. b constant-temperature water bath maintained at 25 °C. The attainment of with respect to pure water. equilibrium was ensured by analyzing solutions which had been agitated c ͑ ͑ ͒/͑ Inconsistency in original data the difference between m1= 55.511x1 1 for different lengths of time. The equilibrium had been reached for 3 days. ͒ ͑ ͒ ͒ −x1 −x2 and m1 = 55.511x1 is larger than 0.5% . The analyses were made by titrating aliquot portions of the portions of the solutions with standard alkali phenolphthalein as indicator. Auxiliary Information Source and Purity of Materials: Methods/Apparatus/Procedure: Salicylic acid was pure white crystals with melting point of 156 °C. By Suspensions were shaken in carefully cleaned ͑steamed͒ glass bottles with titration with standard alkali solution, it corresponded to 100% purity. rubber stoppers placed in an Ostwald thermostat ͑times not specified͒. After the solid phase had settled, filtration at equilibrium temperature was Estimated Errors: performed by pressing the solution through a glass tube filled with glass Nothing specified. wool. The filtrate, the first 20 cm3 of which was discarded, was weighed ͑ ͒ and titrated with Ba OH 2 solution using phenolphthalein as indicator. Care was taken to avoid contamination of Ba͑OH͒ with atmospheric 2 Components: Original Measurements: CO . 2 ͑1͒ Benzoic acid, 2-hydroxy- 20R. Wright, J. Chem. Soc. 1927, Source and Purity of Materials: ͑o-hydroxybenzoic acid; salicylic 1334. ͒ ͓ ͔ Salicylic acid ͑Kahlbaum͒ was recrystallized repeatedly from water and acid ;C7H6O3; 69-72-7 ͑ ͒ ͓ ͔ then from ethanol, m.p. 156 °C. Ethanol ͑Kahlbaum͒ 99.8%. 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Estimated Errors: Solubility: nothing specified. Variables: Prepared by: Temperature: precision Ϯ0.03 K. Concentration of ethanol A. Goto and H. Miyamoto t/ °C=20 and 30

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Solubility of salicylic acid in water–ethanol mixtures Auxiliary Information

Temperature Solubility Methods/Apparatus/Procedure: The saturated solutions were prepared in stoppered tubes in a thermostat, / −1 100w1 m1 mol kg the weighed portions were taken, and the amount of solute was estimated t/ °CSolvent Original dataa ͑compiler͒ ͑compiler͒ either by titration or by evaporation to dryness.

20 Water 0.21 0.21 Source and Purity of Materials: 0.23 0.23 No information was given. Av. 0.22 0.22 0.016 50% Ethanol 11.8 10.6 Estimated Errors: Ϯ 11.8 10.6 Solubility: precision 0.0–4.5 Av. 11.8 10.6 0.854 Temperature: nothing speciﬁed. Ethanol 51.0 33.8 52.0 34.2 Av. 51.5 34.0 3.73 Components: Original Measurements: 31 30 Water 0.30 0.30 ͑1͒ Benzoic acid, 2-hydroxy- J.O. Halford, J. Am. Chem. ͑ ͑ ͒ 0.32 0.32 o-hydroxybenzoic acid; salicylic Soc. 55, 2272 1933 . ͒ ͓ ͔ Av. 0.31 0.31 0.022 acid ;C7H6O3; 69-72-7 ͑2͒ Ethanol; C H O; ͓64-17-5͔ 50% Ethanol 17.9 15.2 2 6 ͑3͒ Water; H O; ͓7732-18-5͔ 18.0 15.3 2 Av. 18.0 15.2 1.30 Variables: Prepared by: Ethanol 57.0 53.9 Concentration of ethanol A. Goto and H. Miyamoto 57.5 54.4 t/ °C=25 Av. 57.3 54.2 4.15 aIn original paper, the solubility was given as grams of solute per 100 g of solvent.

Solubility of salicylic acid in water–ethanol mixtures

Concentration of Temperature ethanol Solubility

Average / −3 100x2 Speciﬁc Undersaturation Supersaturation c1 mol dm / ͑ ͒ / −3 / −3 ͑ ͒ t °C 100w2 compiler gravity c1 mol dm c1 mol dm compiler

25 0 0 1.011 0.0153 0.0153 0.0153 18.8 6.85 0.982 0.0388 0.0389 0.0389 37.5 19.0 0.950 0.332 0.329 0.331 56.2 33.5 0.949 1.070 1.063 1.067 75.0 54.0 0.949 1.806 1.802 1.804 93.8 85.5 0.922 2.194 2.192 2.193

Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 2-hydroxy- 72I.L. Krupatkin, Sbornik Statei The saturated solutions were obtained by shaking an excess of the acid ͑o-hydroxybenzoic acid; salicylic po Obshchei. Khim., Akad. Nauk ͒ ͓ ͔ ͑ ͒ with the solvent for 24 h in a thermostat at 25 °C. The salicylic acid acid ;C7H6O3; 69-72-7 S.S.S.R. I,151 1953 . ͑ ͒ ͓ ͔ measurements were run in pairs, the second solution being supersaturated 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ by heating before immersion in the oil bath. Both the undersaturation and 3 Water; H2O; 7732-18-5 the supersaturation methods were performed to approach equilibrium. The titration of the acid with sodium hydroxide standardized against benzoic Variables: Prepared by: acid was carried out electrometrically with the quinhydrone electrode. Composition and temperature A. Goto and H. Miyamoto

Source and Purity of Materials: No information is given.

Estimated Errors: Solubility: nothing speciﬁed. Temperature: precision Ϯ0.05 °C.

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Solubility of salicylic acid in water–ethanol mixtures Solubility of salicylic acid in water–ethanol mixtures

Composition of Composition of Temperature saturated solutions Temperature saturated solutions

Demixing Crystallization Ethanol Water Demixing Crystallization Ethanol Water

Section temperature temperature Salicylic acid 100w2 100w3 Section temperature temperature Salicylic acid 100w2 100w3 / / ͑ ͒ ͑ ͒ / / ͑ ͒ ͑ ͒ number t °C t °C 100w1 compiler compiler number t °C t °C 100w1 compiler compiler

1 — 128.5 88.97 0.55 10.48 7 137.0 90.00 8.00 2.00 Ethanol 5% — 116.0 79.68 1.02 19.30 Ethanol 80% 119.0 80.06 15.95 3.99 Water 95% — 108.0 68.76 1.56 29.68 Water 20% 101.0 70.10 26.92 5.98 71.0 — 62.62 1.87 35.51 83.0 59.94 32.05 8.01 74.0 103.0 60.00 2.00 38.00 64.0 50.14 39.89 9.97 81.0 101.0 50.00 2.50 47.50 43.0 39.89 48.09 12.02 82.5 99.0 40.00 3.00 57.00 82.0 99.0 29.06 3.55 67.39 Auxiliary Information 78.5 — 17.67 4.12 78.21 72.0 — 9.88 4.51 85.61 Methods/Apparatus/Procedure: 65.0 — 7.01 4.65 88.34 The experiment was performed by the polythermic method. 2 — 107.0 68.82 3.12 28.06 Ethanol 10% 68.0 — 61.44 3.86 34.70 Source and Purity of Materials: Water 90% 73.0 101.5 56.98 4.30 38.72 Chemically pure grade salicylic acid with b.p. 155 °C was used. Ethanol was distilled twice. The boiling point of the ethanol was 78 °C. Water 76.0 97.0 47.26 5.27 47.47 was distilled twice. 75.0 95.0 34.65 6.535 58.815 73.0 93.0 28.31 7.17 64.52 Estimated Errors: 67.0 — 14.46 8.55 76.99 Nothing speciﬁed. 62.5 84.0 10.00 9.00 81.00 56.0 — 9.00 9.10 81.90 — 78.03 4.99 9.50 85.51 Components: Original Measurements: 3 — 128.5 89.64 1.55 8.81 ͑1͒ Benzoic acid, 2-hydroxy- 40A.N. Paruta, B.J. Sciarrone, and Ethanol 15% — 114.5 79.64 3.05 17.31 ͑o-hydroxybenzoic acid; salicylic N.G. Lordi, J. Pharm. Sci. 53, Water 85% ͒ ͓ ͔ ͑ ͒ 64.0 — 61.14 5.83 33.03 acid ;C6H7O3; 69-72-7 1349 1964 . 65.0 99.5 60.00 6.00 34.00 ͑2͒ 1-Propanol ͑n-propyl ͒ ͓ ͔ 71.0 — 54.45 6.83 38.72 alcohol ;C3H8O; 71-23-8 ͑ ͒ ͓ ͔ 71.0 96.0 49.57 7.56 42.87 3 Water; H2O; 7732-18-5 70.0 — 40.00 9.00 51.00 Variables: Prepared by: 65.0 — 29.65 10.55 59.80 t/ °C=30.6 A. Goto and R. Goto 59.0 — 19.95 12.01 68..04 55.0 — 15.87 12.62 71.51 4 — 131.0 90.84 2.29 6.87 Solubility of salicylic acid in water–1-propanol mixtures Ethanol 25% — 103.0 69.37 7.66 22.97 b Water 75% 61.0 — 54.71 11.32 33.97 Temperature Solubility

61.0 — 53.46 11.635 34.905 ␥ / −3 / −3 Dielectric 1 gdm c1 mol dm 61.0 83.0 48.63 12.84 38.53 t/ °C constanta ͑compiler͒ ͑compiler͒ 59.0 — 40.00 15.00 45.00

52.0 — 29.70 17.575 52.725 30.6 22.3 320 2.32 39.0 — 19.34 20.16 60.49 5 5 aThe dielectric constant of the binary mixtures at the maximum solubility of 5 130.0 89.50 4.20 6.30 salicylic acid. Ethanol 40% 111.0 77.75 8.90 13.35 bIn the original paper, the solubility was given as mg/ml of solution. The ␥ Water 60% 99.0 68.89 12.44 18.67 1 value was calculated by the compiler. 88.0 59.44 16.22 24.34 80.0 49.75 20.10 30.15 Auxiliary Information 75.0 40.45 23.82 35.73 67.0 31.30 27.48 41.22 Methods/Apparatus/Procedure: 58.0 21.41 31.44 47.15 The solubility of salicylic acid was determined in aqueous solvent 40.0 9.85 36.06 54.09 mixtures using 15 ml screw-capped vials fitted with Teflon liners. The 6 135.0 90.11 5.93 3.96 vials were attached to a rotating wheel in a water bath maintained at 30.6 °C. Equilibration for 24 h was sufficient. Samples were withdrawn Ethanol 60% 117.0 80.02 11.99 7.99 from the reaction vials using a pipet fitted with a glass wool filtering plug. Water 40% 99.0 69.91 18.05 12.04 The solubility of salicylic acid was determined by base titration using 81.0 60.13 23.92 15.95 freshly prepared 0.1 mol dm−3 NaOH as titrant and phenolphthalein as an 67.0 50.00 30.00 20.00 indicator. The dielectric constants of all solvent systems were measured by 54.0 39.92 36.05 24.03 a resonance method at 25 °C.

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Source and Purity of Materials: Source and Purity of Materials: The solvents were purified by the method described by A. Weissberger et Chemical 2-propanol ͑British Drug Houses͒ was treated with calcium al., Organic Solvents, 2nd ed. ͑Interscience, New York, 1955͒, Chaps. 4 oxide and fractionally distilled under anhydrous conditions. Mixtures of and 5. purified 2-propanol and distilled water were prepared by weight. Salicylic acid was recrystallized twice from 70% ethanol and dried in a vacuum Estimated Errors: oven at 60 °C. Solubility: nothing specified. Temperature: precision Ϯ0.2 °C ͑solubility͒ and Ϯ1.0 °C ͑dielectric Estimated Errors: constant͒. Solubility: nothing specified. Temperature: precision Ϯ0.1 °C.

Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 34N.A. Hall, Am. J. Pharm. 132, Components: Original Measurements: ͑o-hydroxybenzoic acid; salicylic 406 ͑1960͒. ͑1͒ Benzoic acid, 2-hydroxy- 23Fr. Hoffmann and K. Langbeck, ͒ ͓ ͔ ͑ ͑ ͒ acid ;C7H6O3; 69-72-7 o-hydroxybenzoic acid; salicylic Z. Phys. Chem. 51,385 1905 . ͑ ͒ ͑ ͒ ͓ ͔ 2 2-Propanol isopropanol; acid ;C7H6O3; 69-72-7 ͒ ͑ ͒ isopropyl alcohol ;C3H8O; 2 1-Propanol, 2-methyl ͓67-63-0͔ ͑isobutanol; isobutyl alcohol͒; ͑ ͒ ͓ ͔ ͓ ͔ 3 Water; H2O; 7732-18-5 C4H10O; 78-83-1 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Variables: Prepared by: Concentration of 2-propanol A. Goto and R. Goto Variables: Prepared by: t/ °C=25 Concentration of isobutyl alcohol A. Goto and H. Miyamoto t/ °C=24.89 and 34.82

Solubility of salicylic acid in water–2-propanol mixtures Solubility of salicylic acid in water–isobutyl alcohol mixtures Temperature Concentration of 2-propanol Solubilitya Concentration Solubility ␥ / −3 / −3 a x2 1 gdm c1 mol dm Temperature of isobutyl alcohol Solubility change / ͑ ͒ ͑ ͒ ͑ ͒ t °C w2 compiler compiler compiler 2 / −1 10 m1 mol kg 25 0 0 2.24 0.0162 / 2 / −1 4 ͑ ͒ b t °C 10 x2 m2 mol kg 10 x1 compiler % 10 3.2 3.73 0.0270 20 7.0 10.99 0.0796 24.89 0 0 2.8851 1.602 100.00 30 11 46.4 0.336 0.036 02 0.020 00 2.9090 1.616 100.83 40 17 99.9 0.723 0.044 58 0.024 76 2.9159 1.620 101.09 50 23 157.7 1.142 0.059 30 0.032 94 2.9334 1.630 101.67 60 31 207.4 1.502 0.091 19 0.050 62 2.9547 1.642 102.41 70 41 257.3 1.863 0.180 23 0.100 23 3.0330 1.687 105.13 80 55 293.7 2.126 0.453 84 0.253 09 3.2648 1.821 113.16 90 73 314 2.273 0.926 00 0.318 89 3.7179 2.084 128.66 34.82 0 0 4.1844 2.324 100.00 aIn the original data, the solubility was given as grams per 100 ml of solu- 0.036 01 0.020 00 4.2295 2.350 101.08 tion. 0.045 14 0.025 07 4.2379 2.355 101.28 0.059 29 0.032 94 4.2634 2.369 101.89 Auxiliary Information 0.090 30 0.050 18 4.2983 2.389 102.72 0.180 91 0.100 62 4.4347 2.467 105.89 Methods/Apparatus/Procedure: 0.465 66 0.259 76 4.8391 2.700 115.65 A triplicate series of test tubes containing known concentration of aqueous 2-propanol solution was prepared, and to each tube, an excess of 0.933 08 0.523 02 5.6236 3.153 134.40

powdered salicylic acid was added. The tubes were closed with previously a washed rubber stoppers, shaken vigorously for three minutes, and set The molality solubility of salicylic acid was calculated from the equation, ͑ / ͒/͑ ͒ aside for 3 weeks at room temperature ͑approximately 29 °C͒. During the m1 = x1 M3 1−x1 −x2 . waiting period, the samples were shaken at least once daily with care to bWith respect to pure water. assure the dispersion of the compacted mass of salicylic acid at the bottom of the tube. The samples were placed in a thermostatically Auxiliary Information controlled water bath at 25 °C for another 2 weeks during which time daily shaking was continued. Evidence of attainment of saturated Methods/Apparatus/Procedure: equilibrium was shown when the assay of the sample containing 50% The experimental detail is given in the compilation of Ref. 23 for the 2-propanol was the same on two subsequent days. The solutions were salicylic acid–ethanol–water system. assayed for salicylic acid after removal of a sample with a pipe protected Source and Purity of Materials: against withdrawal of undissolved crystals by glass wool. All solutions ͑ ͒ were titrated with standard sodium hydroxide solution. In addition, those Salicylic acid Kahlbaum was recrystallized repeatedly from water and containing distilled water alone and 10% isopropanol were analyzed then from ethanol, m.p. 156 °C. Isobutyl alcohol was double distilled at colorimetrically. The average of triplicate determination was obtained. 106–107 °C.

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Estimated Errors: Solubility of salicylic acid in water–formic acid mixtures Solubility: nothing speciﬁed, Temperature: precision Ϯ0.03 K. Concentration Temperature of formic acida Solubilityb, c ͑Av.d =0.016 32 mol dm−3͒

2 / −3 Original 10 c1 mol dm / ␥ / −3 t °C % data 1 gdm Gravimetric Volumetric

25 0 0.0563 2.252 1.631 1.634 3.1.1.3. Ketones and acids 0.24 — — — 1.531 0.46 — — — 1.474 0.625 0.0512 2.048 1.484 — Components: Original Measurements: 1.25 0.0515 2.060 1.496 — ͑ ͒ 40 1 Benzoic acid, 2-hydroxy- A.N. Paruta, B.J. Sciarrone, and 2.5 0.0530 2.120 1.536 — ͑o-hydroxybenzoic acid; salicylic N.G. Lordi, J. Pharm. Sci. 53, 5 0.0592 2.368 1.716 — acid͒;CH O ; ͓69-72-7͔ 1349 ͑1964͒. 6 7 3 10 0.0725 2.900 2.101 — ͑2͒ 2-Propanone ͑acetone͒; ͓ ͔ C3H6O; 67-64-1 a ͑ ͒ ͓ ͔ No specific information on mass or volume percent was stated in the origi- 3 Water; H2O; 7732-18-5 nal paper. Variables: Prepared by: bIn the original paper, the solubility was given as grams per 25 cm3 of the t/ °C=30.6 A. Goto and R. Goto saturated solution. cThe concentration of the acid was given as “Normality” units. d ͑ ␥ ͒ Solubility of salicylic acid in water–acetone mixture The average in pure water was calculated from c1 Calc. by using 1 , c1 ͑ ͒ ͑ ͒ Gravimetric , and c1 Volumetric by the compiler. Temperature Solubilityb Auxiliary Information ␥ / −3 / −3 1 gdm c1 mol dm t/ °C Solvent system Dielectric constanta ͑compiler͒ ͑compiler͒ Methods/Apparatus/Procedure: Salicylic acid crystals were placed in a glass-stoppered bottle with solvent. 30.6 Water 78.5 3 0.022 The bottles were rotated in a thermostat for several days. A measured Water-acetone 25.0 387 2.78 quantity was removed by a pipet fitted with a filter-cover to prevent the entrance of any crystals. The solution was evaporated to dryness and then aThe dielectric constant of the binary mixtures at the maximum solubility of the product was weighed. In the dilute solution, the acid concentration salicylic acid. was determined by titration with barium hydroxide solution using b ␥ phenolphthalein as an indicator. In the original paper, the solubility was given as mg/ml of solution. The 1 value was calculated by the compiler. Source and Purity of Materials: Salicylic acid was recrystallized from freshly distilled water. Formic acid Auxiliary Information was purified by distilling. Methods/Apparatus/Procedure: Estimated Errors: The experimental detail is given in the compilation of Ref. 40 for the Solubility: precision Ϯ0.2%–0.4%. salicylic acid–1-propanol–water system in Sec. 3.1.1.2. Temperature: precision Ϯ0.1 °C. Source and Purity of Materials: The solvent was purified by the method described by A. Weissberger et al., Organic Solvents, 2nd ed. ͑Interscience, New York, 1955͒, Chaps. 4 Components: Original Measurements: and 5. ͑1͒ Benzoic acid, 2-hydroxy- 27J. Kendall, Proc. R. Soc. ͑o-hydroxybenzoic acid; salicylic London Ser. A 85,200͑1911͒. Estimated Errors: ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 Solubility: nothing specified. ͑ ͒ 2 Acetic acid; C2H4O2; Temperature: precision Ϯ0.1 °C. ͓64-19-7͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-28-5

Variables: Prepared by: Components: Original Measurements: Concentration of acetic acid A. Goto and H. Miyamoto ͑1͒ Benzoic acid, 2-hydroxy- 27J. Kendall, Proc. R. Soc. t/ °C=25 ͑o-hydroxybenzoic acid; salicylic London Ser. A 85, 200 ͑1911͒. ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 ͑ ͒ 2 Formic acid; CH2O2; ͓64-18-6͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-28-5

Variables: Prepared by: Concentration of formic acid A. Goto and H. Miyamoto t/ °C=25

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Solubility of salicylic acid in water–acetic acid mixtures Auxiliary Information

Concentration Methods/Apparatus/Procedure: Temperature of acetic acida Solubilityb,c ͑Av.d =0.016 32 mol dm−3͒ The water or aqueous sodium carboxylate solution was put into a small flask and excess of salicylic acid was added. The flask was corked and 2 / −3 Original 10 c1 mol dm placed into a thermostat. The supersaturation method was used. The flasks / ␥ / −3 t °C % data 1 gdm Gravimetric Volumetric were shaken at a higher temperature, so that on cooling to 26.4 °C in the thermostat, the acid was crystallized out in a state of fine division. 25 0 0.0563 2.252 1.631 1.634 Equilibrium was reached in about 3 h. Portions of the saturated solution 0.625 0.0584 2.336 1.691 — were withdrawn by a pipet through a plug of cotton wool and introduced 1.25 0.0602 2.408 1.745 — into Jena flasks. The concentration of each solution was determined by 2.5 0.0636 2.544 1.846 — titration with sodium hydroxide solution using phenolphthalein as an 5 0.0710 2.840 2.059 — indicator.

aNo specific information on mass or volume percent was stated in the origi- Source and Purity of Materials: nal paper. Salicylic acid and sodium salts used as a solvent were obtained from bIn the original paper, the solubility was given as grams per 25 cm3 of the Kahlbaum. The purity of salicylic acid was characterized by the solubility saturated solution. of 0.0171 mol dm−3 at 26.4 °C and the value was identical to that given c The concentration of the acid was given as “Normality” units. in Ref. 23. d ͑ ␥ ͒ The average in pure water was calculated from c1 Calc. by using 1 , c1 ͑Gravimetric͒,andc ͑Volumetric͒ by the compiler. Estimated Errors: Solubility: nothing specified. Auxiliary Information Temperature: precision Ϯ0.1 °C. Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 27 for the salicylic acid–formic acid–water system. Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 26J.C. Philip and F.B. Garner, J. Source and Purity of Materials: ͑o-hydroxybenzoic acid; salicylic Chem. Soc. Trans. 95, 1466 ͒ ͓ ͔ ͑ ͒ Salicylic acid was recrystallized from freshly distilled water. Formic acid acid ;C7H6O3; 69-72-7 1909 . was purified by distilling. ͑2͒ Formic acid, sodium salt ͑ ͒ sodium formate ; CHO2Na; Estimated Errors: ͓141-53-7͔ Solubility: precision Ϯ0.2%–0.4%. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Temperature: precision Ϯ0.1 °C. Variables: Prepared by: Concentration of sodium formate A. Goto, R. Goto, and H. t/ °C=26.4 Miyamoto

Solubility of salicylic acid in water–sodium formate mixtures 3.1.1.4. Organic salts Temperature Concentration of sodium formate Solubility

Components: Original Measurements: / 2 / −3 2 / −3 t °C 10 c2 mol dm 10 c1 mol dm ͑1͒ Benzoic acid, 2-hydroxy- 37J.C. Philip, J. Chem. Soc. ͑o-hydroxybenzoic acid; salicylic Trans. 87,987͑1905͒. 26.4 0.00 1.64 ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 1.19 2.46 ͑2͒ Formic acid, sodium salt 2.40 3.20 ͑ ͒ sodium formate ; CHO2Na; 5.97 5.15 ͓ ͔ 141-53-7 11.97 7.56 ͑ ͒ ͓ ͔ 3 Water H2O; 7732-18-5

Variables: Prepared by: Auxiliary Information Concentration of sodium formate A. Goto, R. Goto, and H. t/ °C=26.4 Miyamoto Methods/Apparatus/Procedure: The solubility determination was carried out at 25 °C, and the procedure was identical to that described in Ref. 37. Solubility of salicylic acid in water–sodium formate mixtures Source and Purity of Materials: Temperature Concentration of sodium formate Solubility The detail is given in the compilation of Ref. 37 for the salicylic acid– / / −3 / −3 formic acid sodium salt–water system. t °C c2 mol dm c1 mol dm Estimated Errors: 26.4 0.0000 0.0171 Solubility: nothing speciﬁed. 0.0122 0.0251 Temperature: precision Ϯ0.1 °C. 0.0244 0.0339 0.0610 0.0535

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Solubility of salicylic acid in water–sodium formate mixtures Components: Original Measurements: 18 ͑1͒ Benzoic acid, 2-hydroxy- S.S. Doosaj and W.V. Bhagwat, Temperature Concentration of sodium formate Solubility ͑o-hydroxybenzoic acid; salicylic J. Indian Chem. Soc. 10,225 ͒ ͓ ͔ ͑ ͒ / / −3 2 / −3 acid ;C7H6O3; 69-72-7 1933 ; t °C c2 mol dm 10 c1 mol dm ͑2͒ Formic acid, sodium salt 19W.V. Bhagwat and S.S. Doosaj, ͑ ͒ 25 0 1.601 sodium formate ; CHO2Na; J. Indian Chem. Soc. 10,477 ͓141-53-7͔ ͑1933͒. 0.0500 4.59 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 0.1000 6.76

Variables: Prepared by: Concentration of sodium formate A. Goto, R. Goto, and H. Auxiliary Information t/ °C=30 Miyamoto Methods/Apparatus/Procedure: Laboratory-glass flasks were filled with salt solutions and an excess of Solubility of salicylic acid in water–sodium formate mixtures solid acid. The mixtures were kept in a thermostat and vigorously shaken by hand from time to time. Every 24 h, a known, filtered amount of −3 ͑ ͒ Concentration solution was titrated with approximately 0.025 mol dm Ba OH 2 with Temperature of sodium formate Solubilitya phenolphthalein as indicator. Each solubility value is the average of at least two independent determinations which deviated from each other by / −3 2 / −3 c2 mol dm 10 c1 mol dm Ͻ1%. / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ t °C 2 gdm compiler 1 gdm compiler Source and Purity of Materials: 30 0.0000 0.000 0 2.743 0.019 86 Salicylic acid was from Kahlbaum. 4.6456 0.068 31 8.624 0.062 44 6.8578 0.100 84 10.35 0.074 93 Estimated Errors: 9.0009 0.132 35 12.08 0.087 46 Solubility: precision Ͻ1%. 13.0922 0.192 51 15.15 0.109 7 Temperature: precision Ϯ0.1 K. 24.0024 0.352 94 21.04 0.152 3 33.2340 0.488 68 26.36 0.190 8 36.0035 0.529 41 27.07 0.196 0 Components: Original Measurements: 48.0047 0.705 87 32.02 0.231 8 ͑1͒ Benzoic acid, 2-hydroxy- 26J.C. Philip and F.B. Garner, J. 72.0071 1.058 81 39.87 0.288 7 ͑o-hydroxybenzoic acid; salicylic Chem. Soc. Trans. 95, 1466 ͒ ͓ ͔ ͑ ͒ 144.0142 2.117 62 63.66 0.460 9 acid ;C7H6O3; 69-72-7 1909 . ͑2͒ Formic acid, potassium salt a ␥ ␥ ͑ ͒ In the original data, the values 1 and 2 were given as grams per liter of potassium formate ; CHO2K; ͓ ͔ solution. 590-29-4 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Auxiliary Information Variables: Prepared by: Methods/Apparatus/Procedure: Concentration of potassium A. Goto, R. Goto, and H. No information was given. formate Miyamoto t/ °C=25 Source and Purity of Materials: No information was given. Solubility of salicylic acid in water–potassium formate mixtures Estimated Errors: Nothing specified. Temperature Concentration of potassium formate Solubility

/ / −3 2 / −3 t °C c2 mol dm 10 c1 mol dm

Components: Original Measurements: 25 0 1.64 ͑1͒ Benzoic acid 2-hydroxy- 30E. Larsson, Z. Phys. Chem. 1.22 2.45 ͑o-hydroxybenzoic acid; salicylic 127, 233 ͑1927͒. 3.05 3.57 ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 6.10 5.16 ͑2͒ Sodium methanoate ͑sodium ͒ ͓ ͔ formate ; CHO2Na; 141-53-7 ͑ ͒ ͓ ͔ Auxiliary Information 3 Water; H2O; 7732-18-5

Variables: Prepared by: Methods/Apparatus/Procedure: Concentration of sodium formate E. Königsberger and L.-C. The experimental detail is given in the compilation of Ref. 26 for the t/ °C=25 Königsberger salicylic acid–sodium formate–water system.

Source and Purity of Materials: The detail is given in the compilation of Ref. 26 for the salicylic acid– sodium formate–water system.

Estimated Errors: Solubility: nothing speciﬁed.

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Temperature: precision Ϯ0.1 °C. Auxiliary Information

Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 26 for the Components: Original Measurements: salicylic acid–sodium formate–water system. ͑1͒ Benzoic acid, 2-hydroxy- 37J.C. Philip, J. Chem. Soc. ͑o-hydroxybenzoic acid; salicylic Trans. 87,987͑1905͒. Source and Purity of Materials: ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 The detail is given in the compilation of Ref. 26 for the salicylic acid– ͑ ͒ 2 Acetic acid, sodium salt sodium formate–water system. ͑ ͒ sodium acetate ;C2H3O2Na; ͓127-09-3͔ Estimated Errors: ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Solubility: nothing speciﬁed. Temperature: precision Ϯ0.1 °C. Variables: Prepared by: Concentration of sodium acetate A. Goto, R. Goto, and H. t/ °C=26.4 Miyamoto Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 18S.S. Doosaj and W.V. Bhagwat, Solubility of salicylic acid in water–sodium acetate mixtures ͑o-hydroxybenzoic acid; salicylic J. Indian Chem. Soc. 10,225 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 ; Temperature Concentration of sodium acetate Solubility ͑2͒ Acetic acid, sodium salt 19W.V. Bhagwat and S.S. Doosaj, ͑sodium acetate͒;CH O Na; J. Indian Chem. Soc. 10,477 / / −3 2 / −3 2 3 2 t °C c2 mol dm 10 c1 mol dm ͓127-09-3͔ ͑1933͒. ͑3͒ Water; H O; ͓7732-18-5͔ 26.4 0.0100 0.0247 2 0.0201 0.0338 Variables: Prepared by: 0.0502 0.0613 Concentration of sodium acetate A. Goto, R. Goto, and H. t/ °C=30 Miyamoto Auxiliary Information Solubility of salicylic acid in water–sodium acetate mixtures Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 37 for the Concentration salicylic acid–sodium formate–water system. a Temperature of sodium acetate Solubility

Source and Purity of Materials: / −3 2 / −3 c2 mol dm 10 c1 mol dm The detail is given in the compilation of Ref. 37 for the salicylic acid– / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ t °C 2 gdm compiler 1 gdm compiler sodium formate–water system. 30 0.0000 0.000 0 2.743 0.019 86 Estimated Errors: 2.3547 0.028 704 4.828 0.034 95 Solubility: nothing speciﬁed. 3.5322 0.043 508 6.026 0.043 63 Temperature: precision Ϯ0.1 °C. 7.0643 0.086 114 9.122 0.066 04 10.4281 0.127 119 11.73 0.084 92 19.9087 0.242 687 13.99 0.112 4 Components: Original Measurements: 36.4989 0.444 922 31.06 0.224 9 26 ͑1͒ Benzoic acid, 2-hydroxy- J.C. Philip and F.B. Garner, J. 43.7986 0.533 905 36.22 0.262 2 ͑ o-hydroxybenzoic acid; salicylic Chem. Soc. Trans. 95, 1466 72.9977 0.889 843 57.25 0.414 3 acid͒;CH O ; ͓69-72-7͔ ͑1909͒. 7 6 3 109.4966 1.334 764 77.43 0.560 6 ͑2͒ Acetic acid, sodium salt ͑ ͒ 218.9932 2.669 529 147.20 1.066 sodium acetate ;C2H3O2Na; ͓ ͔ 127-09-3 a ␥ ␥ ͑ ͒ ͓ ͔ In the original data, the values 1 and 2 were given as grams per liter of 3 Water; H2O; 7732-18-5 solution. Variables: Prepared by: Auxiliary Information Concentration of sodium acetate A. Goto, R. Goto, and H. t/ °C=25 Miyamoto Methods/Apparatus/Procedure: No information was given. Solubility of salicylic acid in water–sodium acetate mixtures Source and Purity of Materials: Temperature Concentration of sodium acetate Solubility No information was given.

/ 2 / −3 2 / −3 Estimated Errors t °C 10 c2 mol dm 10 c1 mol dm Nothing speciﬁed. 25 1.23 2.61 3.06 4.29 6.13 6.92 12.28 12.17

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Solubility of salicylic acid in water–sodium propionate mixtures Components: Original Measurements: ͑ ͒ 30 1 Benzoic acid 2-hydroxy- E. Larsson, Z. Phys. Chem. Concentration of ͑ ͑ ͒ o-hydroxybenzoic acid; salicylic 127, 233 1927 . Temperature sodium propionate Solubilitya ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 ͑ ͒ 2 / −3 2 / −3 2 Acetic acid, sodium salt 10 c2 mol dm 10 c1 mol dm ͑ ͒ / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ sodium acetate ;C2H3O2Na; t °C 2 gdm compiler 1 gdm compiler ͓127-09-3͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 27.8 0.000 0.000 2.479 1.795 2.000 2.082 4.957 3.589 Variables: Prepared by: 7.810 8.130 12.795 9.264 Concentration of sodium acetate E. Königsberger and L.-C. 9.549 9.940 14.954 10.827 t/ °C=25 Königsberger 17.167 17.890 24.391 17.659 28.638 29.830 37.506 27.155 Solubility of salicylic acid in water–sodium acetate mixtures 42.982 44.740 52.461 37.892 85.963 89.480 101.24 73.301 Temperature Concentration of sodium acetate Solubility a ␥ ␥ Both 1 and 2 values were given by H. Stephen and T. Stephen, Solubili- / / −3 2 / −3 t °C c2 mol dm 10 c1 mol dm ties of Inorganic and Organic Compounds ͑Pergamon, Oxford, 1979͒,Vol. 2, Pt. 1, p. 205. In the original paper, both c and c values were given as 25 0 1.601 1 2 0.0500 6.00 “Normality” units. 0.1000 10.20 Auxiliary Information

Methods/Apparatus/Procedure: Auxiliary Information No information was given. Methods/Apparatus/Procedure: Source and Purity of Materials: The experimental detail is given in the compilation of Ref. 30 for the salicylic acid–sodium formate–water system. No information was given.

Source and Purity of Materials: Estimated Errors: Salicylic acid was from Kahlbaum. Nothing speciﬁed.

Estimated Errors: Solubility: precision Ͻ1%. Components: Original Measurements: Temperature: precision Ϯ0.1 K. ͑1͒ Benzoic acid, 2-hydroxy- 26J.C. Philip and F.B. Garner, J. ͑o-hydroxybenzoic acid; salicylic Chem. Soc. Trans. 95, 1466 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1909 . ͑ ͒ Components: Original Measurements: 2 Butanoic acid, sodium salt ͑ ͒ ͑1͒ Benzoic acid, 2-hydroxy- 32W.V. Bhagwat, J. Indian Chem. sodium butylate ;C4H7O2Na; ͓ ͔ ͑o-hydroxybenzoic acid; salicylic Soc. 16, 235 ͑1939͒. 156-54-7 ͑ ͒ ͓ ͔ ͒ ͓ ͔ 3 Water H2O; 7732-18-5 acid ;C7H6O3; 69-72-7 ͑ ͒ 2 Propionic acid, sodium salt Variables: Prepared by: ͑ ͒ sodium propionate ;C3H5O2Na; ͓ ͔ Concentration of sodium butylate A. Goto, R. Goto, and H. 137-40-6 / ͑ ͒ ͓ ͔ t °C=25 Miyamoto 3 Water; H2O; 7732-18-5

Variables: Prepared by: Solubility of salicylic acid in water–sodium butylate mixtures Concentration of sodium A. Goto and H. Miyamoto propionate Temperature Concentration of sodium butylate Solubility t/ °C=27.8 / 2 / −3 2 / −3 t °C 10 c2 mol dm 10 c1 mol dm

25 1.03 2.50 2.06 3.48 5.13 6.43

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Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 2-hydroxy- 26J.C. Philip and F.B. Garner, J. The experimental detail is given in the compilation of Ref. 26 for the ͑o-hydroxybenzoic acid; salicylic Chem. Soc. Trans. 95, 1466 ͒ ͓ ͔ ͑ ͒ salicylic acid–sodium formate–water system. acid ;C7H6O3; 69-72-7 1909 . ͑2͒ 1,4-Butanedioic acid, Source and Purity of Materials: disodium salt ͑disodium ͒ The detail is given in the compilation of Ref. 26 for the salicylic acid– succinate ;C4H4O4Na2; sodium formate–water system. ͓150-90-3͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Estimated Errors: Solubility: nothing speciﬁed. Variables: Prepared by: Temperature: precision Ϯ0.1 °C. Concentration of disodium A. Goto, R. Goto, and H. succinate Miyamoto t/ °C=25 Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 18S.S. Doosaj and W.V. Bhagwat, Solubility of salicylic acid in water–disodium succinate mixtures ͑o-hydroxybenzoic acid; salicylic J. Indian Chem. Soc. 10,225 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 ; Temperature Concentration of disodium succinate Solubility ͑2͒ 1,2,3-Propane tricarboxylic 19W.V. Bhagwat and S.S. Doosaj, / 2 / −3 2 / −3 acid, 2-hydroxy-, trisodium salt, J. Indian Chem. Soc. 10,477 t °C 10 c2 mol dm 10 c1 mol dm dihydrate; ͑sodium citrate͒; ͑1933͒. ͓ ͔ 25 0.73 2.15 C6H5O7Na3 ·2H2O; 6132-04-3 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 1.81 3.14 3.61 4.75 Variables: Prepared by: 7.25 7.84 Concentration of sodium citrate A. Goto, R. Goto, and H. t/ °C=30 Miyamoto Auxiliary Information

Solubility of salicylic acid in water–sodium citrate mixtures Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 26 for the Temperature Concentration of sodium citrate Solubilitya salicylic acid–sodium formate–water system.

/ −3 2 / −3 c2 mol dm 10 c1 mol dm Source and Purity of Materials: / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ t °C 2 gdm compiler 1 gdm compiler The detail is given in the compilation of Ref. 26 for the salicylic acid– sodium formate–water system. 30 0.0000 0.000 0 2.743 0.019 86 5.3701 0.018 26 7.875 0.057 01 Estimated Errors: 7.924 0.026 94 10.25 0.074 28 Solubility: nothing speciﬁed. 15.1313 0.051 45 15.92 0.115 3 Temperature: precision Ϯ0.1 °C. 57.7459 0.094 34 24.94 0.180 6 33.2951 0.113 21 29.73 0.215 2 55.4918 0.188 68 43.17 0.312 5 Components: Original Measurements: 83.2377 0.283 02 57.15 0.413 8 ͑1͒ Benzoic acid, 2-hydroxy- 26J.C. Philip and F.B. Garner, J. 110.9836 0.377 37 71.91 0.520 6 ͑o-hydroxybenzoic acid; salicylic Chem. Soc. Trans. 95, 1466 ͒ ͓ ͔ ͑ ͒ 166.4754 0.566 05 90.78 0.675 2 acid ;C7H6O3; 69-72-7 1909 . ͑2͒ Acetic acid, monochloro-, a ␥ ␥ ͑ In the original data, the values 1 and 2 were given as grams per liter of sodium salt sodium ͒ solution. chloroacetate ;C2H2ClO2Na; ͓3926-62-3͔ ͑ ͒ ͓ ͔ Auxiliary Information 3 Water; H2O; 7732-18-5

Methods/Apparatus/Procedure: Variables: Prepared by: No information was given. Concentration of sodium A. Goto, R. Goto, and H. chloroacetate. Miyamoto Source and Purity of Materials: t/ °C=25 No information was given.

Estimated Errors: Nothing speciﬁed.

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Solubility of salicylic acid in water–sodium chloroacetate mixtures Components: Original Measurements: 32 Temperature Concentration of sodium chloroacetate Solubility ͑1͒ Benzoic acid, 2-hydroxy- W.V. Bhagwat, J. Indian Chem. ͑o-hydroxybenzoic acid; salicylic Soc. 16,235͑1939͒. / 2 / −3 2 / −3 ͒ ͓ ͔ t °C 10 c2 mol dm 10 c1 mol dm acid ;C7H6O3; 69-72-7 ͑2͒ Acetic acid, monochloro-, 25 0.00 1.64 sodium salt ͑chloroacetic acid, 1.18 2.05 sodium salt; sodium ͒ 2.94 2.59 chloroacetate ;C2H2ClO2Na; 5.87 3.36 ͓3926-62-3͔ ͑ ͒ ͓ ͔ 11.76 4.47 3 Water; H2O; 7732-18-5 Variables: Prepared by: Auxiliary Information Concentration of sodium A. Goto and H. Miyamoto chloroacetate Methods/Apparatus/Procedure: t/ °C=25 and 28.2 The experimental detail is given in the compilation of Ref. 26 for the salicylic acid–sodium formate–water system. Solubility of salicylic acid in water–sodium chloroacetate mixtures Source and Purity of Materials: The detail is given in the compilation of Ref. 26 for the salicylic acid– Concentration of sodium formate–water system. Temperature sodium chloroacetatea Solubilitya

2 / −3 2 / −3 Estimated Errors: 10 c2 mol dm 10 c1 mol dm / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ Solubility: nothing speciﬁed. t °C 2 gdm compiler 1 gdm compiler Temperature: precision Ϯ0.1 °C. 25 0.0 0.000 2.581 1.896 1.538 1.320 3.478 2.518 2.994 2.570 3.930 2.845 Components: Original Measurements: 4.413 3.788 4.471 3.237 ͑ ͒ 30 1 Benzoic acid 2-hydroxy- E. Larsson, Z. Phys. Chem. 5.735 4.923 4.787 3.466 ͑o-hydroxybenzoic acid; salicylic 127, 233 ͑1927͒. 7.013 6.020 5.193 3.760 acid͒;CH O ; ͓69-72-7͔ 7 6 3 9.399 8.068 5.782 4.186 ͑2͒ Sodium chloroethanoate; ͑sodium chloroacetate͒; 12.605 10.830 6.369 4.611 ͓ ͔ 17.207 14.770 7.384 5.346 C2H2ClO2Na; 3926-62-3 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 31.548 27.080 10.055 7.290 63.096 54.160 13.550 9.810 Variables: Prepared by: 28.2 0.00 0.000 2.461 1.782 Concentration of sodium E. Königsberger and L.-C. 1.538 1.320 3.251 2.354 chloroacetate Königsberger 4.413 3.788 4.290 3.106 t/ °C=25 10.508 9.020 5.780 4.185 22.018 18.050 7.836 5.673 Solubility of salicylic acid in water–sodium chloroacetate mixtures 63.096 54.160 10.637 7.701

a ␥ ␥ Concentration of sodium Both 1 and 2 values were described by H. Stephen and T. Stephen, Temperature chloroacetate Solubility Solubilities of Inorganic and Organic Compounds ͑Pergamon, Oxford, ͒ 1979 , Vol. 2, Pt. 1, p. 194. In the original paper, both c1 and c2 values were t/ °C c /mol dm−3 102c /mol dm−3 2 1 given as “Normality” units. 25 0 1.601 Auxiliary Information 0.0500 3.00 0.1000 3.86 Methods/Apparatus/Procedure: No information was given. Auxiliary Information Source and Purity of Materials: Methods/Apparatus/Procedure: No information was given. The experimental detail is given in the compilation of Ref. 30 for the Estimated Errors: salicylic acid–sodium formate–water system. Nothing speciﬁed. Source and Purity of Materials: Salicylic acid was from Kahlbaum.

Estimated Errors: Solubility: precision Ͻ1%. Temperature: precision Ϯ0.1 K.

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Solubility of salicylic acid in water–sodium benzoate mixtures Components: Original Measurements: 32 ͑1͒ Benzoic acid, 2-hydroxy- W.V. Bhagwat, J. Indian Chem. Concentration of ͑o-hydroxybenzoic acid; salicylic Soc. 16, 235 ͑1939͒. Temperature sodium benzoate Solubilitya ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 ͑ ͒ / −3 2 / −3 2 Acetic acid, trichloro-, c2 mol dm 10 c1 mol dm ͑ / / −3 ͑ ͒ / −3 ͑ ͒ sodium salt trichloroacetic acid, t °C w2 gdm compiler w1 gdm compiler sodium salt; sodium ͒ 25 0.0 0.0 1.667 0.012 07 trichloroacetate ;C2Cl3O2Na; ͓650-51-1͔ 1.7306 0.012 009 2.427 0.017 57 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 3.4612 0.024 019 3.393 0.024 57 6.9224 0.048 037 3.829 0.027 72 Variables: Prepared by: 17.3061 0.120 093 4.171 0.030 20 Concentration of sodium A. Goto and H. Miyamoto 34.6121 0.240 186 4.189 0.030 33 trichloroacetate 57.6869 0.400 311 4.436 0.032 12 t/ °C=30.5 86.5303 0.600 466 4.285 0.031 02 115.3737 0.800 621 4.513 0.032 67 Solubility of salicylic acid in water–sodium trichloroacetate mixtures 173.0606 1.200 931 5.460 0.039 53

a ␥ ␥ Concentration of In the original data, the values 1 and 2 were given as g/l of solution. Temperature sodium trichloroacetatea Solubilitya Auxiliary Information 2 / −3 2 / −3 10 c2 mol dm 10 c1 mol dm / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ t °C 2 gdm compiler 1 gdm compiler Methods/Apparatus/Procedure: No information was given. 30.5 0.000 0.000 2.935 2.125 0.908 0.490b 3.025 2.190 Source and Purity of Materials: 3.326 1.794 3.094 2.240 No information was given. 9.978 5.382 3.345 2.422 Estimated Errors: a ␥ ␥ Nothing speciﬁed. Both 1 and 2 values were described by H. Stephen and T. Stephen, Solubilities of Inorganic and Organic Compounds ͑Pergamon, Oxford, ͒ 1979 , Vol. 2, Pt. 1. In the original paper, both c1 and c2 values were given by “Normality” units. Components: Original Measurements: ͑ ͒ 33 bThe value “0.4900” in the original paper should be “0.004 90”. 1 Benzoic acid, 2-hydroxy- P.A. Ongley, J. Chem. Soc. ͑o-hydroxybenzoic acid; salicylic 1954, 3634. ͒ ͓ ͔ Auxiliary Information acid ;C7H6O3; 69-72-7 ͑ ͒ 2 Sodium benzoate; C7H5O2Na; Methods/Apparatus/Procedure: ͓532-32-1͔ ͑ ͒ ͓ ͔ No information was given. 3 Water; H2O; 7732-18-5

Source and Purity of Materials: Variables: Prepared by: No information was given. t/ °C=25 A. Goto, R. Goto, and H. Miyamoto Estimated Errors: Nothing speciﬁed. Solubility of salicylic acid in water–sodium benzoate mixtures

Concentration of sodium Components: Original Measurements: Temperature benzoate Solubility ͑1͒ Benzoic acid, 2-hydroxy- 18S.S. Doosaj and W.V. Bhagwat, ͑ / / −3 a 2 / −3 ͑ ͒ o-hydroxybenzoic acid; salicylic J. Indian Chem. Soc. 10,225 t °C c2 mol dm pS 10 c1 mol dm compiler ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 ; ͑2͒ Benzoic acid, sodium salt 19W.V. Bhagwat and S.S. Doosaj, 25 0 1.793 1.611 ͑ ͒ sodium benzoate ;C7H5O2Na; J. Indian Chem. Soc. 10,477 1 1.413 3.864 ͓532-32-1͔ ͑1933͒. ͑ ͒ ͓ ͔ a 3 Water; H2O; 7732-18-5 pS is the negative logarithm of the concentration in the saturated solutions in moles per liter. Variables: Prepared by: Concentration of sodium A. Goto and H. Miyamoto benzoate t/ °C=25

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Auxiliary Information Solubility of salicylic acid in water–sodium salicylate mixtures at 20.1 °C

Methods/Apparatus/Procedure: Densitya Composition of saturated solutions Solubilities were measured by rotating tubes of solvent and solute for at ␳/ −3 / −3 / −3 / −3 b least 8 h at 25 °C. Preliminary experiments showed that saturation was gcm c1 mol dm c2 mol dm c3 mol dm Solid phase reached in 2 h. The solutions were concentrated, if necessary, and were titrated with standard alkali solution, bromothymol blue-neutral red being 1.259 0.083 4.20 32.0 B+C * used as mixed indicator. 1.259 0.048 4.18 32.4 C 1.259 0.040 4.18 32.5 C Source and Purity of Materials: 1.258* 0.021 4.12 32.6 C The acid was either of AnalaR standard or recrystallized before use. No 1.257 0 4.18 32.7 C information of the purity of sodium salts was reported. 1.257 0 4.15 32.4 C

Estimated Errors: a The asterisks refer to values interpolated between measured densities. Nothing speciﬁed. bA=salicylic acid; B=salicylic acid+sodium salicylate; C=sodium salicylate.

Components: Original Measurements: Auxiliary Information ͑1͒ Benzoic acid, 2-hydroxy- 22C. Hoitsema, Z. Phys. Chem. ͑o-hydroxybenzoic acid; salicylic 27,312͑1898͒ Methods/Apparatus/Procedure: ͒ ͓ ͔ Suspensions were shaken ͑time not specified͒ and phases were separated acid ;C7H6O3; 69-72-7 ͑2͒ Sodium 2-hydroxybenzoate either by gravity or by filtration at saturation temperature. The solid ͑sodium salicylate͒;CH O Na; phases were identified by optical microscopy. The clear saturated solutions 7 5 3 ͑ ͓54-21-7͔ were weighed occasionally densities were measured with a small ͑ ͒ ͓ ͔ pycnometer͒ and their acid contents were determined volumetrically with 3 Water; H2O; 7732-18-5 KOH solution and a trace of phenolphthalein as indicator. Water of the Variables: Prepared by: resulting solutions was evaporated in a platinum dish and the dry residue Composition E. Königsberger and L.-C. was weighed. t/ °C=20.1 Königsberger Source and Purity of Materials: “Chemically pure” salicylic acid and sodium salicylate ͑source not given͒ Solubility of salicylic acid in water–sodium salicylate mixtures at 20.1 °C were recrystallized.

Densitya Composition of saturated solutions Estimated Errors: Not stated. ␳/ −3 / −3 / −3 / −3 b gcm c1 mol dm c2 mol dm c3 mol dm Solid phase

1.002 0.0132 0 55.6 A 1.003* 0.0117 0.006 55.5 A Components: Original Measurements: 32 1.003* 0.0112 0.175 55.5 A ͑1͒ Benzoic acid, 2-hydroxy- W.V. Bhagwat, J. Indian Chem. ͑ ͑ ͒ 1.007* 0.0116 0.068 55.2 A o-hydroxybenzoic acid; salicylic Soc. 16,235 1939 . acid͒;CH O ; ͓69-72-7͔ 1.009* 0.0124 0.113 54.8 A 7 6 3 ͑ ͒ * 2 Benzoic acid, 4-amino, 1.011 0.0130 0.148 54.8 A ͑ * sodium salt sodium 1.013 0.0135 0.175 54.6 A aminobenzoate͒;CH NO Na; * 7 6 2 1.016 0.0143 0.226 54.3 A ͓555-06-6͔ 1.018* 0.0148 0.257 54.2 A ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 1.023 0.018 0.335 53.8 A 1.024* 0.0164 0.344 53.7 A Variables: Prepared by: 1.028* 0.0177 0.406 53.4 A Concentration of sodium A. Goto and H. Miyamoto 1.029* 0.186 0.422 53.25 A aminobenzoate t/ °C=28.3 and 29.1 1.034* 0.0203 0.500 52.9 A 1.047* 0.0242 0.682 51.9 A 1.050 0.024 0.72 51.9 A Solubility of salicylic acid in water–sodium aminobenzoate mixtures 1.062 0.0312 0.94 50.4 A 1.098* 0.0529 1.49 47.3 A Concentration of a a 1.112 0.062 1.70 46.3 A Temperature sodium aminobenzoate Solubility * 1.117 0.0700 1.78 45.3 A 2 / −3 2 / −3 10 c2 mol dm 10 c1 mol dm 1.137 0.095 2.11 43.7 A+B / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ t °C 2 gdm compiler 1 gdm compiler 1.144 0.091 2.19 43.4 B 1.148* 0.090 2.27 42.9 B 28.3 0.000 0.000 2.461 1.782 1.155 0.087 2.40 42.3 B 1.418 0.0891 3.479 2.518 1.190 0.088 2.95 40.8 B 1.734 1.090 3.748 2.714 1.215 0.086 3.41 36.7 B 2.600 1.634 4.449 3.221 1.226 0.087 3.55 36.1 B 5.200 3.268 4.425 3.204 1.239* 0.085 3.80 34.4 B 7.800 4.902 3.884 2.812 1.263 0.081 4.23 30.0 B+C 15.600 9.804 3.974 2.877

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Solubility of salicylic acid in water–sodium aminobenzoate mixtures Auxiliary Information

Concentration of Methods/Apparatus/Procedure: Temperature sodium aminobenzoatea Solubilitya The concentration of salicylic acid was determined by titration of sodium hydroxide in an atmosphere free from carbon dioxide, using phenol red as 2 / −3 2 / −3 10 c2 mol dm 10 c1 mol dm indicator ͓M. Kilpatrick, Jr., and E.F. Chase, J. Am. Chem. Soc. 53, 1732 / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ t °C 2 gdm compiler 1 gdm compiler ͑1931͒; E.F. Chase and M. Kilpatrick, Jr., J. Am. Chem. Soc. 53, 2589 ͑1931͒; A. Osol and M. Kilpatrick, Jr., J. Am. Chem. Soc. 55,4430 29.1 0.000 0.000 2.551 1.847 ͑1933͔͒. 1.734 1.090 3.794 2.747 2.600 1.634 4.716 3.433 Source and Purity of Materials: 5.200 3.268 4.380 3.171 Salicylic acid was purified by recrystallization. The melting point was 7.800 4.902 3.974 2.877 159 °C. 15.600 9.804 4.065 2.943 Estimated Errors: a ␥ ␥ Nothing specified. The values 1 and 2 are given by H. Stephen and T. Stephen, Solubilities of Inorganic and Organic Compounds ͑Pergamon, Oxford, 1979͒,Vol.2,Pt. 1, p. 235. The “Normality” was used in the original paper. Components: Original Measurements: Auxiliary Information ͑1͒ Benzoic acid, 2-hydroxy- 35A. Osol and M. Kilpatrick, J. ͑o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 55,4440 Methods/Apparatus/Procedure: ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 . No information was given. ͑2͒ Benzenesulfonic acid, 4-methyl, sodium salt ͑sodium Source and Purity of Materials: ͒ toluenesulfonate ;C7H7O3SNa; No information was given. ͓657-84-1͔ ͑3͒ Water; H O; ͓7732-18-56͔ Estimated Errors: 2 Nothing specified. Variables: Prepared by: Concentration of sodium A. Goto, R. Goto, and H. toluenesulfonate Miyamoto / Components: Original Measurements: t °C=25.15 ͑1͒ Benzoic acid, 2-hydroxy- 35A. Osol and M. Kilpatrick, J. ͑ o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 55, 4440 Solubility of salicylic acid in water–sodium toluenesulfonate mixtures ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 . ͑ ͒ 2 Benzenesulfonic acid, sodium Concentration of ͑ ͒ salt sodium benzenesulfonate ; sodium ͓ ͔ C6H5O3SNa; 515-42-4 Temperature toluenesulfonate Density Solubility ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-56 t/ °C c /mol dm−3 ␳/gcm−3 102c /mol dm−3 Variables: Prepared by: 2 1 Concentration of sodium A. Goto, R. Goto, and H. 25.15 0.00 — 1.598 benzenesulfonate Miyamoto 0.20 1.014 1.677 / t °C=25.15 0.50 1.032 2.191 1.00 1.066 3.903 Solubility of salicylic acid in water–sodium benzenesulfonate mixtures Auxiliary Information Concentration of sodium Methods/Apparatus/Procedure: Temperature benzenesulfonate Density Solubility The concentration of salicylic acid was determined by titration of sodium hydroxide in an atmosphere free from carbon dioxide, using phenol red as t/ °C c /mol dm−3 ␳/gcm−3 102c /mol dm−3 2 1 indicator ͓M. Kilpatrick, Jr., and E.F. Chase, J. Am. Chem. Soc. 53, 1732 ͑ ͒ 53 25.15 0.00 — 1.598 1931 ; E.F. Chase and M. Kilpatrick, Jr., J. Am. Chem. Soc. , 2589 ͑1931͒; A. Osol and M. Kilpatrick, Jr., J. Am. Chem. Soc. 55,4430 0.10 1.005 1.447 ͑1933͔͒. 0.250 1.015 1.545 0.50 1.033 1.728 Source and Purity of Materials: 1.00 1.070 2.349 Salicylic acid was purified by recrystallization. The melting point was 159 °C.

Estimated Errors: Nothing speciﬁed.

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Solubility of salicylic acid in water–acetamide mixtures Components: Original Measurements: 35 ͑1͒ Benzoic acid, 2-hydroxy- A. Osol and M. Kilpatrick, J. Concentration of ͑o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 55, 4440 Temperature acetamide Solubility ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 . Nature of ͑ ͒ 2 2-Naphthalene-sulfonic acid, 100x2 100x1 equilibrium solid ͑ / ͑ ͒ ͑ ͒ a sodium salt sodium t °C 100w2 compiler 100w1 compiler system 2-naphthalenesulfonate͒; ͓ ͔ 0 — — 0.19 0.025 SA C10H7O3SNa; 532-02-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-56 0.4 0.10 0.225 0.029 SA 1.6 0.50 0.28 0.037 SA Variables: Prepared by: 2.0 0.62 0.26 0.034 SA Concentration of sodium A. Goto, R. Goto, and H. 6.2 2.0 0.375 0.051 SA 2-naphthalenesulfonate Miyamoto 12.85 4.325 0.53 0.076 SA t/ °C=25.15 25.9 9.77 1.30 0.210 SA 37.8 16.2 2.71 0.495 SA Solubility of salicylic acid in water–sodium 2-naphthalenesulfonate mix- 44.3 20.6 4.13 0.821 SA+Compd. tures invariant point 48.9 23.9 4.24 0.887 Compd. Concentration of sodium 52.4 26.9 4.19 1.08 Compd. Temperature 2-naphthalenesulfonate Density Solubility 64.5 40.5 7.53 2.02 AC+Compd. Invariant point t/ °C c /mol dm−3 ␳/gcm−3 102c /mol dm−3 2 1 79.3 53.9 — — AC 25.15 0.00 — 1.598 aSA=Salicylic acid; AC=acetamide. 0.10 1.005 1.543 0.2 1.010 1.983 Auxiliary Information

Methods/Apparatus/Procedure: Auxiliary Information The complete equilibrium diagram for the ternary system salicylic Methods/Apparatus/Procedure: acid–acetamide–water at 20 °C was determined. The salicylic acid was The concentration of salicylic acid was determined by titration of sodium estimated by titration and the acetamide was estimated by distillation with hydroxide in an atmosphere free from carbon dioxide, using phenol red as sodium hydroxide. indicator ͓M. Kilpatrick, Jr., and E.F. Chase, J. Am. Chem. Soc. 53, 1732 Source and Purity of Materials: ͑1931͒; E.F. Chase and M. Kilpatrick, Jr., J. Am. Chem. Soc. 53, 2589 Salicylic acid was recrystallized from water. Acetamide was distilled ͑1931͒; A. Osol and M. Kilpatrick, Jr., J. Am. Chem. Soc. 55, 4430 several times and protected from moist air. ͑1933͔͒. Estimated Errors: Source and Purity of Materials: Nothing speciﬁed. Salicylic acid was puriﬁed by recrystallization. The melting point was 159 °C.

Estimated Errors: Components: Original Measurements: Nothing speciﬁed. ͑1͒ Benzoic acid, 2-hydroxy- 39H. Nogami, T. Nagai, and K. ͑o-hydroxybenzoic acid; salicylic Ito, Chem. Pharm. Bull. 14,351 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O2; 69-72-7 1966 . ͑ ͒ ͓ ͔ 2 Urea; CH4N2O; 57-13-6 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: 3.1.1.5. Amides Concentration of urea A. Goto and R. Goto t/ °C=30 Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 21A.N. Campbell and A.J.R. Solubility of salicylic acid in water–urea mixtures ͑o-hydroxybenzoic acid; salicylic Campbell, J. Am. Chem. Soc. 62, ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 291 1940 . Temperature Concentration of urea Solubility ͑ ͒ 2 Acetamide; C2H5ON; 2 / −1 ͓60-35-5͔ 10 m1 mol kg ͑ ͒ ͓ ͔ / / −3 ͑ ͒a ͑ ͒ 3 Water; H2O; 7732-18-5 t °C c2 mol dm % obs compiler

Variables: Prepared by: 30 0 0.261 2.14 Concentration of acetamide A. Goto and H. Miyamoto 0.5 0.316 2.60 t/ °C=20 1 0.374 3.07 1.5 0.434 3.57 2 0.528 4.03

aThe compiler assumed that % should be read as “mass %.”

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Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 39 for the Suspensions were shaken in carefully cleaned ͑steamed͒ glass bottles with 3-hydroxybenzoic acid–water system in Sec. 2.1.1.2. The optical density rubber stoppers placed in an Ostwald thermostat ͑times not specified͒. of salicylic acid was determined at 232 and 296 nm. After the solid phase was settled, filtration at equilibrium temperature was performed by pressing the solution through a glass tube filled with glass Source and Purity of Materials: wool. The filtrate, the first 20 cm3 of which was discarded, was weighed ͑ ͒ Salicylic acid and urea were of the purest reagent grade. and titrated with Ba OH 2 solution using phenolphthalein as indicator. ͑ ͒ Care was taken to avoid contamination of Ba OH 2 with atmospheric Estimated Errors: CO2. Nothing specified. Source and Purity of Materials: Salicylic acid ͑Kahlbaum͒ was recrystallized repeatedly from water and then from ethanol, m.p. 156 °C. ␣-D-Glucose ͑Kahlbaum͒ was dried at 80–85 °C.

Estimated Errors: 3.1.1.6. Carbohydrates Solubility: nothing speciﬁed. Temperature: precision Ϯ0.03 K. Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 23Fr. Hoffmann and K. Langbeck, ͑o-hydroxybenzoic acid; salicylic Z. Phys. Chem. 51,385͑1905͒. Components: Original Measurements: ͒ ͓ ͔ ͑ ͒ 23 acid ;C7H6O3; 69-72-7 1 Benzoic acid, 2-hydroxy- Fr. Hoffmann and K. Langbeck, ͑2͒ ␣-D-Glucose ͑dextrose͒; ͑o-hydroxybenzoic acid; salicylic Z. Phys. Chem. 51,385͑1905͒. ͓ ͔ ͒ ͓ ͔ C6H12O6; 492-62-6 acid ;C7H6O3; 69-72-7 ͑ ͒ ͓ ͔ ͑ ͒ ͑ ͒ 3 Water; H2O; 7732-18-5 2 D-Fructose levulose ; ͓ ͔ C6H12O6; 57-48-7 Variables: Prepared by: ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Concentration of D-glucose E. Königsberger and L.-C. t/ °C=24.89 and 34.82 Königsberger Variables: Prepared by: Concentration of D-fructose E. Königsberger and L.-C. t/ °C=24.89 Königsberger Solubility of salicylic acid in water–D-glucose mixtures

Concentration Solubility Solubility of salicylic acid in water–D-fructose mixtures Temperature of D-glucose Solubilitya change Concentration Solubility 2 / −1 a 10 m1 mol kg Temperature of D-fructose Solubility change / 2 / −1 4 ͑ ͒ b t °C 10 x2 m2 mol kg 10 x1 compiler % 2 / −1 10 m1 mol kg 24.89 0 0 2.8851 1.602 100.00 / 2 / −1 4 ͑ ͒ b t °C 10 x2 m2 mol kg 10 x1 compiler % 0.036 13 0.020 06 2.8863 1.603 100.04 0.045 09 0.025 04 2.8892 1.605 100.14 24.89 0 0 2.8851 1.602 100.00 0.060 31 0.035 50 2.8915 1.607 100.22 0.036 02 0.020 00 2.8883 1.604 100.11 0.090 45 0.052 53 2.8901 1.606 100.17 0.044 84 0.025 00 2.8939 1.608 100.30 0.181 9 0.101 15 2.8983 1.612 100.43 0.059 77 0.033 16 2.8959 1.609 100.38 0.455 0 0.253 79 2.9232 1.631 101.32 0.107 4 0.059 68 2.8954 1.609 100.35 0.920 0 0.515 48 2.9536 1.655 102.37 0.181 1 0.100 67 2.9078 1.618 100.79 1.367 5 0.769 66 2.9896 1.683 103.62 0.450 9 0.251 39 2.9445 1.642 102.06 1.782 8 1.007 6 3.0149 1.705 104.49 a m ͑x /M ͒/͑ 34.82 0 0 4.1844 2.324 100.00 The molality solubility was calculated from the equation 1 = 1 3 1 ͒ 0.036 11 0.020 05 4.1847 2.325 100.01 −x1 −x2 by the compilers. b 0.045 16 0.025 08 4.1869 2.326 100.06 With respect to pure water. 0.060 17 0.033 42 4.1845 2.325 100.00 Auxiliary Information 0.089 70 0.049 84 4.1917 2.330 100.18 0.178 7 0.099 38 4.2019 2.338 100.42 Methods/Apparatus/Procedure: 0.437 1 0.244 67 4.2152 2.351 100.74 The experimental detail is given in the compilation of Ref. 23 for the 0.855 6 0.480 51 4.2627 2.388 101.88 salicylic acid–D-glucose–water system. 1.239 8 0.696 95 4.3103 2.424 103.01 Source and Purity of Materials: 1.732 2 0.978 63 4.3601 2.464 104.20 Salicylic acid ͑Kahlbaum͒ was recrystallized repeatedly from water and a ͑ / ͒/͑ then from ethanol, m.p. 156 °C. D-Fructose ͑Kahlbaum͒ was dried at The molality solubility was calculated from the equation m1 = x1 M3 1 ͒ 80–85 °C. −x1 −x2 by the compilers. bWith respect to pure water.

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Estimated Errors: aThe molality solubility of salicylic acid was calculated from the equation ͑ / ͒/͑ ͒ Solubility: nothing speciﬁed. m1 = x1 M3 1−x1 −x2 by the compilers. Temperature: precision Ϯ0.03 K. bWith respect to pure water.

Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 2-hydroxy- 23Fr. Hoffmann and K. Langbeck, The experimental detail is given in the compilation of Ref. 23 for the ͑o-hydroxybenzoic acid; salicylic Z. Phys. Chem. 51,385͑1905͒. ͒ ͓ ͔ salicylic acid–D-glucose–water system. acid ;C7H6O3; 69-72-7 ͑ ͒ ͑ ͒ 2 Sucrose saccharose ; Source and Purity of Materials: C H O ; ͓57-50-1͔ 12 22 11 Salicylic acid ͑Kahlbaum͒ was recrystallized repeatedly from water and ͑3͒ Water; H O; ͓7732-18-5͔ 2 then from ethanol, m.p. 156 °C. Sucrose was “Feinste Indisch-Rafﬁnade.” Variables: Prepared by: Estimated Errors: Concentration of sucrose E. Königsberger and L.-C. Temperature: precision Ϯ0.03 K. t/ °C=24.89 and 34.82 Königsberger Solubility: not stated.

Solubility of salicylic acid in water–sucrose mixtures

Concentration Solubility Temperature of sucrose Solubilitya change

2 / −1 10 m1 mol kg 3.1.1.7. Aromatic compounds / 2 / −1 4 ͑ ͒ b t °C 10 x2 m2 mol kg 10 x1 compiler %

24.89 0 0 2.8851 1.602 100.00 Components: Original Measurements: 0.036 25 0.020 130 2.9023 1.612 100.59 ͑1͒ Benzoic acid, 2-hydroxy- 71E. Cohen and W.D.J. van 0.045 20 0.025 106 2.9047 1.614 100.68 ͑o-hydroxybenzoic acid, salicylic Dobbenburgh, Z. Phys. Chem. ͒ ͓ ͔ ͑ ͒ 0.062 70 0.033 476 2.9107 1.617 100.90 acid ;C7H6O3; 59-72-7 118,37 1925 . ͑ ͒ ͓ ͔ 0.091 00 0.050 564 2.9625 1.626 101.43 2 Water; H2O; 7732-18-5 ͑ ͒ ͓ ͔ 0.183 81 0.102 22 2.9637 1.649 102.72 3 Benzene; C6H6; 71-43-2 0.460 60 0.257 12 3.0730 1.714 106.50 Variables: Prepared by: 0.916 01 0.513 09 3.2391 1.815 112.27 Composition E. Königsberger and L.-C. 1.150 8 0.646 30 3.3264 1.869 115.28 t/ °C=30.50 Königsberger 1.340 4 0.754 18 3.4142 1.922 118.34 1.940 3 1.098 50 3.6326 2.057 125.90 34.82 0 0 4.1844 2.324 100.0 0.036 06 0.020 02 4.2060 2.337 100.52 0.045 10 0.025 05 4.2028 2.335 100.44 0.060 41 0.033 56 4.2152 2.342 100.74 0.090 65 0.050 37 4.2383 2.356 101.29 0.181 24 0.100 80 4.2870 2.385 102.45 0.455 57 0.254 09 4.4591 2.488 106.57 0.880 84 0.493 40 4.5967 2.632 112.24 1.350 1 0.759 87 4.9438 2.783 118.15 1.942 4 1.099 90 5.2365 2.966 125.14

Solubility of salicylic acid in water–benzene mixtures and in benzene

Temperature Salicylic acid–water–benzene Salicylic acid–benzene

a a 100w1 100w1 100w1 100w1 100w1 100w1 / 5 ͑ ͒ ͑ ͒ ͑ ͒ ͑ ͒ ͑ ͒ ͑ ͒ t °C 10 w2 ﬁrst analysis second analysis Av. ﬁrst analysis second analysis Av.

30.50 4 1.015 1.015 1.015 1.003 1.009 1.006 14.7 1.049 1.050 1.050 1.003 1.001 1.002 37.4 1.094 1.097 1.096 1.007 — ͑1.007͒ 68.2 1.188 1.193 1.091 1.013 1.014 1.014 104.2 1.308 1.310 1.309 1.015 1.011 1.013 147.8 1.347 1.349 1.348 1.011 1.014 1.013 217.1 1.353 1.349 1.351 1.011 1.020 1.016 313 1.351 1.352 1.352 1.021 1.020 1.021 excess 1.354 1.359 1.357

aThe average was calculated by the compiler.

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Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: In parallel experiments, dry benzene and benzene containing a known Dry organic solvent and solvent containing a known amount of water amount of water were added to dry salicylic acid contained in two were added to dry salicylic acid contained in carefully dried, weighed carefully dried, weighed bottles. These were shaken in an Ostwald bottles. The dry solvent was manipulated in a closed system to avoid thermostat for 5–6 h at 30.50 °C. After settling of the solid phase, two contact with moist air. The bottles were shaken in an Ostwald thermostat samples of the supernatant solution were taken using a glass tube at 30.50 °C. After settling of the solid phase, two samples of the containing some cotton wool. The samples were weighed, the benzene supernatant solution were taken using a glass tube containing some cotton was evaporated by a dry air stream, and the dry residues were weighed wool. The samples were weighed, the solvent was evaporated by a dry air again. stream and the dry residues were weighed again. Equilibrium was attained from under- and supersaturation. The latter was obtained by heating the Source and Purity of Materials: solution until almost all of the solid phase was dissolved, then the Salicylic acid ͑Kahlbaum͒ was recrystallized from dry ether, ground, and suspension was shaken at 30.50 °C for 3–5 h. kept in a desiccator over P4O10. Water was distilled from a tin-coated apparatus. Thiophene-free benzene was kept with P4O10 for several days, Source and Purity of Materials: then distilled slowly. Salicylic acid ͑Kahlbaum͒ was recrystallized from dry ether, ground, and

kept in a desiccator over P4O10. Water was distilled from a tin-coated Estimated Errors: apparatus. Thiophene-free benzene was kept with P4O10 for several days, Temperature: uncertainty Ϯ0.02 K. then distilled slowly. Mass concentration: uncertainty Ϯ0.1 mg. Estimated Errors: Not stated. Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 71E. Cohen and W.D.J. van ͑o-hydroxybenzoic acid; salicylic Dobbenburgh, Z. Phys. Chem. Components: Original Measurements: ͒ ͓ ͔ ͑ ͒ ͑ ͒ 73 acid ;C7H6O3; 59-72-7 118,37 1925 . 1 Benzoic acid, 2-hydroxy- I.L. Krupatkin, Zh. Obsh. ͑ ͒ ͓ ͔ ͑ ͑ ͓͒ 2 Water; H2O; 7732-18-5 o-hydroxybenzoic acid; salicylic Khim. 26,3240 1956 J. Gen. ͑ ͒ ͓ ͔ ͒ ͓ ͔ ͑ ͒ 3 Benzene; C6H6; 71-43-2 acid ;C7H6O3; 69-72-7 Chem. USSR Engl. Transl. 26, ͑2͒ Benzine ͑petroleum ether͒ 3609 ͑1956͔͒. ͑ ͒ ͓ ͔ Variables: Prepared by: 3 Water; H2O; 7732-18-5 Concentration of benzene E. Königsberger and L.-C. t/ °C=30.50 Königsberger Variables: Prepared by: Composition A. Goto and H. Miyamoto

Solubility of salicylic acid in water–benzene mixtures

Temperature Concentration of benzene Solubility

c Shaking 100w1 / 5 a b ͑ ͒ t °C time/h 10 w2 100w1 100w1 compiler

30.50 4 0 1.02 1.00 1.01 4 0 1.01 — ͑1.01͒ 3 0 — 1.02 ͑1.02͒ 3 66 1.16 1.17 1.17 4 71 1.19 1.18 1.18

aAn undersaturation method was used to determine the solubility. bA supersaturation method was used to determine the solubility. c a b The mean value was calculated from the w1 and w1 values.

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Polytherms of salicylic acid–benzine–water system

Crystallization Composition of saturated solutions Temperature Stratiﬁcation temperature

Salicylic Benzine Water

Acid 100w2 100w3 Two-phase Three-phase ͑ ͒ ͑ ͒ / / / Section number 100w1 compiler compiler t °C t °C t °C

1. 49.00 2.55 48.45 — 90.0 — Benzine 5%, 50.00 2.50 47.50 — 100.0 — Water 95% 2. 6.00 18.80 75.20 — — 89.0 Benzine 20%, 7.00 18.60 74.40 — — 96.0 Water 80% 10.00 18.00 72.00 102.00 — 98.0 20.00 16.00 64.00 101.00 — 102.0 30.00 14.00 56.00 104.5 — 103.0 40.00 12.00 48.00 105.0 — 101.0 45.00 11.00 44.00 — — 99.0 55.00 9.00 36.00 — — 90.0 60.00 8.00 32.00 106.0 — 81.0 69.00 6.20 24.80 — 120.0 — 70.00 6.00 24.00 110.0 105.0 — 71.00 5.80 23.20 — 78.0 — 80.00 4.00 16.00 119.00 — — 90.00 2.00 8.00 134.00 — — 100.00 0.00 0.00 155.00 — — 3. 7.00 37.20 55.80 — — 92.00 Benzine 40% 10.00 36.00 54.00 103.0 — 100.0 Water 60% 20.00 32.00 48.00 104.00 — 103.0 30.00 28.00 42.00 105.0 — 104.0 40.00 24.00 36.00 106.0 — 100.0 50.00 20.00 30.00 107.0 — 90.0 60.00 16.00 24.00 108.0 — — 70.00 12.00 18.00 112.0 125.0 — 72.00 11.20 16.80 — 102.0 — 73.00 10.80 16.20 — 80.0 — 80.00 8.00 12.00 121.0 — — 90.00 4.00 6.00 147.0 — — 100.00 0.00 0.00 155.0 — — 4 6.00 56.40 37.60 — — 85.0 Benzine 60% 9.00 54.60 36.40 103.0 — 100.0 Water 40% 18.00 49.20 32.80 104.0 — 102.5 23.00 46.20 30.80 104.5 — 103.0 33.00 40.20 26.80 105.0 — 100.0 37.00 37.80 25.20 105.0 — 98.0 41.00 35.40 23.60 106.0 — 89.0 50.00 30.00 20.00 108.0 — 70.0 60.00 24.00 16.00 110.0 — — 69.00 18.60 12.40 — 136.0 — 70.00 18.00 12.00 118.0 113.0 — 71.00 17.40 11.60 — 91.0 — 80.00 12.00 8.00 128.0 — — 90.00 6.00 4.00 140.0 — — 100.00 0.00 0.00 155.0 — — 5 6.00 75.20 18.80 — — 90.0 Benzine 80% 7.30 74.16 18.54 — — 100.0 Water 20% 9.00 72.80 18.20 107.0 — 103.0 16.00 67.20 16.80 108.0 — 104.0 22.00 62.40 15.60 — — 100.0 23.00 61.60 15.40 109.0 — 96.0 28.00 57.60 14.40 109.5 — 87.0

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Polytherms of salicylic acid–benzine–water system

Crystallization Composition of saturated solutions Temperature Stratiﬁcation temperature

Salicylic Benzine Water

Acid 100w2 100w3 Two-phase Three-phase ͑ ͒ ͑ ͒ / / / Section number 100w1 compiler compiler t °C t °C t °C

40.00 48.00 12.00 112.0 — — 50.00 40.00 10.00 113.0 — — 60.00 32.00 8.00 115.0 — — 69.00 24.80 6.20 — 141.0 — 70.00 24.00 6.00 123.0 124.0 — 71.00 23.20 5.80 — 98.0 — 80.00 16.00 4.00 134.0 — — 90.00 8.00 2.00 146.0 — — 10.00 0.00 0.00 155.0 — — 6 48.00 49.40 2.60 — 80.0 — Benzine 95% 49.00 48.45 2.55 — 102.0 — Water 5% 50.00 47.50 2.50 — 125.0 —

Auxiliary Information Polytherm for the salicylic acid–aminobenzoic acid–water system

Methods/Apparatus/Procedure: Composition of Equilibrium between three liquid phases was studied by the visual saturated solutions Temperature polythermal method. The ternary system, salicylic acid–water–benzine, was studied by means of polythermal sections drawn through its Salicylic temperature-concentration prism. The starting substances were heated in Aminobenzoic acid sealed glass ampoules in an oil thermostat. The crystallization of the Section Water acid 100w2 100w1 Crystallization Stratiﬁcation ͑ ͒ ͑ ͒ / / mixtures was studied in these ampoules; in this connection needlelike number 100w3 compiler compiler t °C t °C crystal of salicylic acid was formed at the boundary of two liquid layers. 1. 0.00 20.00 80.00 141.0 — Source and Purity of Materials: Salicylic acid 10.03 17.99 71.98 116.0 — The melting point of C.P. grade salicylic acid used was 155 °C. The 80% 20.53 15.89 63.58 103.0 — twice-distilled water and the benzine fraction boiling in the range Aminobenzoic 31.69 13.66 54.65 98.0 — 90–120 °C were used. acid 20% 36.76 12.65 50.59 97.0 62.0 39.89 12.02 48.09 96.0 72.0 Estimated Errors: 41.30 11.74 46.96 96.0 73.0 Nothing speciﬁed. 50.18 9.96 39.86 96.0 80.0 62.53 7.49 29.98 95.5 81.0 70.78 5.84 23.38 95.5 81.0 Components: Original Measurements: 79.59 4.08 16.33 95.0 81.0 ͑1͒ Benzoic acid, 2-hydroxy- 74I.L. Krupatkin, Sbornik Statei 89.92 2.02 8.06 94.0 74.5 ͑o-hydroxybenzoic acid; salicylic po Obshchei. Khim., Akad. Nauk ͒ ͓ ͔ ͑ ͒ 94.11 1.18 4.71 90.0 65.0 acid ;C7H6O3; 69-72-7 S.S.S.R. 2, 1221 1953 . ͑2͒ Benzoic acid, 2-amino- 95.05 0.99 3.96 87.5 — ͑o-aminobenzoic acid; anthranilic 96.08 0.78 3.14 70.0 — ͒ 2. 0.00 40.00 60.00 123.5 — acid; vitamin L1 ;C7H7NO2; ͓118-92-3͔ Salicylic acid 10.13 35.95 53.92 109.0 — ͑ ͒ ͓ ͔ 60% 3 Water; H2O; 7732-18-5 23.47 30.61 45.92 99.5 — Aminobenzoic 33.52 26.59 39.89 96.00 65.0 Variables: Prepared by: acid 40% 47.53 20.99 31.48 94.0 76.0 Composition and temperature A. Goto and H. Miyamoto 60.11 15.96 23.95 93.5 78.0 71.57 11.37 17.06 93.5 78.5 77.34 9.06 13.60 93.0 77.5 89.77 4.09 6.14 91.0 69.0 95.53 1.79 2.68 83.0 — 96.04 1.58 2.38 60.0 —

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Polytherm for the salicylic acid–aminobenzoic acid–water system Solubility of salicylic acid in water–phenol mixtures

Composition of Concentration Solubility of Solid saturated solutions Temperature Temperature of phenol salicylic acid Density phasea

Salicylic 100x2 100x1 / ͑ ͒ ͑ ͒ 3␳/ −3 Aminobenzoic acid t °C 100w2 compiler 100w1 compiler 10 kg m Section Water acid 100w2 100w1 Crystallization Stratiﬁcation ͑ ͒ ͑ ͒ / / number 100w3 compiler compiler t °C t °C 25.0 — — 0.22 0.029 1.0008 S+soln. 2.42 0.47 0.28 0.037 1.0032 S+soln. 3. 0.00 60.00 40.00 117.0 — 5.05 1.01 0.40 0.055 1.0057 S+soln. Salicylic acid 9.85 54.09 36.06 105.0 — 7.51 1.54 0.53 0.074 1.0080 S+L1 +L2 40% 19.29 48.43 32.28 100.5 — 59.07 25.35 8.77 2.56 1.0640 S+L1 +L2 Aminobenzoic 29.57 42.26 28.17 97.0 — 62.66 28.87 8.96 2.81 1.0700 S+soln. acid 60% 35.09 38.95 25.96 96.5 63.0 83.00 58.00 6.32 3.01 1.0761 S+soln. 39.97 36.02 24.01 96.0 71.5 90.74 76.76 4.60 2.65 1.0785 P+S+soln. 50.85 29.49 19.66 95.5 75.5 93.10 79.01 2.49 1.44 1.0793 P+soln. 60.38 23.77 15.85 95.0 77.0 95.70 80.99 — — 1.0803 P+soln. 69.84 18.10 12.06 95.0 76.5 70.19 31.07 — — 1.0470 L1 +L2 79.72 12.17 8.11 94.0 73.0 8.43 1.73 — — 1.0070 L1 +L2 89.86 6.08 4.06 91.5 62.0 69.28 30.46 0.51 0.15 1.0500 L1 +L2 8.35 1.71 0.04 0.0056 1.0072 L +L 94.98 3.01 2.01 81.0 — 1 2 67.41 29.38 1.81 0.54 1.0529 L +L 97.00 1.80 1.20 66.0 — 1 2 8.23 1.69 0.13 0.018 1.0074 L +L 4. 0.00 80.00 20.00 133.0 — 1 2 65.79 28.48 3.12 0.93 1.0544 L +L Salicylic acid 10.33 71.74 17.93 110.0 — 1 2 8.14 1.67 0.21 0.029 1.0075 L +L 20% 20.60 63.52 15.88 103.0 — 1 2 60.80 26.29 7.56 2.23 1.0610 L1 +L2 Aminobenzoic 28.73 57.02 14.25 100.5 — acid 80% 7.66 1.57 0.46 0.064 1.0078 L1 +L2 34.85 52.12 13.03 98.5 64.5 30.0 — — 0.26 0.034 S+soln. 39.60 48.32 12.08 98.0 70.0 2.6 0.51 0.40 0.053 S+soln. 49.72 40.22 10.06 97.0 76.0 7.5 1.54 0.60 0.084 S+soln. 60.21 31.83 7.96 97.0 76.5 56.6 23.7 9.8 2.8 S+L1 +L2 70.04 23.97 5.99 96.5 76.5 8.0 1.7 0.64 0.090 S+L1 +L2 79.55 16.36 4.09 96.0 74.0 71.6 40.8 9.8 3.8 S+soln. 89.94 8.05 2.01 94.0 63.0 84.9 64.6 7.1 3.7 S+soln. 94.97 4.02 1.01 82.0 — 88.5 72.7 5.9 3.3 S+soln. 97.31 2.15 0.54 63.0 — 92.5 83.8 4.7 2.9 P+S+soln. 94.5 92.8 4.7 3.1 P+soln. 97.2 86.9 — — P+soln. Auxiliary Information 69.3 30.2 — — L1 +L2 Methods/Apparatus/Procedure: 9.1 1.9 — — L1 +L2 44.0 — — 0.46 0.060 S+soln. The experiment was performed by the polythermic method in sealed glass ampoules in an oil thermostat ͓V. F. Alekseev, J. Russ. Chem. Soc. 8, 249 7.8 1.6 1.2 0.17 S+soln. ͑1876͔͒. 47.8 18.5 13.6 3.58 L1 +L2 +S 8.9 1.9 1.4 0.20 L1 +L2 +S Source and Purity of Materials: 49.6 20.0 14.4 3.96 S+soln. Chemically pure grade salicylic acid with m.p. 155 °C and chemically 56.8 26.7 15.4 4.94 S+soln. pure grade aminobenzoic acid with m.p. 145 °C were used. 61.9 32.3 15.3 5.45 S+soln. Twice-distilled water was used. 70.9 44.9 14.3 6.17 S+soln. 87.8 76.8 8.2 4.9 S+soln. Estimated Errors: 82.8 65.3 10.1 5.43 S+soln. Nothing speciﬁed. 92.5 94.8 7.5 5.2 S+soln.

63.5 25.3 0.72 0.20 L1 +L2 10.1 2.11 0.09 0.013 L1 +L2 Components: Original Measurements: 59.0 23.3 4.3 1.2 L1 +L2 17 ͑1͒ Benzoic acid, 2-hydroxy- C.R. Bailey, J. Chem. Soc. 10.4 2.18 0.44 0.063 L1 +L2 ͑o-hydroxybenzoic acid; salicylic Trans. 126, 1951 ͑1925͒. 52.6 20.4 9.2 2.4 L1 +L2 ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 9.7 2.0 1.0 0.14 L1 +L2 ͑ ͒ ͓ ͔ 2 Phenol; C6H6O; 108-95-2 50.3 19.5 11.3 2.98 L1 +L2 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 9.6 2.0 1.2 0.17 L1 +L2 64.2 25.6 — — L1 +L2 Variables: Prepared by: 10.2 2.13 — — L1 +L2 Concentration of phenol A. Goto and H. Miyamoto t/ °C=25.0–68.8

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Solubility of salicylic acid in water–phenol mixtures Auxiliary Information

Concentration Solubility of Solid Methods/Apparatus/Procedure: Temperature of phenol salicylic acid Density phasea Both analytical and synthetic methods were used. In the analytical method, the mixtures of salicylic acid, phenol and water, were stirred in a 100x2 100x1 thermostat. After equilibrium was established, the solution was sucked off / ͑ ͒ ͑ ͒ 3␳/ −3 t °C 100w2 compiler 100w1 compiler 10 kg m through a side tube with filter into a stopper flask and weighed, transferred to a measuring flask. Phenol was estimated by the 58.0 — — 0.80 0.11 S+soln. bromide-bromate method. Salicylic acid was determined with barium 7.7 1.6 2.3 0.33 S+soln. hydroxide using p-nitrophenol as an indicator. In the synthetic method, 33.2 11.0 17.4 3.91 L1 +L2 +S varying amounts of salicylic acid were added to known mixtures of 12.7 2.83 4.3 0.65 L1 +L2 +S phenol and water and the temperatures of sudden thickening were 48.0 22.3 22.9 7.24 S+soln. determined. The work was carried out in sealed tubes. The temperature of 55.6 29.9 22.4 8.21 S+soln. the beginning of critical opalescence was also determined. 73.2 53.5 16.8 9.36 S+soln. 89.0 92.2 11.0 7.77 S+soln. Source and Purity of Materials: Commercial salicylic acid was recrystallized from water four times. 44.2 14.5 6.8 1.5 L1 +L2 Physiologically pure salicylic acid was also used. The salicylic acid was 14.5 3.22 2.4 0.36 L1 +L2 dissolved in a hot mixture of phenol and water. The solution obtained was 15.3 3.34 — — L1 +L2 55.6 19.3 — — L +L slowly cooled. After recrystallizing twice, the melting point of the product 1 2 was 158.7 °C. When allowance was made for stem distillation, the ͓— — 4.0 0.54͔ L +L 1 2 melting point was increased to 160.4 °C. The phenol crystals were ͓— — 76.0 29.2͔ L +L 1 2 purchased from British Drug Houses and were distilled twice. The melting 61.0 28.1 8.98 20.0 4.36 L +L +S 1 2 point of the product was 40.8 °C. 13.5 3.07 5.6 0.87 L1 +L2 +S 15.9 3.74 6.6 1.1 L1 +L2 Estimated Errors: 28.3 8.12 12.0 2.35 L1 +L2 Nothing specified. 19.3 4.67 6.0 0.99 L1 +L2 23.0 5.95 8.5 1.5 L1 +L2 19.3 4.62 5.0 0.81 L +L 1 2 Components: Original Measurements: 29.0 8.00 8.0 1.5 L +L 1 2 ͑1͒ Benzoic acid, 2-hydroxy- 75I.L. Krupatkin, Zh. Obsh. 18.9 4.27 — — L +L 1 2 ͑o-hydroxybenzoic acid; salicylic Khim. 25,1640͑1955͒. 52.8 17.6 — — L +L 1 2 acid͒;CH O ; ͓69-72-7͔ ͓— — 4.6 0.62͔ L +L 7 6 3 1 2 ͑2͒ 2,4,6-Trinitorophenol ͑picric ͓ ͔ — — 67.2 21.1 L1 +L2 ͒ ͓ ͔ acid ;C6H3N3O7; 88-89-1 63.0 — — 1.0 0.13 S+soln. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 11.5 2.55 5.2 0.79 S+soln. 14.2 3.32 7.6 1.2 S+soln. Variables: Prepared by:

25.2 7.32 15.8 3.13 S+L3 +L4 Composition and temperature A. Goto and H. Miyamoto 14.5 3.43 8.5 1.4 S+L3 +L4 34.2 12.0 20.6 4.94 S+soln. 87.0 90.8 13.0 9.24 S+soln Polytherms for the salicylic acid–picric acid–water system 31.8 8.48 2.9 0.53 Crit.Pt. ͑ ͒ Composition of L1 +L2 saturated solutions Temperature 43.0 13.0 1.9 0.39 L1 +L2 20.5 4.74 0.8 0.13 L1 +L2 Salicylic 23.0 5.41 — — L1 +L2 acid Picric acid 49.3 15.7 — — L +L 1 2 Section 100w1 100w2 Water Stratiﬁcation Crystallization 18.0 4.49 10.0 1.70 Crit.Pt. ͑ ͒ ͑ ͒ / / number compiler compiler 100w3 t °C t °C ͑ ͒ L1 +L2 16.0 3.87 9.0 1.5 L3 +L4 1. 60.45 4.55 35.00 58.0 22.3 6.00 12.5 2.29 L3 +L4 Salicylic acid 55.50 4.18 40.32 68.5 ͓ ͔ 93% — — 4.6 0.62 L3 +L4 46.50 3.50 50.00 74.0 ͓ ͔ Picric acid — — 68.6 22.2 L3 +L4 37.2 2.80 60.00 76.5 68.8 — — 1.3 0.17 S+soln 7% 27.36 2.06 70.58 77.0 9.6 2.1 6.0 0.90 S+soln 18.56 1.40 80.04 77.0 19.0 5.21 17.0 3.17 S+soln 8.99 0.68 90.33 74.0 38.0 16.1 27.6 7.95 S+soln 6.51 0.49 93.00 65.0 45.9 23.9 30.1 10.7 S+soln 2. 51.34 8.36 40.30 65.5 60.0 38.6 25.0 11.0 S+soln Salicylic acid 43.00 7.00 50.00 70.0 84.6 89.0 15.4 11.0 S+soln 86% 33.94 5.52 60.54 72.0 Picric acid a ͑ ͒ 25.52 4.16 70.32 72.0 S=soln salicylic acid; P=solid phenol; W=ice; L1 = low acid content 14% 17.17 2.80 80.03 71.0 layer rich in phenol; L =layer rich in water; L =͑low phenol content͒ layer 2 3 8.54 1.39 90.07 65.5 rich in acid; L4 =layer rich in acid. Metastable results are enclosed in square brackets.

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Polytherms for the salicylic acid–picric acid–water system Source and Purity of Materials: The melting point of chemically pure grade salicylic acid was 155 °C. Composition of The melting point of chemically pure grade picric acid which was saturated solutions Temperature recrystallized from ethanol was 122.5 °C. Water was distilled twice.

Salicylic Estimated Errors: acid Picric acid Nothing speciﬁed. Section 100w1 100w2 Water Stratiﬁcation Crystallization ͑ ͒ ͑ ͒ / / number compiler compiler 100w3 t °C t °C 3.1.1.8. Heterocyclic compounds 3. 48.6 11.4 40.00 64.00 Salicylic acid 40.50 9.50 50.00 69.00 81% 32.39 7.60 60.01 69.00 Components: Original Measurements: Picric acid 24.30 5.70 70.00 69.00 ͑1͒ Benzoic acid 2-hydroxy- 76W. Herz and E. Lorenz, Z. 19% 15.85 3.72 80.43 68.00 ͑o-hydroxybenzoic acid; salicylic Phys. Chem. Abt. A 140,406 ͒ ͓ ͔ ͑ ͒ 8.10 1.90 90.00 65.00 acid ;C7H6O3; 69-72-7 1929 . ͑ ͒ 4. 50.70 14.30 35.00 57.00 — 2 1,4-Diethylenedioxide ͑ ͒ Salicylic acid 1,4-dioxane ;C4H8O2; 46.53 13.13 40.34 63.00 — ͓ ͔ 78% 123-91-1 38.98 10.99 50.03 69.00 1.04 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Picric acid 31.20 8.80 60.00 69.00 — 22% 23.35 6.58 70.07 69.00 99.0 Variables: Prepared by: 15.58 4.39 80.03 65.5 — Concentration of dioxane E. Königsberger and L.-C. 7.80 2.2 90.00 60.0 99.0 t/ °C=25 Königsberger 5. 48.75 16.25 35.00 61.0 Salicylic acid 44.98 14.99 40.03 68.0 Solubility of salicylic acid in water–dioxane mixtures 75% 37.47 12.49 50.04 71.0 Picric acid 29.77 9.92 60.31 71.0 Concentration of 25% 24.49 7.50 70.02 70.0 Temperature dioxane Solubility 14.97 4.99 80.04 67.0 / ␸ / −3 7.50 2.50 90.00 61.0 t °C 2 c1 mmol dm 6. 45.50 19.50 35.00 66.0 25 10 0.03 Salicylic acid 41.57 17.82 40.61 70.0 30 0.22 70% 34.95 14.98 50.07 73.5 35-62 a Picric acid 27.97 11.99 60.05 73.0 30% 70 2.73 21.00 9.00 70.00 71.5 80 3.06 13.34 5.72 80.95 67.0 100 3.05 3.50 1.50 95.00 53.0 a 7. 42.00 28.00 30.00 70.0 Two phases were formed, the dioxane-rich and water-rich containing 2.29 and 0.5 mmol dm−3 salicylic acid, respectively. Salicylic acid 37.80 25.20 37.00 79.0 60% 36.00 24.00 40.00 80.0 Auxiliary Information Picric acid 30.00 20.00 50.00 83.0 40% 24.00 16.00 60.00 83.0 92.0 Methods/Apparatus/Procedure: 18.00 12.00 70.00 83.0 — Excess amounts of “pure” salicylic acid were shaken in sealed bottles 12.00 8.00 80.00 75.0 93.0 with dioxane–water mixtures in a thermostat for 8–10 h. After 9.00 6.00 85.00 59.5 93.0 sedimentation of the solid phase, the solution was analyzed by titration 8. 37.50 37.50 25.00 76.0 with NaOH. Salicylic acid 35.00 35.00 30.00 89.0 Source and Purity of Materials: 50% 30.00 30.00 40.00 97.0 Not stated. Picric acid 25.00 25.00 50.00 98.0 50% 20.00 20.00 60.00 97.0 Estimated Errors: 15.00 15.00 70.00 96.0 Not stated. 10.00 10.00 80.00 85.0 7.50 7.50 85.00 62.0 Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 40A.N. Paruta, B.J. Sciarrone, and Auxiliary Information ͑o-hydroxybenzoic acid; salicylic N.G. Lordi, J. Pharm. Sci. 53, ͒ ͓ ͔ ͑ ͒ Methods/Apparatus/Procedure: acid ;C6H7O3; 69-72-7 1349 1964 . ͑2͒ 1,4-Diethylenedioxide The experiment was performed by polythermic method in sealed glass ͑ ͒ ͓ 1,4-dioxane ;C4H8O2; ampoules in an oil thermostat V.F. Alekseev, J. Russ. Chem. Soc. 8, 249 ͓ ͔ ͑ ͔͒ 123-91-1 1876 . ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=30.6 A. Goto and R. Goto

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Solubility of salicylic acid in water–1,4-dioxane mixture Polytherms of salicylic acid–antipyrine–water systems

Temperature Solubilityb Demixing Composition of saturated solutions temperature ␥ / −3 / −3 Dielectric 1 gdm c1 mol dm t/ °C Solvent system constanta ͑compiler͒ ͑compiler͒ Salicylic acid Antipyrine

100w1 100w2 Water 30.6 Water 78.5 3 0.022 ͑ ͒ ͑ ͒ / Section number compiler compiler 100w3 t °C Water–1,4-dioxane 14.5 250 1.81 3. 39.22 51.98 8.80 98.0 aThe dielectric constant of the binary mixture at the maximum solubility of Salicylic acid 40% 38.14 50.56 11.30 111.5 2-hydroxybenzoic acid. Antipyrine 60% 36.18 47.96 15.86 125.0 b ␥ In the original paper, the solubility was given as mg/ml of solution. The 1 32.96 38.76 32.00 156.0 value was calculated by the compiler. 22.62 29.98 47.40 162.0 15.02 19.91 65.07 163.0 Auxiliary Information 8.60 11.40 80.00 156.0 4.27 5.65 90.08 136.0 Methods/Apparatus/Procedure: 2.16 2.87 94.97 115.0 The experimental detail is given in the compilation of Ref. 40 for the 4. 44.75 44.75 10.50 108.0 salicylic acid–1-propanol–water system in Sec. 3.1.1.2. Salicylic acid 50% 39.69 39.69 20.63 145.0 Source and Purity of Materials: Antipyrine 50% 34.71 34.71 30.59 160.0 The solvents was puriﬁed by the method described by A. Weissberger et 30.00 30.00 40.00 167.0 al., Organic Solvents, 2nd ed. ͑Interscience, New York, 1955͒, Chaps. 4 17.50 17.50 65.00 166.0 and 5. 11.00 11.0 78.00 161.0 5.00 5.00 90.00 143.0 Estimated Errors: 2.50 2.50 95.00 118.0 Solubility: nothing speciﬁed. 5. 53.92 35.95 10.13 100.0 Temperature: precision Ϯ0.1 °C. Salicylic acid 60% 50.98 33.99 15.03 127.5 Antipyrine 40% 47.35 31.57 21.08 145.0 36.00 24.00 40.00 164.0 Components: Original Measurements: 24.00 16.00 60.00 166.0 ͑ ͒ ͑ 77 1 Benzoic acid, 2-hydroxy- o- I.L. Krupatkin, Zh. Obsh. 15.00 10.00 75.00 160.0 hydroxybenzoic acid; salicylic Khim. 25, 2189 ͑1955͓͒J. Gen. 5.97 3.98 90.05 143.0 acid͒;CH O ; ͓69-72-7͔ Chem. USSR ͑Engl. Transl.͒ 25, 7 6 3 3.00 2.00 95.00 119.0 ͑2͒ 2151 ͑1955͔͒. 2,3-Dimethyl-1-phenyl-3-pyrazolin-5-one 6. 63.00 27.00 10.00 79.0 ͑antipyrine; phenazone͒; Salicylic acid 70% 56.00 24.00 20.00 128.0 ͓ ͔ Antipyrine 30% C11H12N2O; 60-80-0 49.00 21.00 30.00 149.0 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 42.00 18.00 40.00 156.0 35.00 15.00 50.00 159.0 Variables: Prepared by: 28.00 12.00 60.00 161.0 Composition and temperature A. Goto and H. Miyamoto 21.00 9.00 70.00 160.0 14.00 6.00 80.00 154.0 Polytherms of salicylic acid–antipyrine–water systems 7.00 3.00 90.00 140.0 3.50 1.50 95.00 114.0 Demixing 7. 63.18 15.80 21.02 107.0 Composition of saturated solutions temperature Salicylic acid 80% 55.94 13.99 30.07 131.0 Antipyrine 20% 48.00 12.00 40.00 144.0 Salicylic acid Antipyrine 38.32 9.58 52.10 145.0 100w1 100w2 Water ͑ ͒ ͑ ͒ / 31.68 7.92 60.40 146.0 Section number compiler compiler 100w3 t °C 23.44 5.86 70.70 149.5 1. 12.00 48.00 40.00 98.0 15.84 3.96 80.20 148.0 Salicylic acid 20% 10.00 40.00 50.00 113.0 7.93 1.98 90.09 134.0 Antipyrine 80% 8.00 32.00 60.00 125.0 8. 63.00 7.00 30.00 94.0 6.00 24.00 70.00 133.0 Salicylic acid 90% 58.50 6.50 35.00 107.0 4.00 16.00 80.00 128.0 Antipyrine 10% 49.26 5.47 45.27 115.0 2.00 8.00 90.00 118.0 44.83 4.98 50.19 119.0 2. 27.00 63.00 10.00 52.0 35.43 3.94 60.63 124.0 Salicylic acid 30% 23.81 55.55 20.64 99.0 27.09 3.01 69.90 129.0 Antipyrine 70% 21.00 49.00 30.00 130.0 18.00 2.00 80.00 132.0 13.50 31.50 55.00 148.0 9.00 1.00 90.00 120.0 6.00 14.00 80.00 146.0 1.17 0.13 98.70 108.0 2.97 6.93 90.10 131.0 1.49 3.49 95.02 106.0

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Polytherms of salicylic acid–antipyrine–water systems Auxiliary Information

Demixing Source and Purity of Materials: Composition of saturated solutions temperature Pharmaceutical antipyrine and chemically pure grade salicylic acid were used. Water was twice distilled. Salicylic acid Antipyrine

100w1 100w2 Water Estimated Errors: ͑ ͒ ͑ ͒ / Section number compiler compiler 100w3 t °C Nothing speciﬁed.

9. 57.00 3.00 40.00 96.0 Salicylic acid 95% 47.50 2.50 50.00 104.0 Components: Original Measurements: Antipyrine 5% 38.00 2.00 60.00 108.0 ͑1͒ Benzoic acid, 2-hydroxy- 78I.L. Krupatkin, Zh. Obsh. 28.50 1.50 70.00 110.0 ͑o-hydroxybenzoic acid; salicylic Khim. 26,1050͑1956͓͒J. Gen. 18.63 0.98 80.39 116.0 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 Chem. USSR Engl. Transl. 26, 9.50 0.50 90.00 111.0 ͑2͒ 1197 ͑1956͔͒. 4-Dimethylamino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one ͑ Auxiliary Information 4-dimethylaminoantipyrine; aminopyrine; pyramidon͒; ͓ ͔ Methods/Apparatus/Procedure: C13H17N3O; 58-15-1 ͑ ͒ ͓ ͔ The experiment was performed by the polythermic method in sealed glass 3 Water; H2O; 7732-18-5 ampoules. The three-component system was studied by polythermic Variables: Prepared by: sections through their prisms taken from the edge for water to the plane for the binary system antipyrine–salicylic acid. Composition and temperature A. Goto and H. Miyamoto

Polytherms of salicylic acid–aminopyrine–water systems

Composition of Crystallization Stratiﬁcation saturated solutions temperature temperature

Salicylic Aminopyrine Water

Section acid 100w2 100w3 ͑ ͒ ͑ ͒ / / number 100w1 compiler compiler t °C t °C

1. 0.36 89.64 10 77.0 — Salicylic acid 0.32 79.68 20 71.0 — 0.4% 0.28 69.72 30 70.5 80.0 Aminopyrine 0.24 59.76 40 70.0 72.0 99.6% 0.20 49.80 50 70.0 70.0 0.18 44.82 55 70.0 70.0 0.16 39.84 60 70.0 70.0 0.12 29.88 70 69.5 41.5 0.08 19.92 80 68.5 76.0 0.04 9.96 90 61.0 — 2. 0.7 69.3 30 — 85.0 Salicylic acid 0.6 59.4 40 — 77.0 1.0% 0.5 49.5 50 — 74.0 Aminopyrine 0.4 39.6 60 — 73.0 99.0% 0.3 29.7 70 — 74.0 0.2 19.8 80 — 81.0 3. 3.0 57.0 40 99.0 133.5 Salicylic acid 2.5 47.5 50 92.5 157.0 5% 2.0 38.0 60 89.0 163.0 Aminopyrine 1.5 28.5 70 88.0 167.0 95% 1.0 19.0 80 93.0 161.0 0.9 17.1 82 100.0 155.0 4. 5.0 45.0 50 120.0 133.0 Salicylic acid 4.0 36.0 60 116.0 143.0 10% 3.0 27.0 70 114.0 144.0 Aminopyrine 2.5 22.5 75 114.0 144.0 90% 2.3 20.7 77 116.0 140.0 5. 18.0 27.0 55 95.0 103.5 Salicylic acid 16.0 24.0 60 82.0 107.6 40% 12.0 18.0 70 66.0 97.0 Aminopyrine 8.0 12.0 80 — 80.0 60%

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Polytherms of salicylic acid–aminopyrine–water systems

Composition of Crystallization Stratiﬁcation saturated solutions temperature temperature

Salicylic Aminopyrine Water

Section acid 100w2 100w3 ͑ ͒ ͑ ͒ / / number 100w1 compiler compiler t °C t °C

6. 32.4 39.6 28 80.0 100.0 Salicylic acid 31.5 38.5 30 72.0 110.0 45% 29.25 35.75 35 55.0 120.0 Aminopyrine 27.0 33.0 40 39.0 126.0 55% 22.5 27.5 50 — 129.5 18.0 22.0 60 — 129.0 13.5 16.5 70 — 124.0 9.0 11.0 80 — 108.0 6.75 8.25 85 — 95.0 4.5 5.5 90 — 77.0 7. 43.6 36.4 20 — 85.0 Salicylic acid 42.0 35.0 23 — 110.0 54.5% 38.15 31.85 30 — 128.0 Aminopyrine 32.7 27.3 40 — 136.0 45.5% 27.25 22.75 50 — 137.5 21.8 18.2 60 — 137.5 16.35 13.65 70 — 136.0 10.9 9.1 80 — 125.0 5.4 4.55 90 — 98.0 2.7 2.3 95 — 70.0 8. 53.29 29.71 17 — 70.0 Salicylic acid 51.36 28.64 20 — 105.5 64.2% 44.94 25.06 30 — 130.0 Aminopyrine 38.52 21.48 40 — 137.0 35.8% 32.10 17.90 50 — 138.5 28.89 16.11 55 — 138.5 25.68 14.32 60 — 138.5 19.26 10.74 70 — 137.0 12.84 7.16 80 — 128.5 6.42 3.58 90 — 108.0 3.21 1.79 95 — 89.0 1.93 1.07 97 — 65.0 9. 64.0 16.0 20 — 80.0 Salicylic acid 56.0 14.0 30 — 115.0 80% 48.0 12.0 40 — 125.0 Aminopyrine 40.0 10.0 50 — 126.5 20% 32.0 8.0 60 — 127.0 24.0 6.0 70 — 127.0 16.0 4.0 80 — 123.0 8.0 2.0 90 — 105.0 4.0 1.0 95 — 80.0 3.2 0.8 96 — 70.0 10. 67.5 7.5 25 — 69.0 Salicylic acid 63.0 7.0 30 — 92.0 90% 54.0 6.0 40 — 105.0 Aminopyrine 45.0 5.0 50 — 110.0 10% 36.0 4.0 60 — 113.0 27.0 3.0 70 — 113.0 18.0 2.0 80 — 112.0 13.5 1.5 85 — 110.0 9.0 1.0 90 — 101.0 4.5 0.5 95 — 75.0

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Auxiliary Information 3.2. Parabens and hydroxybenzoic acid

Methods/Apparatus/Procedure: salt–water–organic compound systems Stratiﬁcation was studied by the well-known Alekseev polythermal 3.2.1. Methylparaben method ͓V.F. Alekseev, J. Russ. Phys.-Chem. Soc. 8, 249 ͑1876͔͒ in sealed glass ampoules in an oil thermostat. 3.2.1.1. Alcohols

Source and Purity of Materials: Pharmacopoeia aminopyrine with m.p. 108 °C and c.p. salicylic acid with Components: Original Measurements: ͑ ͒ 54 m.p. 155 °C were used. Water was distilled twice. 1 Benzoic acid, 4-hydroxy-, R.H. Manzo, A.A. Ahumada, methyl ester ͑methyl and E. Luna, J. Pharm. Sci. 73, Estimated Errors: p-hydroxybenzoate; 1094 ͑1984͒. ͒ Nothing speciﬁed. methylparaben ;C8H8O3; ͓99-76-3͔ ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: Concentration of ethanol A. Goto and R. Goto 3.1.2. 3-Hydroxybenzoic acid t/ °C=25

Components: Original Measurements: Solubility of methylparaben in water–ethanol mixtures ͑1͒ Benzoic acid, 3-hydroxy- 79O. Aschan, Chem. Ztg. 37, Temperature Solvent Solubility ͑m-hydroxybenzoic acid͒; 1117 ͑1913͒. ͓ ͔ C7H6O3; 99-06-9 Ethanol Water Original 100w m /mol kg−1 ͑ ͒ ͑ ͒ 1 1 2 Methanoic acid formic acid ; t/ °C 100␸ 100␸ dataa ͑compiler͒ ͑compiler͒ ͓ ͔ 2 3 CH2O2; 64-18-6 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 25 0.0 100.0 2.89 0.289 0.289 10.0 90.0 3.81 0.381 0.381 Variables: Prepared by: 20.0 80.0 6.73 0.673 0.673 t/ °C=20.8 E. Königsberger and L.-C. 30.0 70.0 20.5 2.05 2.05 Königsberger 40.0 60.0 49.3 4.93 4.93 50.0 50.0 123 12.3 12.3 Solubility of 3-hydroxybenzoic acid in water–formic acid mixture at 60.0 40.0 196 19.6 19.6 20.8°C 70.0 30.0 265 26.5 26.5

Concentration aIn the original paper, the solubility was given as milligrams of the solute of formic acid Solubility per gram of solution. %a Original datab Original datac ␥ /gdm−3 c /mol dm−3 1 1 Auxiliary Information 95 2.37 2.7602 27.602 0.199 84 Methods/Apparatus/Procedure: aNot specified as mass % or volume %. The details of the method for the solubility measurements were described by R.H. Manzo, J. Pharm. Pharmacol. 34,486͑1982͒.A bIn the original paper, the solubility was given as grams per 100 g of 95% spectrophotometric determination of substrate concentration at ␭ was formic acid solution. max performed. cIn the original paper, the solubility was given as grams per 100 ml of solution. Source and Purity of Materials: 4-hydroxybenzoic acid methyl ester was obtained from Aldrich and Auxiliary Information purified by recrystallization. The melting point of purified methyl ester was 131 °C. The source of ethanol was not reported. Methods/Apparatus/Procedure: Suspensions of solid phase in 95% formic acid were shaken at ambient Estimated Errors: temperature for 5 h. A 5 ml saturated solution was weighed, and the Nothing specified. solvent was evaporated on a water bath or at ambient temperature. The residue was dried at 110 °C or higher and weighed.

Source and Purity of Materials: Components: Original Measurements: 47 The source of the materials was not stated. Melting points of ͑1͒ Benzoic acid, 4-hydroxy-, A.E. Beezer, S. Forster, W.-B. 3-hydroxybenzoic acid before and after recrystallization were 196.7 and methyl ester; ͑methyl Park, and G.J. Rimmer, 198.5 °C, respectively. p-hydroxybenzoate; Thermochim. Acta 178,59 ͒ ͑ ͒ methylparaben ;C8H8O3; 1991 . Estimated Errors: ͓99-76-3͔ ͑ ͒ ͓ ͔ Not stated. 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

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Variables: Prepared by: Solubility of methylparaben in water–ethanol mixtures Concentration of ethanol A. Goto and R. Goto T/K=288, 293, and 298 Concentration of Temperature ethanol Solubility

/ ␸ 3 Solubility of methylparaben in water–ethanol mixtures t °C 100 2 10 x1

Temperature Concentration of Solubility 40 0 0.683 / a / −3 T K ethanol % c1 mol dm 10 0.995 20 2.59 ϫ −3 288 0 8.31 10 30 10.00 95 1.54 50 0 0.755 ϫ −3 293 0 9.97 10 10 1.67 95 1.90 20 6.37 ϫ −2 298 0 1.14 10 30 17.00 95 28.0

aNo specific information on mass or volume percent was stated in the origi- Auxiliary Information nal paper. Methods/Apparatus/Procedure: Auxiliary Information Solvent mixtures were prepared by mixing exactly measured volumes of absolute ethanol and water. A suitable amount of solvent was introduced Methods/Apparatus/Procedure: into a stoppered test tube containing an excess of solute and was kept at The measurement of solubility was similar to that described by A.E. least 24 h in a constant-temperature bath with adequate shaking. Samples Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35, 350 were taken with a small diameter tube having a piece of sintered glass in ͑1983͒. Absorbance measurements were made at 258 nm. its end to avoid contamination with the solid. Pipettes and filter devices were previously heated in an oven to reach the same temperature as that Source and Purity of Materials: of the experiment. The ester concentration was determined The 4-hydroxybenzoic acid methyl ester was the gift of Apin Chemicals spectrophotometrically. Ltd. ͑Abingdon, Great Britain͒ and was used as received. The purity was specified as Ͼ99.5%. Ethanol was of Anala R grade. Source and Purity of Materials: Methylparaben was obtained from Aldrich and purified by Estimated Errors: recrystallization. The melting point was 398.4 K. Ethanol was analytical Nothing specified. grade obtained from Merck.

Estimated Errors: Nothing speciﬁed. Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 48R.H. Manzo and A.A. methyl ester ͑methyl Ahumada, J. Pharm. Sci. 79, p-hydroxybenzoate; 1109 ͑1990͒. Components: Original Measurements: ͒ ͑ ͒ 59 methylparaben ;C8H8O3; 1 Benzoic acid, 4-hydroxy-, J.T. Rubino and E.K. Obeng, J. ͓99-76-3͔ methyl ester ͑methyl Pharm. Sci. 80, 479 ͑1991͒. ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 p-hydroxybenzoate; ͑ ͒ ͓ ͔ ͒ 3 Water; H2O; 7732-18-5 methylparaben ;C8H8O3; ͓99-76-3͔ Variables: Prepared by: ͑2͒ 1,2-Propanediol ͑propylene ͒ ͓ ͔ Concentration of ethanol A. Goto and R. Goto glycol ;C3H8O2; 57-55-6 / ͑ ͒ ͓ ͔ t °C=15–50 3 Water; H2O; 7732-18-5

Variables: Prepared by: Solubility of methylparaben in water–ethanol mixtures Concentration of propylene A. Goto and R. Goto glycol Concentration of t/ °C=27 Temperature ethanol Solubility

/ ␸ 3 t °C 100 2 10 x1

15 0 0.185 10 0.267 20 0.465 30 1.46 25 0 0.286 10 0.476 20 0.3917 30 2.92

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Solubility of methylparaben in water–propylene glycol mixtures Auxiliary Information

Concentration of Methods/Apparatus/Procedure: Temperature propylene glycol Solubility Excess methylparaben was equilibrated with pure amide and with the amide–water mixture in 20 ml screw-cap vials. The vials were rotated for 100x1 24 h in a water bath regulated at 25 °C. After equilibrium was reached, a / ␸ ͑ ͒ t °C 2 −ln x1 compiler sample solution was withdrawn by a pipet from each vial, weighed, and diluted with methanol. The concentration of the methylparaben was 27 0.00 8.10 0.0304 determined spectrophotometrically. The densities of the saturated solutions 0.10 7.73 0.0439 were also measured. 0.20 7.31 0.0669 0.30 6.73 0.119 Source and Purity of Materials: ͑ ͒ 0.40 6.07 0.231 Methylparaben USP Rugh Chemical Co. was used without further 0.50 5.23 0.535 puriﬁcation. The amide was obtained commercially. The amide was exposed for 24 h to a molecular sieve to remove water, and then distilled 0.60 4.39 1.24 under reduced pressure in a nitrogen atmosphere. The middle 60% 0.70 3.75 2.35 fraction was collected. The purity of the puriﬁed amide was found to be 0.80 3.16 4.24 99.9% by gas chromatography. 0.90 2.70 6.72 1.00 2.36 9.44 Estimated Errors: Solubility: precision Ϯ2.0%. Ϯ Auxiliary Information Temperature: precision 0.001 °C.

Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 59 for the Components: Original Measurements: methylparaben–water system in Sec. 2.2.1.1. ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. Source and Purity of Materials: p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, The detail is given in the compilation of Ref. 59 for the methylparaben– ͒ ͑ ͒ methylparaben ;C8H8O5; 687 1977 . water system in Sec. 2.2.1.1. ͓99-78-3͔ ͑ ͒ N Estimated Errors: 2 Formamide, -methyl ͑N-methylformamide͒;CH NO; Solubility: the variation among triplicate samples was Ͻ5%. 2 5 ͓123-39-7͔ Temperature: Ϯ0.2 °C ͑the authors reported͒. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=25 A. Goto and R. Goto

3.2.1.2. Amides Solubility of methylparaben in water–N-methylformamide mixture

Temperature Solubility Components: Original Measurements: ͑ ͒ 80 Methylformamide–water 1 Benzoic acid, 4-hydroxy-, A.R. Giaquinto, R.E. a b methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. N-methylformamide mixture / p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, t °C x1 x1 methylparaben͒;CH O ; 687 ͑1977͒. 8 8 5 25 3.44ϫ10−4 0.262 ͓99-78-3͔ ͑ ͒ 2 Formamide; CH3NO; a ͓ ͔ Mole fraction solubility in pure amide solvent. 75-12-7 b ͑ ͒ ͓ ͔ Mole fraction solubility in 0.01 mole fraction amide-in-water cosolvent 3 Water; H2O; 7732-18-5 mixture. Variables: Prepared by: t/ °C=25 A. Goto and R. Goto Auxiliary Information Methods/Apparatus/Procedure: Solubility of methylparaben in water–formamide mixture The experimental detail is given in the compilation of Ref. 80 for the methylparaben–formamide–water system. Temperature Solubility Source and Purity of Materials: a b Formamide Formamide–water mixture The detail is given in the compilation of Ref. 80 for the methylparaben– / t °C x1 x1 formamide–water system.

25 3.06ϫ10−4 0.0660 Estimated Errors: Ϯ aMole fraction solubility in pure amide solvent. Solubility: precision 2.0%. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent Temperature: precision Ϯ0.001 °C. mixture.

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Solubility of methylparaben in water–N-propylformamide mixture Components: Original Measurements: 80 ͑1͒ Benzoic acid, 4-hydroxy-, A.R. Giaquinto, R.E. Temperature Solubility methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, N-propylformamide–water ͒ ͑ ͒ a b methylparaben ;C8H8O5; 687 1977 . N-propylformamide mixture ͓ ͔ / 99-78-3 t °C x1 x1 ͑2͒ Formamide, N-ethyl ͑ ͒ 25 4.45ϫ10−4 0.274 N-ethylformamide ;C3H7NO; ͓627-45-2͔ ͑ ͒ ͓ ͔ aMole fraction solubility in pure amide solvent. 3 Water; H2O; 7732-18-5 bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent Variables: Prepared by: mixture. t/ °C=25 A. Goto and R. Goto Auxiliary Information

Solubility of methylparaben in water–N-ethylformamide mixture Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 80 for the Temperature Solubility methylparaben–formamide–water system.

N-ethylformamide–water Source and Purity of Materials: a b N-ethylformamide mixture The detail is given in the compilation of Ref. 80 for the methylparaben– / t °C x1 x1 formamide–water system. ϫ −4 25 3.88 10 0.281 Estimated Errors: Solubility: precision Ϯ2.0%. aMole fraction solubility in pure amide solvent. Temperature: precision Ϯ0.001 °C. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent mixture.

Auxiliary Information Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. Methods/Apparatus/Procedure: methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. The experimental detail is given in the compilation of Ref. 80 for the p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ methylparaben–formamide–water system. methylparaben ;C8H8O5; 687 1977 . ͓99-78-3͔ Source and Purity of Materials: ͑2͒ Formamide, N,N-dimethyl The detail is given in the compilation of Ref. 80 for the methylparaben– ͑N,N-dimethylformamide͒; ͓ ͔ formamide–water system. C3H7NO; 68-12-2 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Estimated Errors: Solubility: precision Ϯ2.0%. Variables: Prepared by: Temperature: precision Ϯ0.001 °C. t/ °C=25 A. Goto and R. Goto

Solubility of methylparaben in water–N,N-dimethylformamide mixture Components: Original Measurements: 80 ͑1͒ Benzoic acid, 4-hydroxy-, A.R. Giaquinto, R.E. Temperature Solubility methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, N,N-dimethylformamide–water ͒ ͑ ͒ a b methylparaben ;C8H8O5; 687 1977 . N,N-dimethylformamide mixture ͓ ͔ / 99-78-3 t °C x1 x1 ͑2͒ Formamide, N-propyl ͑ ͒ 25 3.06ϫ10−4 0.0660 N-propylformamide ;C4H9NO; ͓6281-94-3͔ ͑ ͒ ͓ ͔ aMole fraction solubility in pure amide solvent. 3 Water; H2O; 7732-18-5 bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent Variables: Prepared by: mixture. t/ °C=25 A. Goto and R. Goto

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Auxiliary Information Comment and/or Additional Data: ͑ ͒ The mole fraction solubility xf f=1 of ester by volume Methods/Apparatus/Procedure: ͓ The experimental detail is given in the compilation of Ref. 80 for the fraction is deﬁned as S. H. Yalkowsky, S. C. Valvami, and methylparaben–formamide–water system. G. L. Amidon, J. Pharm. Sci. 65, 1488 ͑1976͔͒

Source and Purity of Materials: log x = log x + ␴␸ , ͑3͒ The detail is given in the compilation of Ref. 80 for the methylparaben– 10 f 10 w c formamide–water system. in which xf is the mole-fraction solubility of the solute at Estimated Errors: ␸ volume fraction c of the cosolvent and xw is the mole frac- Solubility: precision Ϯ2.0%. tion solubility of the solute in water. The term ␴ is deﬁned as Temperature: precision Ϯ0.001 °C. ␴ ͑␥0 ␥0͒͑ ͒/ ␥0 ␥0 =C w − c HYSA3 2.303kT, where w and c are the microscopic interfacial tensions between tetradecane ͑a model hydrophobic surface͒ and water and between tetrade- Components: Original Measurements: ͑ ͒ 55 cane and pure cosolvent, respectively. The hydrophobic sur- 1 Benzoic acid, 4-hydroxy-, R.E. Lindstrom, J. Pharm. Sci. ͑ ͒ methyl ester ͑methyl 68, 1141 ͑1979͒. face area for the solute is HYSA3 and C is a correction for p-hydroxybenzoate; the extremely small radius of curvature at the solute mol- ͒ methylparaben ;C8H8O3; ecule surface. Tests using aqueous cosolvent mixtures with ͓99-76-3͔ glycerin, propylene glycol, ethylene glycol, formamide, ͑ ͒ 2 Formamide, N,N-dimethyl methanol, and ethanol over the range from pure water to pure ͑N,N-dimethylformamide͒; ͓ ͔ cosolvent suggest that Eq. ͑3͒ is a reliable representation and C3H7NO; 68-12-2 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 that C has a relatively constant value near 0.5. ␸ The volume fractions a shown in the tables were calcu- Variables: Prepared by: lated according to ␸ =x v /͑x v +x v ͒, where x and v re- Concentration of amide A. Goto, R. Goto, and H. a a a a a w w t/ °C=25 Miyamoto fer to mole fractions and partial molar volumes, respectively, of the amide a and water w in the binary mixtures. The partial molar volumes employed were those corresponding to Solubility of methylparaben in water–N,N-dimethylformamide mixtures the appropriate amide mole fraction. Measurements equiva- Temperature Concentration of N,N-dimethylformamide Solubility lent to density determinations to 1 ppm were the bases for these volume data ͓A. R. Giaquinto, Ph. D. dissertation, Uni- / ␸ 3 t °C 2 x2 10 x1 versity of Connecticut, Storrs, 1972 ͑No. 73-9827, Univer- ͔͒ 25 0 0 0.246 sity Microﬁlms, Ann Arbor, MI . 0.0409 0.0100 0.431 Other detailed description is shown in the original paper. 0.0969 0.0249 0.830 0.1799 0.0499 2.04 Components: Original Measurements: 0.2513 0.0745 4.57 ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. 0.3150 0.0992 10.39 methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. 0.3686 0.1224 22.07 p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ 0.4137 0.1440 40.71 methylparaben ;C8H8O5; 687 1977 . 0.4534 0.1644 61.07 ͓99-78-3͔ ͑ ͒ 0.4869 0.1833 83.60 2 Formamide, N,N-diethyl ͑N,N-diethylformamide͒; ͓ ͔ C5H11NO; 617-84-5 ͑ ͒ ͓ ͔ Auxiliary Information 3 Water; H2O; 7732-18-5

Methods/Apparatus/Procedure: Variables: Prepared by: The data used in the preparation of this paper were reported by A. R. t/ °C=25 A. Goto and R. Goto Giaquinto, Ph. D. dissertation, University of Connecticut, Storrs, 1972 ͑No. 73-9827, University Microﬁlms, Ann Arbor, Mich.͒ and in Ref. 80. Solubility of methylparaben in water–N,N-diethylformamide mixture The procedures for obtaining these data entailed ͑a͒ preparation of the amide–water solvent systems by careful weighing of two ingredients, ͑b͒ equilibrium of excess methylparaben with the cosolvent at 25 °C, and ͑c͒ Temperature Solubility determination of the ester concentration in the resulting solutions using a N,N-diethylformamide–water standard UV spectrophotometric procedure. N,N-diethylformamidea mixtureb / Source and Purity of Materials: t °C x1 x1 The information is given in Ref. 80. 25 5.51ϫ10−4 0.447 Estimated Errors: aMole fraction solubility in pure amide solvents. Information is given in Ref. 80 bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent mixture.

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Auxiliary Information Variables: Prepared by: t/ °C=25 A. Goto and R. Goto Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 80 for the methylparaben–formamide–water system. Solubility of methylparaben in water–N-methylacetamide mixture

Source and Purity of Materials: Temperature Solubility The detail is given in the compilation of Ref. 80 for the methylparaben– formamide–water system. N-methylacetamide- N-methylacetamidea water mixtureb / Estimated Errors: t °C x1 x1 Solubility: precision Ϯ2.0%. ϫ −4 Temperature: precision Ϯ0.001 °C. 25 3.89 10 0.332

aMole fraction solubility in pure amide solvent. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent Components: Original Measurements: mixture. ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. Auxiliary Information p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ methylparaben ;C8H8O5; 687 1977 . Methods/Apparatus/Procedure: ͓99-78-3͔ The experimental detail is given in the compilation of Ref. 80 for the ͑ ͒ 2 Acetamide; C2H5NO; methylparaben–formamide–water system. ͓60-35-5͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Source and Purity of Materials: The detail is given in the compilation of Ref. 80 for the methylparaben– Variables: Prepared by: formamide–water system. t/ °C=25 A. Goto and R. Goto Estimated Errors: Solubility: precision Ϯ2.0%. Solubility of methylparaben in water–acetamide mixture Temperature: precision Ϯ0.001 °C.

Temperature Solubility

Acetamidea Acetamide–water mixtureb Components: Original Measurements: / 80 t °C x1 x1 ͑1͒ Benzoic acid, 4-hydroxy-, A.R. Giaquinto, R.E. methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. ϫ −4 25 5.51 10 0.447 p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ a methylparaben ;C8H8O5; 687 1977 . Mole fraction solubility in pure amide solvent. ͓99-78-3͔ b Mole fraction solubility in 0.01 mole fraction amide-in-water cosolvent ͑2͒ Acetamide, N-ethyl ͑ ͒ mixture. N-ethylacetamide ;C4H9NO; ͓625-50-3͔ Auxiliary Information ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Methods/Apparatus/Procedure: Variables: Prepared by: The experimental detail is given in the compilation of Ref. 80 for the t/ °C=25 A. Goto and R. Goto methylparaben–formamide–water system.

Source and Purity of Materials: Solubility of methylparaben in water–N-ethylacetamide mixture The detail is given in the compilation of Ref. 80 for the methylparaben– formamide–water system. Temperature Solubility

Estimated Errors: N-ethylacetamide–water Solubility: precision Ϯ2.0%. N-ethylacetamidea mixtureb / Temperature: precision Ϯ0.001 °C. t °C x1 x1

25 4.27ϫ10−4 0.328

Components: Original Measurements: aMole fraction solubility in pure amide solvent. 80 ͑1͒ Benzoic acid, 4-hydroxy-, A.R. Giaquinto, R.E. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent ͑ methyl ester methyl Lindstrom, J. Swarbrick, and A. mixture. p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ methylparaben ;C8H8O5; 687 1977 . Auxiliary Information ͓99-78-3͔ ͑2͒ Acetamide, N-methyl Methods/Apparatus/Procedure: ͑ ͒ N-methylacetamide ;C3H7NO; The experimental detail is given in the compilation of Ref. 80 for the ͓79-16-3͔ methylparaben–formamide–water system. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

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Source and Purity of Materials: Solubility of methylparaben in water–N,N-dimethylacetamide mixture The detail is given in the compilation of Ref. 80 for the methylparaben– formamide–water system. Temperature Solubility

Estimated Errors: N,N-dimethylacetamide–water a b Solubility: precision Ϯ2.0%. N,N-dimethylacetamide mixture / Temperature: precision Ϯ0.001 °C. t °C x1 x1 25 4.81ϫ10−4 0.453

Components: Original Measurements: aMole fraction solubility in pure amide solvent. 80 ͑1͒ Benzoic acid, 4-hydroxy-, A.R. Giaquinto, R.E. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent ͑ methyl ester methyl Lindstrom, J. Swarbrick, and A. mixture. p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ methylparaben ;C8H8O5; 687 1977 . Auxiliary Information ͓99-78-3͔ ͑2͒ Acetamide, N-propyl Methods/Apparatus/Procedure: ͑ ͒ N-propylacetamide ;C4H9NO; The experimental detail is given in the compilation of Ref. 80 for the ͓5331-48-6͔ methylparaben–formamide–water system. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Source and Purity of Materials: Variables: Prepared by: The detail is given in the compilation of Ref. 80 for the methylparaben– t/ °C=25 A. Goto and R. Goto formamide–water system.

Estimated Errors: Solubility of methylparaben in water–N-propylacetamide mixture Solubility: precision Ϯ2.0%. Temperature: precision Ϯ0.001 °C. Temperature Solubility

N-propylacetamide–water N-propylacetamidea mixtureb Components: Original Measurements: / 80 t °C x1 x1 ͑1͒ Benzoic acid, 4-hydroxy-, A.R. Giaquinto, R.E. methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. ϫ −4 25 5.24 10 0.315 p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ a methylparaben ;C8H8O5; 687 1977 . Mole fraction solubility in pure amide solvent. ͓99-78-3͔ b Mole fraction solubility in 0.01 mole fraction amide-in-water cosolvent ͑2͒ Acetamide, N,N-diethyl mixture. ͑N,N-diethylacetamide͒; ͓ ͔ C6H13NO; 685-91-6 Auxiliary Information ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Methods/Apparatus/Procedure: Variables: Prepared by: The experimental detail is given in the compilation of Ref. 80 for the t/ °C=25 A. Goto and R. Goto methylparaben–formamide–water system.

Source and Purity of Materials: Solubility of methylparaben in water–N,N-diethylacetamide mixture The detail is given in the compilation of Ref. 80 for the methylparaben– formamide–water system. Temperature Solubility

Estimated Errors: N,N-diethylacetamide–water a b Solubility: precision Ϯ2.0%. N,N-diethylacetamide mixture / Temperature: precision Ϯ0.001 °C. t °C x1 x1 25 6.69ϫ10−4 0.474

Variables: Prepared by: t/ °C=25 A. Goto and R. Goto

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Source and Purity of Materials: Temperature Solubility The detail is given in the compilation of Ref. 80 for the methylparaben– a formamide–water system. Propionamide / t °C x1 Propionamide–water mixture Estimated Errors: ϫ −4 Solubility: precision Ϯ2.0%. 25 3.62 10 not reported Ϯ Temperature: precision 0.001 °C. aMole fraction solubility in pure amide solvent. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent mixture. Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. Auxiliary Information methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, Methods/Apparatus/Procedure: ͒ ͑ ͒ The experimental detail is given in the compilation of Ref. 80 for the methylparaben ;C8H8O5; 687 1977 . ͓99-78-3͔ methylparaben–formamide–water system. ͑2͒ Acetamide, N,N-di-n-propyl Source and Purity of Materials: ͑N,N-di-n-propylacetamide͒; ͓ ͔ The detail is given in the compilation of Ref. 80 for the methylparaben– C8H17NO; 1116-24-1 ͑ ͒ ͓ ͔ formamide–water system. 3 Water; H2O; 7732-18-5

Variables: Prepared by: Estimated Errors: Ϯ t/ °C=25 A. Goto and R. Goto Solubility: precision 2.0%. Temperature: precision Ϯ0.001 °C.

Solubility of methylparaben in water–N,N-di-n-propylacetamide mixture

Components: Original Measurements: Temperature Solubility ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. N,N-di-n-propylacetamide–water methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. N,N-di-n-propylacetamidea mixtureb p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, / methylparaben͒;CH O ; 687 ͑1977͒. t °C x1 x1 8 8 5 ͓99-78-3͔ 25 ͑phase separation͒ 0.464 ͑2͒ Propionamide, N-methyl ͑N-methylpropionamide͒; a Mole fraction solubility in pure amide solvent. ͓ ͔ C4H9NO; 1187-58-2 bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 mixture. Variables: Prepared by: Auxiliary Information t/ °C=25 A. Goto and R. Goto Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 80 for the Solubility of methylparaben in water–N-methylpropionamide mixture methylparaben–formamide–water system. Temperature Solubility Source and Purity of Materials: N-methylpropionamide–water The detail is given in the compilation of Ref. 80 for the methylparaben– a b formamide–water system. N-methylpropionamide mixture / t °C x1 x1 Estimated Errors: 25 4.15ϫ10−4 0.211 Solubility: precision Ϯ2.0%. Ϯ Temperature: precision 0.001 °C. aMole fraction solubility in pure amide solvent. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent mixture. Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. Auxiliary Information methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, Methods/Apparatus/Procedure: ͒ ͑ ͒ The experimental detail is given in the compilation of Ref. 80 for the methylparaben ;C8H8O5; 687 1977 . ͓99-78-3͔ methylparaben–formamide–water system. ͑2͒ Propionamide; C H NO; 3 7 Source and Purity of Materials: ͓79-05-0͔ ͑ ͒ ͓ ͔ The detail is given in the compilation of Ref. 80 for the methylparaben– 3 Water; H2O; 7732-18-5 formamide–water system.

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Estimated Errors: Solubility of methylparaben in water–N-ethylpropionamide mixture Solubility: precision Ϯ2.0%. Temperature: precision Ϯ0.001 °C. Temperature Solubility

N-ethylpropionamide–water N-ethylpropionamidea mixtureb Components: Original Measurements: / t °C x1 x1 ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. 25 5.12ϫ10−4 0.321 p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ a methylparaben ;C8H8O5; 687 1977 . Mole fraction solubility in pure amide solvent. ͓99-78-3͔ bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent ͑2͒ Propionamide, N-ethyl mixture. ͑N-ethylpropionamide͒; ͓ ͔ C5H11NO; 5129-72-6 Auxiliary Information ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Methods/Apparatus/Procedure: Variables: Prepared by: The experimental detail is given in the compilation of Ref. 80 for the t/ °C=25 A. Goto and R. Goto methylparaben–formamide–water system.

Source and Purity of Materials: Solubility of methylparaben in water–N-ethylpropionamide mixture The detail is given in the compilation of Ref. 80 for the methylparaben– formamide–water system. Temperature Solubility Estimated Errors: N-ethylpropionamide–water Solubility: precision Ϯ2.0%. N-ethylpropionamidea mixtureb Temperature: precision Ϯ0.001 °C. / t °C x1 x1

25 4.42ϫ10−4 0.315 Components: Original Measurements: a Mole fraction solubility in pure amide solvent. ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. mixture. p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ methylparaben ;C8H8O5; 687 1977 . Auxiliary Information ͓99-78-3͔ ͑2͒ Propionamide, N,N-dimethyl Methods/Apparatus/Procedure: ͑N,N-dimethylpropionamide͒; ͓ ͔ The experimental detail is given in the compilation of Ref. 80 for the C5H11NO; 758-96-3 ͑ ͒ ͓ ͔ methylparaben–formamide–water system. 3 Water; H2O; 7732-18-5

Source and Purity of Materials: Variables: Prepared by: The detail is given in the compilation of Ref. 80 for the methylparaben– t/ °C=25 A. Goto and R. Goto formamide–water system.

Estimated Errors: Solubility of methylparaben in water–N,N-dimethylpropionamide mixture Solubility: precision Ϯ2.0%. Temperature: precision Ϯ0.001 °C. Temperature Solubility

N,N-dimethylpropionamide- N,N-dimethylpropionamidea water mixtureb Components: Original Measurements: / t °C x1 x1 ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. 25 5.54ϫ10−4 0.470 p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, ͒ ͑ ͒ a methylparaben ;C8H8O5; 687 1977 . Mole fraction solubility in pure amide solvent. ͓99-78-3͔ bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent ͑2͒ Propionamide, N-propyl mixture. ͑N-propylpropionamide͒; ͓ ͔ C5H13NO; 3217-86-5 Auxiliary Information ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Methods/Apparatus/Procedure: Variables: Prepared by: The experimental detail is given in the compilation of Ref. 80 for the t/ °C=25 A. Goto and R. Goto methylparaben–formamide–water system.

Source and Purity of Materials: The detail is given in the compilation of Ref. 80 for the methylparaben– formamide–water system.

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Estimated Errors: Solubility of methylparaben in water–sucrose mixtures Solubility: precision Ϯ2.0%. Temperature: precision Ϯ0.001 °C. Concentration of Temperature sucrose Solubilitya

␥ / −3 2 / −3 1 gdm 10 c1 mol dm Components: Original Measurements: / ͑ ͒ ͑ ͒ t °C 100w1 compiler compiler ͑1͒ Benzoic acid, 4-hydroxy-, 80A.R. Giaquinto, R.E. methyl ester ͑methyl Lindstrom, J. Swarbrick, and A. 25 0.0 2.26 1.49 p-hydroxybenzoate; LoSurdo, J. Solution Chem. 6, 7.5 2.24 1.47 ͒ ͑ ͒ methylparaben ;C8H8O5; 687 1977 . 18.5 2.21 1.45 ͓99-78-3͔ 31.5 2.15 1.41 ͑2͒ Propionamide, N,N-diethyl 41.5 2.12 1.39 ͑N,N-diethylpropionamide͒; ͓ ͔ 46.0 2.11 1.39 C7H15NO; 1114-51-8 ͑ ͒ ͓ ͔ 63.5 2.02 1.33 3 Water; H2O; 7732-18-5

Variables: Prepared by: aIn the original paper, the solubility was given as mg of ester per ml of t/ °C=25 A. Goto and R. Goto solution.

Auxiliary Information Solubility of methylparaben in water–N,N-diethylpropionamide mixture Methods/Apparatus/Procedure: Temperature Solubility An aqueous sucrose solution was prepared from commercial granulated sugar and de-ionized or distilled water. Details of the solubility N,N-diethylpropionamide–water a b determination at 25 °C were described by A.N. Paruta, J. Pharm. Sci. 53, N,N-diethylpropionamide mixture 1252 ͑1964͒; A.N. Paruta and B.B. Sheth, J. Pharm. Sci. 55,896͑1966͒. / t °C x1 x1 Equilibrium was reached in 72 h. All solubility runs were done at least four times. After allowing to settle in a water bath for several hours, clear 25 ͑phase separation͒ 0.468 sample solutions were readily obtained. Solubilities were determined by a aMole fraction solubility in pure amide solvent. gravimetric procedure. bMole fraction solubility in 0.01 mole fraction amide-in-water cosolvent mixture. Source and Purity of Materials: Methylparaben was obtained from the Nepera Chem. Co. The solute was Auxiliary Information used without further puriﬁcation.

Methods/Apparatus/Procedure: Estimated Errors: The experimental detail is given in the compilation of Ref. 80 for the Solubility: nothing speciﬁed. methylparaben–formamide–water system. Temperature: precision Ϯ0.1 °C.

Source and Purity of Materials: The detail is given in the compilation of Ref. 80 for the methylparaben– formamide–water system.

Estimated Errors: Solubility: precision Ϯ2.0%. 3.2.1.4. Polyethylene glycol derivative Temperature: precision Ϯ0.001 °C.

Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 58F. Shihab, W. Shefﬁeld, J. methyl ester ͑methyl Sprowls, and J. Nematollahi, J. p-hydroxybenzoate; Pharm. Sci. 59, 1574 ͑1970͒. ͒ 3.2.1.3. Carbohydrate methylparaben ;C8H8O3; ͓99-76-3͔ ͑2͒ Poly͑oxy-1,1,2-ethanediyl͒, Components: Original Measurements: ␣-hydro-␻-hydroxy- ͑1͒ Benzoic acid, 4-hydroxy-, 51A.N. Paruta and B.B. Sheth, J. ͑polyethylene glycol 400; PEG ͒ ͑ ͒ methyl ester ͑methyl Pharm. Sci. 55, 1208 ͑1966͒. 400 ; C2H4O nH2O; p-hydroxybenzoate; ͓25322-68-3͔ ͒ ͑ ͒ ͓ ͔ methylparaben ;C8H8O3; 3 Water; H2O; 7732-18-5 ͓99-76-3͔ ͑2͒ ␣-D-Glucopyranoside, Variables: Prepared by: ␤-D-fructofuranosy ͑sucrose; Concentration of PEG 400 A. Goto and R. Goto ͒ ͓ ͔ t/ °C=27 sugar ;C12H22O11; 57-50-1 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: Concentration of sucrose A. Goto and R. Goto t/ °C=25

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Solubility of methylparaben in water–PEG 400 mixtures Solubility of methylparaben in propylparaben–water mixture

Temperature Concentration of PEG 400 Solubility Concentration of Temperature propylparaben Solubility / ␥ / −3 / −3 t °C 100w2 1 gdm c1 mol dm / a ␥ / −3 / −3 t °C % 1 gdm c1 mol dm 27 0 2.512 0.0165 20 9.150 0.0601 20 0 1.91 0.0126 40 40.700 0.2675 0.04 2.03 0.0134 60 174.00 1.1410 a 80 337.75 2.2199 The compiler assumed mass % units. 100 343.75 2.2594 Auxiliary Information

Methods/Apparatus/Procedure: Auxiliary Information The supersaturation method was used. Either pure, crystalline Methods/Apparatus/Procedure: methylparaben, or a mixture of methylparaben and propylparaben was The solubility of methylparaben in PEG–water mixed solvent was added to water. The mixtures were shaken in a thermostat for 3 h at determined by adding an excess of solid methylparaben to the mixed 30 °C, and then the solutions were further shaken for 1 h at 20 °C. The solvent and shaking the mixture in a water bath at 27 °C for 24 h. The concentration of the methyl ester was determined by UV analysis of the saturated solution was carried out by a UV spectrophotometry. spectrophotometer ͑Beckman DB͒. For UV analysis, a known volume of Source and Purity of Materials: the sample was diluted further with 50% ethanol using volumetric flasks. The absorbance values were recorded at 256 m␮. The standard molar No information was given. solution of methylparaben was prepared by weighing accurately a Estimated Errors: precalculated quantity of methylparaben in a volumetric flask and then Nothing specified. dissolving the solid in 60% PEG–water by gentle shaking.

Source and Purity of Materials: All the compounds were analytical grade. Methylparaben was obtained Components: Original Measurements: from Matheson Coleman & Bell. Polyethylene glycol was supplied by ͑1͒ Benzoic acid, 4-hydroxy-, 49R. Huttenrauch and I. Keiner, City Chemical Corp. The solvents were prepared by weighed quantities of methyl ester ͑methyl Pharmazie 31,489͑1976͒. polyethylene glycol 400 and water. p-hydroxybenzoate; methylparaben͒;CH O ; Estimated Errors: 8 8 3 ͓99-76-3͔ ͑ ͒ Solubility: nothing speciﬁed. 2 Benzoic acid, 4-hydroxy-, propyl ester ͑propyl Temperature: precision Ϯ0.1 °C. p-hydroxybenzoate; ͒ propylparaben ;C10H12O3; ͓94-13-3͔ ͑ ͒ ͓ ͔ 3 Water-d2;D2O; 7789-20-0

Variables: Prepared by: 3.2.1.5. Aromatic compound Concentration of propylparaben E. Königsberger and L.-C. t/ °C=20 Königsberger

Components: Original Measurements: Solubility of methylparaben in propylparaben–water-d2 mixture ͑1͒ Benzoic acid, 4-hydroxy-, 49R. Huttenrauch and I. Keiner, methyl ester ͑methyl Pharmazie 31,489͑1976͒. Concentration of p-hydroxybenzoate; ͒ Temperature propylparaben Solubility methylparaben ;C8H8O3; ͓99-76-3͔ / a ␥ / −3 / −3 t °C % 1 gdm c1 mol dm ͑2͒ Benzoic acid, 4-hydroxy-, 1-propyl ester ͑propyl 20 0 1.74 0.0115 p-hydroxybenzoate; 0.04 1.80 0.0119 ͒ propylparaben ;C10H12O3; ͓94-13-3͔ athe compiler assumed mass % units. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: Concentration of propylparaben E. Königsberger and L.-C. t/ °C=20 Königsberger

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Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 4-hydroxy-, 48R.H. Manzo and A.A. The supersaturation method was used. Either pure, crystalline ethyl ester ͑ethyl Ahumada, J. Pharm. Sci. 79, methylparaben, or a mixture of methylparaben and propylparaben was p-hydroxybenzoate; 1109 ͑1990͒. ͒ added to water-d2. The mixtures were shaken in a thermostat for 3 h at ethylparaben ;C9H10O3; 30 °C, and then the solutions were further shaken for 1 h at 20 °C. The ͓120-47-8͔ ͑ ͒ ͓ ͔ concentration of the methyl ester was determined by UV 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ spectrophotometry. 3 Water; H2O; 7732-18-5

Source and Purity of Materials: Variables: Prepared by: No information was given. Concentration of ethanol A. Goto and R. Goto t/ °C=15–50 Estimated Errors: Nothing speciﬁed. Solubility of ethylparaben in water–ethanol mixtures

Concentration of Temperature ethanol Solubility 3.2.2. Ethylparaben / ␸ 3 t °C 100 2 10 x1 3.2.2.1. Alcohols 15 0 0.0211 10 0.0423 20 0.0776 Components: Original Measurements: 30 0.346 ͑1͒ Benzoic acid, 4-hydroxy-, 47A.E. Beezer, S. Forster, W.-B. 25 0 0.0332 ethyl ester ͑ethyl Park, and G.J. Rimmer, 10 0.0691 p-hydroxybenzoate; Thermochim. Acta 178,59 ͒ ͑ ͒ 20 0.166 ethylparaben ;C9H10O3; 1991 . ͓120-47-8͔ 30 0.704 ͑ ͒ ͓ ͔ 40 0 0.0707 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 10 0.153 20 0.493 Variables: Prepared by: 30 — Concentration of ethanol A. Goto and R. Goto 50 0 0.117 T/K=288, 293, and 298 10 0.275 20 1.12 Solubility of ethylparaben in water–ethanol mixtures 30 —

Temperature Concentration of Solubility / a / −3 Auxiliary Information T K ethanol, % c1 mol dm

288 0 2.75ϫ10−3 Methods/Apparatus/Procedure: 95 1.93 The experimental detail is given in the compilation of Ref. 48 for the 293 0 3.37ϫ10−3 methylparaben–ethanol–water system in Sec. 3.2.1.1. 95 2.19 Source and Purity of Materials: ϫ −3 298 0 4.09 10 Ethylparaben was obtained from Aldrich and purified by recrystallization. 95 2.87 The melting point was 369.2 K. Ethanol was analytical grade obtained aNo specific information on mass or volume percent was stated in the origi- from Merck. nal paper. Estimated Errors: Auxiliary Information Nothing specified.

Methods/Apparatus/Procedure: The measurement of solubility was similar to that described by A.E. Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35, 350 ͑1983͒. Absorbance measurements were made at 258 nm.

Source and Purity of Materials: The methylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great Britain͒ and was used as received. The purity was speciﬁed as Ͼ99.5%. Ethanol was of Anala R grade.

Estimated Errors: Nothing speciﬁed.

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Variables: Prepared by: Components: Original Measurements: Concentration of sucrose A. Goto and R. Goto 59 ͑1͒ Benzoic acid, 4-hydroxy-, J.T. Rubino and E.K. Obeng, J. t/ °C=25 ethyl ester ͑ethyl Pharm. Sci. 80, 479 ͑1991͒. p-hydroxybenzoic acid; ͒ Solubility of ethylparaben in water–sucrose mixtures ethylparaben ;C9H10O3; ͓120-47-8͔ ͑2͒ 1,2-Propanediol ͑propylene Concentration of ͒ ͓ ͔ Temperature sucrose Solubilitya glycol ;C3H8O2; 57-55-6 ͑3͒ Water; H O; ͓7732-18-5͔ 2 ␥ / −3 2 / −3 1 gdm 10 c1 mol dm / ͑ ͒ ͑ ͒ Variables: Prepared by: t °C 100w1 compiler compiler Concentration of propylene A. Goto and R. Goto 25 0.0 1.06 6.38 glycol 7.5 1.04 6.26 t/ °C=27 18.5 1.02 6.14 31.5 1.01 6.08 Solubility of ethylparaben in propylene glycol–water mixtures 41.5 1.00 6.02 46.0 0.99 5.96 Concentration of 63.5 0.95 5.72 Temperature propylene glycol Solubility aIn the original paper, the solubility was given as milligrams of ester per 100x1 milliliters of solution. / ␸ ͑ ͒ t °C 2 −ln x1 compiler Auxiliary Information 27 0.00 9.19 0.0102 0.10 8.83 0.0146 Methods/Apparatus/Procedure: 0.20 8.22 0.0269 The experimental detail is given in the compilation of Ref. 51 for the 0.30 7.65 0.0476 methylparaben–sucrose–water system in Sec. 3.2.1.3. 0.40 7.02 0.0894 Source and Purity of Materials: 0.50 6.00 0.248 Ethylparaben was obtained from Heyden Chem. Corp. The solute was 0.60 5.10 0.610 used without further puriﬁcation. 0.70 4.28 1.38 0.80 3.67 2.55 Estimated Errors: 0.90 3.03 4.83 Solubility: nothing speciﬁed. 1.00 2.55 7.81 Temperature: precision Ϯ0.1 °C.

Auxiliary Information

Methods/Apparatus/Procedure: 3.2.2.3. Organic salt The experimental detail is given in the compilation of Ref. 59 for the methylparaben–water system in Sec. 2.2.1.1. Components: Original Measurements: Source and Purity of Materials: ͑1͒ Benzoic acid, 4-hydroxy-, 5A. Goto, F. Endo, and K. Ito, Ethylparaben of high purity was obtained from Sigma Chemical Company ethyl ester ͑ethyl Chem. Pharm. Bull. 25,1165 and used as received from the supplier. The melting point was 116 °C and p-hydroxybenzoate; ͑1977͒. the value agreed with that reported in Ref. 46. ͒ ethylparaben ;C9H10O3; ͓120-47-8͔ Estimated Errors: ͑2͒ Sulfuric acid monododecyl Solubility: the variation among triplicate samples was Ͻ5%. ester, sodium salt ͑sodium lauryl Ϯ ͑ ͒ Temperature: 0.2 °C the authors reported . sulfate; sodium dodecyl sulfate͒; ͓ ͔ C12H25O4SNa; 151-21-3 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 3.2.2.2. Carbohydrate Variables: Prepared by: Concentration of sodium lauryl A. Goto sulfate Components: Original Measurements: t/ °C=27 ͑1͒ Benzoic acid, 4-hydroxy-, 51A.N. Paruta and B.B. Sheth, J. ethyl ester ͑ethyl Pharm. Sci. 55, 1208 ͑1966͒. p-hydroxybenzoate; Solubility of ethylparaben in water–sodium lauryl sulfate mixture ͒ ethylparaben ;C9H10O3; ͓120-47-8͔ Temperature Concentration of sodium lauryl sulfate Solubility ͑2͒ ␣-D-Glucopyranoside, t/ °C 103c /mol dm−3 103c /mol dm−3 ␤-D-fructofuranosy ͑sucrose; 2 1 ͒ ͓ ͔ sugar ;C12H22O11; 57-50-1 27 0 5.4 ͑3͒ Water; H O; ͓7732-18-5͔ 2 40 22.7

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Auxiliary Information Source and Purity of Materials: All the compounds were analytical grade. Ethylparaben was obtained from Methods/Apparatus/Procedure: Matheson Coleman & Bell. Polyethylene glycol was supplied by City The excess paraben was put in glass-stoppered flasks containing 10 ml of Chemical Corp. The solvents were prepared by weighed quantities of water or sodium lauryl sulfate ͑SLS͒ solutions. The flasks were then polyethylene glycol 400 and water. shaken at 27.0Ϯ0.1 °C in an incubator ͑Taiyo incubator, M-I type͒ to attain an equilibrium. After a given volume of the supernatant was diluted Estimated Errors: adequately with water, the concentration of the paraben in the solution Solubility: nothing specified. was determined by measuring the absorbance at 256 nm ͑HITACHI 101 Temperature: precision Ϯ0.1 °C. Spectrophotometer͒. A concentration of the paraben was measured by diluting each fraction to be below 1 mM with respect to SLS, since no interference by the presence of SLS below 1 mM was observed for the Components: Original Measurements: determination of the paraben. ͑1͒ Benzoic acid, 4-hydrdoxy-, 42T.C. Corby and P.H. Elworthy, ͑ Source and Purity of Materials: ethyl ester ethyl J. Pharm. Pharmacol. 23, Suppl, ͑ ͒ Ethylparaben was of reagent grade. Sodium lauryl sulfate was purified by p-hydroxybenzoate; 39S 1971 . ͒ the method of S. Miyamoto, Bull. Chem. Soc. Jpn. 33, 371 ͑1959͒. Water ethylparaben ;C9H10O3; ͓ ͔ was purified by distillation from de-ionized water. 120-47-8 ͑2͒ Poly͑oxy-1,2-ethanediyl͒, Estimated Errors: ␣-hydro-␻-hydroxy- ͑ Solubility: nothing specified. polyethylene glycol 1000; PEG ͒ ͑ ͒ Temperature: precision Ϯ0.1 °C. 1000 ; C2H4O nH2O; ͓25322-68-3͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared By: Concentration of PEG 1000 A. Goto and R. Goto t/ °C=20 3.2.2.4. Polyethylene glycol derivatives Solubility of ethylparaben in water–PEG 1000 mixtures

Components: Original Measurements: Temperature Concentration of PEG 1000a Solubility ͑1͒ Benzoic acid, 4-hydroxy-, 58F. Shihab, W. Shefﬁeld, J. ethyl ester ͑ethyl Sprowls, and J. Nematollahi, J. / / / −1 t °C %w v m1 mmol kg p-hydroxybenzoate; Pharm. Sci. 59, 1574 ͑1970͒. ͒ ethylparaben ;C9H10O3; 20 10 10.5 ͓120-47-8͔ 20 35.0 ͑2͒ Poly͑oxy-1,1,2-ethanediyl͒, 30 69.3 ␣-hydro-␻-hydroxy- a ͑polyethylene glycol 400; PEG In the original paper, %w/v was given as the concentration units. ͒ ͑ ͒ 400 ; C2H4O nH2O; ͓71767-64-1͔ Auxiliary Information ͑3͒ Water; H O; ͓7732-18-5͔ 2 Methods/Apparatus/Procedure: Variables: Prepared by: The solubility was determined as described by P.H. Elworthy and F.J. ͑ ͒ Concentration of PEG 400 A. Goto and R. Goto Lipscomb, J. Pharm. Pharmacol. 20,790 1968 . The solution was assayed t/ °C=27 by ultraviolet spectroscopy. Source and Purity of Materials: Solubility of ethylparaben in water–PEG 400 mixtures Ethylparaben ͑BDH Ltd., Lab. reagent͒ was recrystallized from distilled water and dried overnight at 40 °C in a vacuum over phosphorous Temperature Concentration of PEG 400 Solubility pentaoxide. PEG of BDH Laboratory Reagent was used as received.

/ ␥ / −3 / −3 Estimated Errors: t °C 100w2 1 gdm c1 mol dm Solubility: the standard error was Ϯ0.06 mmol kg−1. 27 0 1.030 0.0062 20 4.063 0.0244 40 18.750 0.1128 Components: Original Measurements: 60 141.690 0.8527 ͑1͒ Benzoic acid, 4-hydrdoxy-, 42T.C. Corby and P.H. Elworthy, 80 362.500 2.0116 ethyl ester ͑ethyl J. Pharm. Pharmacol. 23, Suppl, 100 365.000 2.0255 p-hydroxybenzoate; 39S ͑1971͒. ͒ ethylparaben ;C9H10O3; ͓120-47-8͔ Auxiliary Information ͑2͒ 3,6,9,12,15-Pentaoxaheptadecane-1,17-diol Methods/Apparatus/Procedure: ͑hexaoxyethylene glycol; All procedures were identical to those given in the compilation of Ref. 58 ͒ ͓ ͔ hexagol ;C12H26O7; 2615-15-8 for the methylparaben–PEG 400–water system in Sec. 3.2.1.4. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

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Variables: Prepared by: Auxiliary Information Concentration of hexagol A. Goto and R. Goto t/ °C=20 Methods/Apparatus/Procedure: Saturation solubilities of solid compound were determined as described by P.H. Elworthy and F.J. Lipscomb, Pharm. Pharmacol. 20,790͑1968͒.The Solubility of ethylparaben in water–hexagol mixtures analysis was carried out by UV spectroscopy.

Temperature Concentration of hexagola Solubility Source and Purity of Materials: Ethylparaben ͑BDH Ltd., Lab. reagent͒ was recrystallized from distilled / / / −1 t °C %w v m1 mmol kg water and dried overnight at 40 °C in a vacuum over phosphorous pentaoxide. Cetomacrogol 1000 B.P.C. ͑Macarthy’s Ltd.͒ was used as 20 10 7.38 received. The number of oxyethylene units was 21.5 and the molecular 40 25.5 weight was taken as 1210.

aIn the original paper, %w/v was given as the concentration units. Estimated Errors: Solubility: the standard error was Ϯ0.06 mmol kg−1. Auxiliary Information

Methods/Apparatus/Procedure: Saturation solubility of solid ethylparaben was determined as described by Components: Original Measurements: P.H. Elworthy and F.J. Lipscomb, J. Pharm. Pharmacol. 20,790͑1968͒. ͑1͒ Benzoic acid, 4-hydrdoxy-, 42T.C. Corby and P.H. Elworthy, Solubility was determined by a spectrophotometer. ethyl ester ͑ethyl J. Pharm. Pharmacol. 23, Suppl, p-hydroxybenzoate; 39S ͑1971͒. Source and Purity of Materials: ͒ ethylparaben ;C9H10O3; The ethylparaben ͑BDH Ltd., Lab. reagent͒ was recrystallized from ͓120-47-8͔ distilled water, then dried overnight at 40 °C in a vacuum over ͑2͒ Heptaoxyethylene glycol ͑ ͒ phosphorous pentaoxide. Hexagol was prepared by the method of P.H. monohexadecyl ether C16E7 ; ͑ ͒ ͑ ͒ ͓͔ Elworthy and C.B. Macfarlane, J. Chem. Soc. 1963, 907. CH3 CH2 15O CH2CH2O 7H; ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Estimated Errors: Solubility: the standard error was Ϯ0.06 mmol kg−1. Variables: Prepared by:

Concentration of C16E7 A. Goto and R. Goto t/ °C=20 Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydrdoxy-, 42T.C. Corby and P.H. Elworthy, Solubility of ethylparaben in water–C16E7 mixtures ethyl ester ͑ethyl J. Pharm. Pharmacol. 23, Suppl, ͑ ͒ p-hydroxybenzoate; 39S 1971 . Temperature Concentration of C E a Solubility ͒ 16 7 ethylparaben ;C9H10O3; ͓ ͔ / / / −1 120-47-8 t °C %w v m1 mmol kg ͑2͒ Polyethylene glycol 1000 monocetyl ethers ͑cetomacrogol 20 1 15.9 1000͒; 227.6 ͑ ͒ ͑ ͒ CH3 CH2 mO CH2OCH2 nCH2OH ͑m=15or17,n=19to23͒; ͓͔ aIn the original paper, %w/v was given as the concentration units. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Auxiliary Information Variables: Prepared by: Concentration of cetomacrogol A. Goto and R. Goto Methods/Apparatus/Procedure: 1000 Saturation solubility of the solid compound was determined as described t/ °C=20 by P.H. Elworthy and F. J. Lipscomb, J. Pharm. Pharmacol. 20,790 ͑1968͒. The analysis was carried out by UV spectroscopy.

Solubility of ethylparaben in water–cetomacrogol 1000 mixtures Source and Purity of Materials: Ethylparaben ͑BDH Ltd., Laboratory reagent͒ was recrystallized from Temperature Concentration of cetomacrogol 1000a Solubility distilled water, then dried overnight at 40 °C in a vacuum over phosphorous pentaoxide. Heptaoxyethylene glycol monohexadecyl ether / / / −1 t °C %w v m1 mmol kg prepared by P.H. Elworthy and C.B. Macfarlane, J. Chem. Soc. 1963, 907, was chromatographed to yield white crystals. 20 1 13.9 5 45.1 Estimated Errors: 10 78.6 Nothing speciﬁed.

aIn the original paper, %w/v was given as the concentration units.

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3.2.3. Propylparaben Solubility of propylparaben in water–propylene glycol mixtures

Concentration of Temperature propylene glycol Solubility

100x1 3.2.3.1. Alcohols / ␸ ͑ ͒ t °C 2 −ln x1 compiler

27 0.00 10.04 0.004 36 Components: Original Measurements: 0.10 9.60 0.006 77 ͑1͒ Benzoic acid, 4-hydroxy-, 47A.E. Beezer, S. Forster, W-B. 0.20 9.12 0.010 9 propyl ester; ͑propyl Park, and G.J. Rimmer, p-hydroxybenzoate; Thermochim. Acta 178, 59 0.30 8.50 0.020 3 ͒ ͑ ͒ 0.40 7.57 0.051 6 propylparaben ;C10H12O3; 1991 . ͓94-13-3͔ 0.50 6.43 0.161 ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 0.60 5.54 0.393 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 0.70 4.56 1.05 0.80 3.71 2.45 Variables: Prepared by: 0.90 2.87 5.67 T/K=288.2, 293.2, and 298.2. A. Goto and R. Goto 1.00 2.45 8.63

Solubility of propylparaben in water–ethanol mixtures Auxiliary Information

Temperature Concentration of Solubility Methods/Apparatus/Procedure: / a / −3 T K ethanol % c1 mol dm The experimental detail is given in the compilation of Ref. 59 for the methylparaben–water system in Sec. 2.2.1.1. 288.2 0 2.05ϫ10−3 95 2.23 Source and Purity of Materials: 293.2 0 2.41ϫ10−3 Propylparaben of high purity was obtained from Sigma Chemical Co. and 95 2.22 used as received from the supplier. The melting point was 96 °C and the 298.2 0 2.57ϫ10−3 value agreed with that reported in Ref. 46. 95 2.31 Estimated Errors: a Ͻ No speciﬁc information on mass or volume percent was stated in the origi- Solubility: the variation among triplicate samples was 5%. Ϯ ͑ ͒ nal paper. Temperature: 0.2 °C the authors reported .

Auxiliary Information

Source and Purity of Materials: The propylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great Components: Original Measurements: 51 Britain͒ and was used as received. The purity was speciﬁed as Ͼ99.5%. ͑1͒ Benzoic acid, 4-hydroxy-, A.N. Paruta and B.B. Sheth, J. Ethanol was of Anala R grade. propyl ester ͑propyl Pharm. Sci. 55, 1208 ͑1966͒. p-hydroxybenzoate; ͒ Estimated Errors: propylparaben ;C10H12O3; Nothing speciﬁed. ͓94-13-3͔ ͑2͒ ␣-D-Glucopyranoside, ␤-D-fructofuranosy ͑sucrose; ͒ ͓ ͔ sugar ;C12H22O11; 57-50-1 Components: Original Measurements: ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 ͑1͒ Benzoic acid, 4-hydroxy-, 59J.T. Rubino and E.K. Obeng, J. propyl ester ͑propyl Pharm. Sci. 80, 479 ͑1991͒. Variables: Prepared by: p-hydroxybenzoate; Concentration of sucrose A. Goto and R. Goto ͒ propylparaben ;C10H12O3; t/ °C=25 ͓94-13-3͔ ͑2͒ 1,2-Propanediol ͑propylene ͒ ͓ ͔ glycol ;C3H8O2; 57-55-6 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: Concentration of propylene A. Goto and R. Goto glycol t/ °C=27

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Solubility of propylparaben in water–sucrose mixtures Auxiliary Information

Concentration of Methods/Apparatus/Procedure: Temperature sucrose Solubilitya All procedures were identical to those given in the compilation of Ref. 58 for the methylparaben–PEG 400–water system in Sec. 3.2.1.4. ␥ / −3 2 / −3 1 gdm 10 c1 mol dm / ͑ ͒ ͑ ͒ t °C 100w1 compiler compiler Source and Purity of Materials: All the compounds were analytical grade. Propylparaben was obtained 25 0.0 0.516 2.86 from Matheson Coleman & Bell. Polyethylene glycol was supplied by 7.5 0.510 2.83 City Chemical Corp. The solvents were prepared by weighed quantities of 18.5 0.500 2.77 polyethylene glycol 400 and water. 31.5 0.497 2.76 Estimated Errors: 41.5 0.493 2.74 Solubility: nothing speciﬁed. 46.0 0.491 2.72 Temperature: precision Ϯ0.1 °C. 63.5 0.484 2.69 aIn the original paper, the solubility was given as milligrams of ester per milliliter of solution.

Auxiliary Information 3.2.4. Butylparaben

Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 51 for the methylparaben–sucrose–water system in Sec. 3.2.1.3. 3.2.4.1. Alcohols

Source and Purity of Materials: Propylparaben was obtained from the Nepera Chem. Co. The solute was Components: Original Measurements: ͑ ͒ 47 used without further puriﬁcation. 1 Benzoic acid, 4-hydroxy-, A.E. Beezer, S. Forster, W.-B. butyl ester; ͑n-butyl Park, and G.J. Rimmer, Estimated Errors: p-hydroxybenzoate; Thermochim. Acta 178,59 ͒ ͑ ͒ Solubility: nothing speciﬁed. butylparaben ;C11H14O3; 1991 . ͓ ͔ Temperature: precision Ϯ0.1 °C. 94-26-8 ͑ ͒ ͓ ͔ 2 Ethanol; C2H3O; 64-17-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: 3.2.3.3. Polyethylene glycol derivative T/K=288, 293, and 298 A. Goto and R. Goto

Solubility of butylparaben in water–ethanol mixtures Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 58F. Shihab, W. Shefﬁeld, J. Temperature Concentration of Solubility propyl ester ͑propyl Sprowls, and J. Nematollahi, J. T/K ethanol %a c /mol dm−3 p-hydroxybenzoate; Pharm. Sci. 59, 1574 ͑1970͒. 1 ͒ propylparaben ;C10H12O3; 288 0 7.04ϫ10−3 ͓ ͔ 94-13-3 95 3.21 ͑2͒ Poly͑oxy-1,1,2-ethanediyl͒, 293 0 8.35ϫ10−4 ␣-hydro-␻-hydroxy- 95 3.36 ͑polyethylene glycol 400; PEG ͒ ͑ ͒ 298 0 1.05ϫ10−4 400 ; C2H4O nH2O; ͓71767-64-1͔ 95 2.31 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 aNo speciﬁc information on mass or volume percent was stated in the original paper. Variables: Prepared by: Concentration of PEG 400 A. Goto and R. Goto Auxiliary Information t/ °C=27 Methods/Apparatus/Procedure: Solubility of ethylparaben in water–PEG 400 mixtures The measurement of solubility was similar to that described by A.E. Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35,350 ͑1983͒. Absorbance measurements were made at 258 nm. Temperature Concentration of PEG 400 Solubility

/ ␥ / −3 / −3 Source and Purity of Materials: t °C 100w2 1 gdm c1 mol dm The butylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great 27 0 0.400 0.0022 Britain͒ and was used as received. The purity was speciﬁed as Ͼ99.5%. 20 1.825 0.0101 Ethanol was of Anala R grade. 40 9.000 0.0499 Estimated Errors: 60 116.000 0.6437 Nothing speciﬁed. 80 362.500 2.0116 100 365.000 2.0255

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Variables: Prepared by: Components: Original Measurements: Concentration of sucrose A. Goto and R. Goto 59 ͑1͒ Benzoic acid, 4-hydroxy-, J. Rubino and E.K. Obeng, J. t/ °C=25 butyl ester ͑n-butyl Pharm. Sci. 80, 479 ͑1991͒. p-hydroxybenzoate; ͒ Solubility of butylparaben in water–sucrose mixtures butylparaben ;C11H14O3; ͓94-26-8͔ ͑2͒ 1,2-Propanediol ͑propylene Concentration of ͒ ͓ ͔ Temperature sucrose Solubilitya glycol ;C3H8O2; 57-55-6 ͑3͒ Water; H O; ͓7732-18-5͔ 2 ␥ / −3 2 / −3 1 gdm 10 c1 mol dm / ͑ ͒ ͑ ͒ Variables: Prepared by: t °C 100w1 compiler compiler Concentration of propylene A. Goto and R. Goto 25 0.0 0.145 7.47 glycol 7.5 0.149 7.67 t/ °C=27 18.5 0.150 7.72 31.5 0.153 7.88 Solubility of butylparaben in water–propylene glycol mixtures 41.5 0.150 7.72 63.5 0.153 7.88 Concentration of Temperature propylene glycol Solubility aIn the original paper, the solubility was given as milligrams of ester per milliliter of solution. 100x1 / ␸ ͑ ͒ t °C 2 −ln x1 compiler Auxiliary Information

27 0.00 10.45 0.002 89 Methods/Apparatus/Procedure: 0.10 9.95 0.004 77 The experimental detail is given in the compilation of Ref. 51 for the 0.20 9.43 0.008 03 methylparaben–sucrose–water system in Sec. 3.2.1.3. 0.30 8.70 0.016 7 Source and Purity of Materials: 0.40 7.68 0.046 2 Butylparaben was obtained from Eastman Kodak. The solute was used 0.50 6.43 0.161 without further puriﬁcation. 0.60 5.13 0.592 0.70 3.59 2.76 Estimated Errors: 0.80 2.50 8.21 Solubility: nothing speciﬁed. 0.90 1.90 15.0 Temperature: precision Ϯ0.1 °C. 1.00 1.76 17.2

Auxiliary Information 3.2.4.3. Organic salt Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 59 for the Components: Original Measurements: methylparaben–water system in Sec. 2.2.1.1. ͑1͒ Benzoic acid, 4-hydroxy-, 5A. Goto, F. Endo, and K. Ito, Source and Purity of Materials: butyl ester ͑butyl Chem. Pharm. Bull. 25,1165 ͑ ͒ Butylparaben of high purity was obtained from Eastman Chemical Co. 4-hydroxybenzoate; 1977 . ͒ and used as received from the supplier. The melting point was 68 °C and butylparaben ;C11H14O3; ͓ ͔ the value agreed with that reported in Ref. 46. 94-26-8 ͑2͒ Sulfuric acid monododecyl Estimated Errors: ester, sodium salt ͑sodium lauryl Solubility: the variation among triplicate samples was Ͻ5%. sulfate; sodium dodecyl sulfate͒; ͓ ͔ Temperature: Ϯ0.2 °C ͑the authors reported͒. C12H25O4SNa; 151-21-3 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: Concentration of sodium lauryl A. Goto 3.2.4.2. Carbohydrate sulfate t/ °C=27 Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 51A.N. Paruta and B.B. Sheth, J. Solubility of butylparaben in water–sodium lauryl sulfate mixture butyl ester ͑butyl Pharm. Sci. 55, 1208 ͑1966͒. p-hydroxybenzoate; Temperature Concentration of sodium lauryl sulfate Solubility ͒ butylparaben ;C11H14O3; / 3 / −3 3 / −3 ͓94-26-8͔ t °C 10 c2 mol dm 10 c1 mol dm ͑2͒ ␣-D-Glucopyranoside, ␤-D-fructofuranosy ͑sucrose; 27 0 1.1 ͒ ͓ ͔ 40 24.3 sugar ;C12H22O11; 57-50-1 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

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Auxiliary Information Variables: Prepared by: Concentration of PEG 400 A. Goto, R. Goto, and H. Methods/Apparatus/Procedure: t/ °C=27 Miyamoto The experimental detail is given in the compilation of Ref. 5 for the ethylparaben–sodium lauryl sulfate–water system in Sec. 3.2.2.3. Solubility of butylparaben in water–PEG 400 mixtures Source and Purity of Materials: The detail is given in the compilation of Ref. 5 for the ethylparaben– Temperature Concentration of PEG 400 Solubility sodium lauryl sulfate–water system in Sec. 3.2.2.3. / ␥ / −3 / −3 t °C 100w2 1 gdm c1 mol dm Estimated Errors: 27 0 0.240 0.0012 Solubility: nothing speciﬁed. 20 1.313 0.0068 Temperature: precision Ϯ0.1 °C. 40 7.750 0.0399 60 207.500 1.0683a 80 610.000 3.1406 100 612.000 3.1514

aConcentration of butylparaben at a point just prior to separation into two 3.2.4.4. Polyethylene glycol derivatives phases. Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 4-hydroxy-, 58F. Shihab, W. Shefﬁeld, J. All procedures were identical to those given in the compilation of Ref. 58 1-butyl ester ͑n-butyl Sprowls, and J. Nematollahi, J. for the methylparaben–PEG 400–water system in Sec. 3.2.1.4. p-hydroxybenzoate; Pharm. Sci. 59, 1574 ͑1970͒. ͒ butylparaben ;C11H14O3; Source and Purity of Materials: ͓94-26-8͔ All the compounds were analytical grade. Butylparaben was obtained from ͑2͒ Poly͑oxy-1,1,2-ethanediyl͒, Matheson Coleman & Bell. Polyethylene glycol 400 was supplied by City ␣-hydro-␻-hydroxy- Chemical Corp. ͑polyethylene glycol 400; PEG ͒ ͑ ͒ 400 ; C2H4O nH2O; Estimated Errors: ͓ ͔ 71767-64-1 Solubility: nothing speciﬁed. ͑3͒ Water; H O; ͓7732-18-5͔ 2 Temperature: precision Ϯ0.1 °C.

Comment and/or Additional Data:

Temperature Concentration in phases Solubility in phases

Upper phase Lower phase Upper phase Lower phase T/K / ͑ ͒ / a / a / a / a t °C compiler Solvent %w v 100w1 %w v 100w1 %w v 100w2 %w v 100w2

27 303.2 PEG 43.39 42.13 40.53 38.66 1.25 1.21 54.31 51.94 Water 58.16 56.66 9.92 9.40 aIn the original paper, these concentration units were used by the author.

Solubility of butylparaben in water–PEG 1000 mixtures Components: Original Measurements: 42 ͑1͒ Benzoic acid, 4-hydrdoxy-, T.C. Corby and P.H. Elworthy, Temperature Concentration of PEG 1000a Solubility 1-butyl ester ͑n-butyl J. Pharm. Pharmacol. 23, Suppl, ͑ ͒ / / / −1 p-hydroxybenzoate; 39S 1971 . t °C %w v m1 mmol kg ͒ butylparaben ;C11H14O3; ͓94-26-8͔ 20 0 1.065 ͑2͒ Poly͑oxy-1,2-ethanediyl͒, 10 2.54 ␣-hydro-␻-hydroxy- 30 11.0 ͑polyethylene glycol 1000; PEG 40 22.1 ͒ ͑ ͒ 1000 ; C2H4O nH2O; ͓25322-68-3͔ aIn the original paper, %w/v was given as the concentration units. ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: Concentration of PEG 1000 A. Goto and R. Goto t/ °C=20

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Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 4-hydrdoxy-, 42T.C. Corby and P.H. Elworthy, The solubility was determined as described by P.H. Elworthy and F.J. 1-butyl ether ͑n-butyl J. Pharm. Pharmacol. 23, Suppl, Lipscomb, J. Pharm. Pharmacol. 20, 790 ͑1968͒. The solution was assayed p-hydroxybenzoate; 39S ͑1971͒. ͒ by ultraviolet spectroscopy. butylparaben ;C11H14O3; ͓94-26-8͔ Source and Purity of Materials: ͑2͒ Polyethylene glycol 1000 Butylparaben ͑BDH Ltd., Lab. reagent͒ was recrystallized from a monocetyl ether ͑cetomacrogol ethanol–water mixture and dried overnight at 40 °C in a vacuum over 1000͒; ͑ ͒ ͑ ͒ ͑ phosphorous pentaoxide. PEG of BDH Laboratory Reagent was used as CH3 CH2 mO CH2 nCH2OH; m received. =15or17,n=19to23͒; ͓͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Estimated Errors: Nothing speciﬁed. Variables: Prepared by: Concentration of cetomacrogol A. Goto and R. Goto 1000 t/ °C=20 Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydrdoxy-, 42T.C. Corby and P.H. Elworthy, 1-butyl ester ͑n-butyl J. Pharm. Pharmacol. 23, Suppl, Solubility of butylparaben in water–cetomacrogol 1000 mixtures p-hydroxybenzoate; 39S ͑1971͒. ͒ a butylparaben ;C11H14O3; Temperature Concentration of cetomacrogol 1000 Solubility ͓94-26-8͔ / / / −1 ͑2͒ t °C %w v m1 mmol kg 3,6,9,12,15-Pentaoxaheptadecane-1,17-diol ͑hexaoxyethylene glycol; 20 0 1.065 ͒ ͓ ͔ 1 1.35 hexagol ;C12H26O7; 2615-15-8 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 558.3 10 121 Variables: Prepared by: a / Concentration of hexagol A. Goto and R. Goto In the original paper, %w v was given as the concentration units. t/ °C=20 Auxiliary Information

Solubility of butylparaben in water–hexagol mixtures Methods/Apparatus/Procedure: Saturation solubilities of the solid compound were determined as Temperature Concentration of hexagola Solubility described by P.H. Elworthy and F.J. Lipscomb, J. Pharm. Pharmacol. 20, 790 ͑1968͒. Solubility was determined by a spectrophotometer. / / / −1 t °C %w v m1 mmol kg Source and Purity of Materials: 20 0 1.065 Butylparaben ͑BDH Ltd. Lab. reagent͒ was recrystallized from distilled 10 1.96 ethanol–water and dried overnight at 40 °C in a vacuum over ͑ ͒ 40 8.02 phosphorous pentaoxide. Cetomacrogol 1000 B.P.C. Macarthy’s Ltd. was used as received. The number of oxyethylene units was 21.5 and the aIn the original paper, %w/v was given as the concentration units. molecular weight was taken as 1210.

Auxiliary Information Estimated Errors: Nothing speciﬁed. Methods/Apparatus/Procedure: Saturation solubilities of the solid compound were determined as described by P.H. Elworthy and F.J. Lipscomb, J. Pharm. Pharmacol. 20, ͑ ͒ 790 1968 . Solubility was determined by a spectrophotometer. 3.2.5. Alkylparabens Source and Purity of Materials: Butylparaben ͑BDH Ltd., Lab. reagent͒ was recrystallized from distilled water and dried overnight at 40 °C in a vacuum over phosphorous 3.2.5.1. Alcohol pentaoxide. Hexagol was prepared by the method of P.H. Elworthy and C.B. Macfarlane, J. Chem. Soc. 1963, 907. Components: Original Measurements: ͑ ͒ 47 Estimated Errors: 1 Benzoic acid, 4-hydroxy-, A.E. Beezer, S. Forster, W.-B. 2-methylpropyl ester; ͑isobutyl Park, and G.J. Rimmer, Solubility: the standard error was Ϯ0.06 mmol kg−1. p-hydroxybenzoate; Thermochim. Acta 178,59 ͒ ͑ ͒ isobutylparaben ;C11H14O3; 1991 . ͓4247-02-3͔ ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: T/K=288, 293, and 298 A. Goto and R. Goto

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Solubility of isobutylparaben in water–ethanol mixtures Estimated Errors: Nothing speciﬁed. Temperature Concentration of Solubility / a / −3 T K ethanol % c1 mol dm

288 95 3.10 Components: Original Measurements: ͑ ͒ 47 293 95 3.29 1 Benzoic acid, 4-hydroxy-, A.E. Beezer, S. Forster, W.-B. heptyl ester; ͑heptyl Park, and G.J. Rimmer, 298 95 4.32 p-hydroxybenzoate; Thermochim. Acta 178,59 ͒ ͑ ͒ aNo specific information on mass or volume percent was stated in the origi- heptylparaben ;C14H20O3; 1991 . ͓1085-12-7͔ nal paper. ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ Auxiliary Information 3 Water; H2O; 7732-18-5 Variables: Prepared by: Methods/Apparatus/Procedure: T/K=288, 293, and 298 A. Goto and R. Goto The measurement of solubility was similar to that described by A.E. Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35, 350 ͑ ͒ 1983 . Absorbance measurements were made at 258 nm. Solubility of heptylparaben in water–ethanol mixtures Source and Purity of Materials: Temperature Concentration of Solubility The isobutylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, T/K ethanol %a c /mol dm−3 Great Britain͒ and was used as received. The purity was specified as 1 Ͼ 99.5%. Ethanol was of Anala R grade. 288 0 2.01ϫ10−4 95 3.29 Estimated Errors: 293 0 2.52ϫ10−4 Nothing specified. 95 3.79 298 0 2.63ϫ10−4 95 4.14 Components: Original Measurements: ͑ ͒ 47 a 1 Benzoic acid, 4-hydroxy-, A.E. Beezer, S. Forster, W.-B. No specific information on mass or volume percent was stated in the origi- ͑ hexyl ester; hexyl Park, and G.J. Rimmer, nal paper. p-hydroxybenzoate; Thermochim. Acta 178,59 ͒ ͑ ͒ hexylparaben ;C13H18O3; 1991 . Auxiliary Information ͓1083-27-8͔ ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 Methods/Apparatus/Procedure: ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 The measurement of solubility was similar to that described by A.E. Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35,350 Variables: Prepared by: ͑1983͒. Absorbance measurements were made at 258 nm. T/K=288, 293, and 298 A. Goto and R. Goto Source and Purity of Materials: The heptylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great Solubility of hexylparaben in water–ethanol mixtures Britain͒ and was used as received. The purity was specified as Ͼ99.5%. Temperature Concentration of Solubility Ethanol was of Anala R grade. T/K ethanol %a c /mol dm−3 1 Estimated Errors: 288 0 3.68ϫ10−4 Nothing specified. 95 3.16 293 0 3.81ϫ10−4 95 3.50 Components: Original Measurements: 298 0 6.19ϫ10−4 ͑1͒ Benzoic acid, 4-hydroxy-, 47A.E. Beezer, S. Forster, W.-B. 95 3.95 octyl ester; ͑octyl Park, and G.J. Rimmer, p-hydroxybenzoate; Thermochim. Acta 178,59 a ͒ ͑ ͒ No specific information on mass or volume percent was stated in the origi- octylparaben ;C15H22O3; 1991 . ͓ ͔ nal paper. 5153-25-3 ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ Auxiliary Information 3 Water; H2O; 7732-18-5

Source and Purity of Materials: The hexylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great Britain͒ and was used as received. The purity was speciﬁed as Ͼ99.5%. Ethanol was of Anala R grade.

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Solubility of octylparaben in water–ethanol mixtures Source and Purity of Materials: The decylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great Temperature Concentration of Solubility Britain͒ and was used as received. The purity was speciﬁed as Ͼ99.5%. / a / −3 T K ethanol % c1 mol dm Ethanol was of Anala R grade.

288 0 1.47ϫ10−4 Estimated Errors: 95 3.00 Nothing speciﬁed. 293 0 2.30ϫ10−4 95 3.07 298 0 4.65ϫ10−4 Components: Original Measurements: 95 3.16 ͑1͒ Benzoic acid, 4-hydroxy-, 47A.E. Beezer, S. Forster, W.-B. dodecyl ester ͑dodecyl Park, and G.J. Rimmer, aNo speciﬁc information on mass or volume percent was stated in the origi- p-hydroxybenzoate; Thermochim. Acta 178,59 ͒ ͑ ͒ nal paper. dodecylparaben ;C19H30O3; 1991 . ͓2664-60-0͔ ͑ ͒ ͓ ͔ Auxiliary Information 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Methods/Apparatus/Procedure: Variables: Prepared by: The measurement of solubility was similar to that described by A.E. T/K=288, 293, and 298 A. Goto and R. Goto Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35, 350 ͑1983͒. Absorbance measurements were made at 258 nm. Solubility of dodecylparaben in water–ethanol mixture Source and Purity of Materials: The octylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great Temperature Concentration of Solubility / a / −3 Britain͒ and was used as received. The purity was specified as Ͼ99.5%. T K ethanol % c1 mol dm Ethanol was of Anala R grade. 288 95 2.30 Estimated Errors: 293 95 2.40 Nothing specified. 298 95 2.49 aNo specific information on mass or volume percent was stated in the original paper. Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 47A.E. Beezer, S. Forster, W.-B. Auxiliary Information decyl ester; ͑decyl Park, and G.J. Rimmer, Methods/Apparatus/Procedure: p-hydroxybenzoate; Thermochim. Acta 178,59 ͒ ͑ ͒ The measurement of solubility was similar to that described by A.E. decylparaben ;C17H26O3; 1991 . ͓69679-30-7͔ Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35,350 ͑ ͒ ͓ ͔ ͑1983͒. Absorbance measurements were made at 258 nm. 2 Ethanol; C2H6O; 64-17-5 ͑3͒ Water; H O; ͓7732-18-5͔ 2 Source and Purity of Materials: Variables: Prepared by: The dodecylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, ͒ T/K=288, 293, and 298 A. Goto and R. Goto Great Britain and was used as received. The purity was specified as Ͼ99.5%. Ethanol was of Anala R grade.

Solubility of decylparaben in water–ethanol mixtures Estimated Errors: Nothing speciﬁed. Temperature Concentration of Solubility / a / −3 T K ethanol % c1 mol dm

288 0 3.20ϫ10−5 95 1.66 3.2.6. Benzylparaben 293 0 3.71ϫ10−4 95 1.66 298 0 8.80ϫ10−4 3.2.6.1. Alcohol 95 2.15 Components: Original Measurements: aNo speciﬁc information on mass or volume percent was stated in the origi- ͑1͒ Benzoic acid, 4-hydroxy-, 47A.E. Beezer, S. Forster, W.-B. nal paper. phenylmethyl ester; ͑benzyl Park, and G.J. Rimmer, p-hydroxybenzoate; Thermochim. Acta 178,59 Auxiliary Information ͒ ͑ ͒ benzylparaben ;C14H12O3; 1991 . ͓ ͔ Methods/Apparatus/Procedure: 94-18-8 ͑2͒ Ethanol; C H O; ͓64-17-5͔ The measurement of solubility was similar to that described by A.E. 2 6 ͑3͒ Water; H O; ͓7732-18-5͔ Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35, 350 2 ͑ ͒ 1983 . Absorbance measurements were made at 258 nm. Variables: Prepared by: T/K=288, 293, and 298 A. Goto and R. Goto

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Solubility of benzylparaben in water–ethanol mixtures Auxiliary Information

Temperature Concentration of Solubility Methods/Apparatus/Procedure: / a / −3 T K ethanol % c1 mol dm The experimental detail is given in the compilation of Ref. 51 for the methylparaben–sucrose–water system in Sec. 3.2.1.3. 288 95 1.41 293 95 1.79 Source and Purity of Materials: 298 95 2.39 Benzylparaben was obtained from Heyden Chem. Co. The solute was used without further purification. aNo specific information on mass or volume percent was stated in the original paper. Estimated Errors: Solubility: nothing specified. Auxiliary Information Temperature: precision Ϯ0.1 °C. Methods/Apparatus/Procedure: The measurement of solubility was similar to that described by A.E. Beezer, W.H. Hunter, and D.E. Storey, J. Pharm. Pharmacol. 35, 350 ͑1983͒. Absorbance measurements were made at 258 nm.

Source and Purity of Materials: 3.2.7. 2-Hydroxybenzoic acid salts The benzylparaben was the gift of Apin Chemicals Ltd. ͑Abingdon, Great Britain͒ and was used as received. The purity was speciﬁed as Ͼ99.5%. Ethanol was of Anala R grade.

Estimated Errors: Nothing speciﬁed. 3.2.7.1. Alcohol

Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy-, 25A. Seidell, J. Am. Chem. Soc. sodium salt ͑sodium salicylate͒; 31, 1164 ͑1909͒. ͓ ͔ C7H5ONa; 54-21-7 3.2.6.2. Carbohydrate ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Components: Original Measurements: Variables: Prepared by: ͑ ͒ 51 1 Benzoic acid, 4-hydroxy-, A.N. Paruta and B.B. Sheth, J. Concentration of ethanol A. Goto and H. Miyamoto ͑ ͑ ͒ phenylmethyl ester benzyl Pharm. Sci. 55, 1208 1966 . t/ °C=25 p-hydroxybenzoate; ͒ benzylparaben ;C14H13O3; ͓94-18-8͔ Solubility of sodium salicylate in water–ethanol mixtures ͑2͒ ␣-D-Glucopyranoside, ␤-D-fructofuranosy ͑sucrose; Concentration ͒ ͓ ͔ sugar ;C12H22O11; 57-50-1 Temperature of ethanol Solubility ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 / −1 100x2 100x1 m1 mol kg / ͑ ͒ ͑ ͒ ͑ ͒ Variables: Prepared by: t °C 100w2 compiler 100w1 compiler compiler Concentration of sucrose A. Goto and R. Goto t/ °C=25 25 0 0.00 53.6 11.0 0.722 10 4.16 52.1 11.5 0.679 20 8.91 50.2 11.4 0.630 Solubility of benzylparaben in water–sucrose mixtures 30 14.4 48.0 11.3 0.577 Concentration of 40 20.7 45.5 11.0 0.521 Temperature sucrose Solubilitya 50 28.1 42.2 10.6 0.456 60 37.0 38.4 9.95 0.389 ␥ / −3 2 / −3 1 gdm 10 c1 mol dm 70 47.7 33.0 8.81 0.307 / ͑ ͒ ͑ ͒ t °C 100w1 compiler compiler 80 61.0 25.0 6.82 0.208 90 77.9 15.0 4.20 0.110 25 0.0 0.092 4.03 92.3 82.4 12.0 3.39 0.0852 7.5 0.116 5.08 100 100 3.82 1.13 0.0248 18.5 0.131 5.74 31.5 0.140 6.13 41.5 0.143 6.27 46.0 0.149 6.53 63.5 0.153 6.70 aIn the original paper, the solubility was given as milligrams of ester per milliliters of solution.

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Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Benzoic acid, 2-hydroxy-, 25A. Seidell, J. Am. Chem. Soc. Saturation of the solutions was effected by moderate agitation of the ammonium salt ͑ammonium 31, 1164 ͑1909͒. ͒ mixtures of solute and solvent enclosed in tubes immersed in a salicylate ;C7H5O3H4N; constant-temperature water bath maintained at 25 °C. The attainment of ͓528-94-9͔ ͑ ͒ ͓ ͔ equilibrium was insured by analyzing solutions shaken for different 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ lengths of time. The dissolved material was determined usually by 3 Water; H2O; 7732-18-5 evaporation and weighing the residues after carefully drying at room temperature in vacuum desiccators. Variables: Prepared by: Concentration of ethanol A. Goto and H. Miyamoto Source and Purity of Materials: t/ °C=25 Sodium salicylate was recrystallized and dried.

Estimated Errors: Solubility of ammonium salicylate in water–ethanol mixtures Nothing speciﬁed. Concentration Temperature of ethanol Solubility

/ −1 Components: Original Measurements: 100x2 100x1 m1 mol kg ͑ ͒ 25 / ͑ ͒ ͑ ͒ ͑ ͒ 1 Benzoic acid, 2-hydroxy-, A. Seidell, J. Am. Chem. Soc. t °C 100w2 compiler 100w1 compiler compiler monolithium salt ͑lithium 31, 1164 ͑1909͒. ͒ ͓ ͔ salicylate ;C7H5LiO3; 552-38-5 25 0 0.00 50.8 10.7 6.65 ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 20 8.91 50.3 11.8 6.52 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 40 20.7 48.3 12.5 6.02 50 28.1 46.7 12.76 5.65 Variables: Prepared by: 60 37.0 42.0 12.78 4.67 Concentration of ethanol A. Goto and H. Miyamoto 80 61.0 38.0 12.2 3.95 t/ °C=25 85 68.9 35.0 11.5 3.47 90 77.9 31.6 10.6 2.98 Solubility of lithium salicylate in water–ethanol mixtures 92.3 82.4 30.0 10.2 2.76 95 88.1 27.8 9.59 2.48 Concentration 100 100 22.3 7.85 1.85 Temperature of ethanol Solubility

/ −1 100x2 100x1 m1 mol kg Auxiliary Information / ͑ ͒ ͑ ͒ ͑ ͒ t °C 100w2 compiler 100w1 compiler compiler Methods/Apparatus/Procedure: 25 0 0.00 56.0 13.7 8.83 The experimental detail is given in the compilation of Ref. 25 for the 10 4.16 55.9 14.4 8.80 sodium salicylate–ethanol–water system. 20 8.91 55.4 15.0 8.62 30 14.4 54.5 15.5 8.31 Source and Purity of Materials: 40 20.7 53.7 16.9 8.05 The ammonium salicylate sample was practically neutral to litmus paper H OHCOONH calculated from ammonia 50 28.1 52.5 16.6 7.67 and contained 98.7% C6 4 4 determination made by the Kjeldahl method. 60 37.0 51.1 17.1 7.25 70 47.7 49.5 17.6 6.80 Estimated Errors: 80 61.0 47.5 18.1 6.28 Nothing speciﬁed. 90 77.9 45.8 19.0 5.87 92.3 82.4 45.0 18.9 5.68 100 100 48.2 22.9 6.46 Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy-, 25A. Seidell, J. Am. Chem. Soc. Auxiliary Information strontium salt ͑strontium 31, 1164 ͑1909͒. ͒ salicylate ;C14H10O6Sr; Methods/Apparatus/Procedure: ͓526-26-1͔ ͑ ͒ ͓ ͔ The experimental detail is given in the compilation of Ref. 25 for the 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ sodium salicylate–ethanol–water system. 3 Water; H2O; 7732-18-5

Source and Purity of Materials: Variables: Prepared by: The recrystallized lithium salicylate sample contained, when analyzed by Concentration of ethanol A. Goto and H. Miyamoto / the United States Pharmacopoeia method, 95.5% C6H4OHCOOLi. t °C=25

Estimated Errors: Nothing speciﬁed.

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Solubility of strontium salicylate in water–ethanol mixtures Auxiliary Information

Concentration Methods/Apparatus/Procedure: Temperature of ethanol Solubility The experimental detail is given in the compilation of Ref. 25 for the sodium salicylate–ethanol–water system. / −1 100x2 100x1 m1 mol kg / ͑ ͒ ͑ ͒ ͑ ͒ t °C 100w2 compiler 100w1 compiler compiler Source and Purity of Materials: The strontium salicylate samples were analyzed by the United States 25 0 0.00 5.04 0.264 0.147 Pharmacopoeia method and contained 99.04% and 99.55% ͑ ͒ 10 4.16 4.88 0.271 0.142 C6H4OHCOO 2Sr+2H2O, respectively. 20 8.91 5.22 0.311 0.152 30 14.4 6.20 0.401 0.183 Estimated Errors: 40 20.7 7.70 0.546 0.231 Nothing speciﬁed. 50 28.1 8.08 0.625 0.243 60 37.0 7.15 0.600 0.213 70 47.7 5.90 0.541 0.173 Components: Original Measurements: ͑ ͒ 31 80 61.0 4.40 0.445 0.127 1 Benzoic acid, 2-hydroxy-, J.O. Halford, J. Am. Chem. silver salt ͑sliver salicylate͒; Soc. 55, 2272 ͑1933͒. 90 77.9 2.56 0.289 0.0726 ͓ ͔ C7H5O3Ag; 528-95-8 92.3 82.4 2.02 0.234 0.0570 ͑ ͒ ͓ ͔ 2 Ethanol; C2H6O; 64-17-5 100 100 0.44 0.056 0.0122 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: Concentration of ethanol A. Goto and H. Miyamoto t/ °C=25

Solubility of silver salicylate in water–ethanol mixtures

Concentration Temperature of ethanol Solubility

Average 3 / −3 100x2 Undersaturation Supersaturation 10 c1 mol dm / ͑ ͒ 3 / −3 3 / −3 ͑ ͒ t °C 100w2 compiler 10 c1 mol dm 10 c1 mol dm compiler

25 0 0 4.18 4.18 4.18 18.8 6.85 3.86 4.01 3.94 37.5 19.0 4.83 4.75 4.79 56.2 33.5 4.43 4.40 4.42 75.0 54.0 2.60 2.61 2.61 93.8 85.5 0.80 0.80 0.80

Auxiliary Information Components: Original Measurements: Methods/Apparatus/Procedure: ͑1͒ Salicylic acid, basic bismuth 25A. Seidell, J. Am. Chem. Soc. The saturated solutions were obtained by shaking an excess of silver salt salt ͑bismuth salicylate, basic; 31, 1164 ͑1909͒. with the solvent for 24 h in a thermostat at 25 °C. Both the bismuth subsalicylate͒; ͓ ͔ undersaturation and the supersaturation methods were performed to C7H5O4Bi; 14882-18-9 ͑ ͒ ͓ ͔ approach the equilibrium. The concentration in the saturated solution was 2 Ethanol; C2H6O; 64-17-5 ͑ ͒ ͓ ͔ determined by titration with sodium chloride, standardized against silver 3 Water; H2O; 7732-18-5 nitrate, to an end-point with the silver electrode. Variables: Prepared by: Source and Purity of Materials: Concentration of ethanol A. Goto and H. Miyamoto Silver salicylate was prepared by precipitation from solution of sodium t/ °C=25 salicylate. The obtained silver salicylate was washed with water, then with alcohol.

Estimated Errors: Solubility: nothing speciﬁed. Temperature: precision Ϯ0.05 °C.

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Solubility of bismuth salicylate in water–ethanol mixtures Auxiliary Information

Temperature Concentration of ethanol Solubility Methods/Apparatus/Procedure: The concentration of salicylic acid was determined by titration of sodium / −1 100x2 100x1 m1 mol kg hydroxide in an atmosphere free from carbon dioxide, using phenol red as / ͑ ͒ ͑ ͒ ͑ ͒ t °C 100w2 compiler 100w1 compiler compiler indicator ͓M. Kilpatrick, Jr. and E.F. Chase, J. Am. Chem. Soc. 53, 1732 ͑1931͒; E.F. Chase and M. Kilpatrick, Jr., J. Am. Chem. Soc. 53, 2589 25 0 0.00 0.01 0.000 50 0.28 ͑1931͒; A. Osol and M. Kilpatrick, Jr., J. Am. Chem. Soc. 55,4430 20 8.91 0.015 0.000 85 0.41 ͑1933͔͒. The temperature was indicated by E.F. Chase and M. Kilpatrick, 40 20.7 0.022 0.001 4 0.61 Jr., J. Am. Chem. Soc. 53, 2589 ͑1931͒. 60 37.0 0.036 0.002 8 0.99 80 61.0 0.065 0.006 3 1.8 Source and Purity of Materials: 90 77.9 0.095 0.010 2.6 Salicylic acid was puriﬁed by recrystallization. The melting point was 159 °C. 92.3 82.4 0.105 0.011 9 2.85 100 100 0.160 0.020 8 4.43 Estimated Errors: Nothing speciﬁed. Auxiliary Information

Methods/Apparatus/Procedure: Components: Original Measurements: The experimental detail is given in the compilation of Ref. 25 for the ͑1͒ Benzoic acid, 2-hydroxy- 23Fr. Hoffmann and K. Langbeck, sodium salicylate–ethanol–water system. ͑o-hydroxybenzoic acid; salicylic Z. Phys. Chem. 51,385͑1905͒. acid͒;CH O ; ͓69-72-7͔ Source and Purity of Materials: 7 6 3 ͑2͒ Sodium chloride; NaCl; No information given was given. ͓7647-14-5͔ ͑ ͒ ͓ ͔ Estimated Errors: 3 Water; H2O; 7732-18-5 Nothing speciﬁed. Variables: Prepared by: Concentration of NaCl E. Königsberger and L.-C. t/ °C=24.89 and 34.82 Königsberger

Solubility of salicylic acid in water–NaCl mixtures

3.3. Hydroxybenzoic acid–water–inorganic Concentration Solubility compound systems Temperature of NaCl Solubilitya change 2 / −1 3.3.1. Salicylic acid 10 m1 mol kg t/ °C 102x m /mol kg−1 104x ͑compiler͒ %b 3.3.1.1. Inorganic salts 2 2 1 24.89 0 0 2.8851 1.602 100.00 Components: Original Measurements: 0.036 06 0.020 025 2.9110 1.617 100.89 ͑1͒ Benzoic acid, 2-hydroxy- 35A. Osol and M. Kilpatrick, J. 0.045 043 0.025 012 2.9183 1.621 101.15 ͑o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 55, 4440 0.059 975 0.033 313 2.9324 1.629 101.64 ͒ ͓ ͔ ͑ ͒ 0.089 968 0.049 988 2.9176 1.622 101.13 acid ;C7H6O3; 69-72-7 1933 . ͑2͒ Lithium chloride; LiCl; 0.179 64 0.099 90 2.9027 1.615 100.61 ͓7447-41-8͔ 0.448 19 0.249 91 2.8149 1.570 97.57 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 0.879 72 0.492 66 2.6128 1.464 90.56 1.302 3 0.732 46 2.4236 1.363 84.00 Variables: Prepared by: 1.719 9 0.971 38 2.2487 1.270 77.94 Concentration of LiCl A. Goto, R. Goto, and H. 34.82 0 0 4.1844 2.324 100.00 t/ °C=25.15 Miyamoto 0.036 08 0.020 041 4.2062 2.337 100.52 0.045 12 0.025 062 4.2103 2.339 100.63 Solubility of salicylic acid in water–LiCl mixtures 0.060 14 0.033 407 4.2169 2.343 100.78 0.089 88 0.049 942 4.2127 2.342 100.68 Temperature Concentration of LiCl Density Solubility 0.179 98 0.100 10 4.1806 2.326 99.91 0.448 14 0.249 91 4.0196 2.242 96.06 t/ °C c /mol dm−3 ␳/gcm−3 102c /mol dm−3 2 1 0.894 34 0.500 98 3.7171 2.083 88.83 25.15 0.00 — 1.598 1.337 2 0.752 40 3.4398 1.936 82.20 0.5 1.010 1.194 1.779 7 1.005 8 3.1596 1.786 75.51 0.673 1.014 1.104 a ͑ / ͒/͑ 1.198 1.025 0.882 The molality solubility was calculated from the equation m1 = x1 M3 1 ͒ 2.067 1.047 0.607 −x1 −x2 . bWith respect to pure water.

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Auxiliary Information Variables: Prepared by: Concentration of NaCl A. Goto, R. Goto, and H. Methods/Apparatus/Procedure: t/ °C=25.15 Miyamoto The experimental detail is given in the compilation of Ref. 23 for the salicylic acid–ethanol–water system in Sec. 3.1.1.2. Solubility of salicylic acid in water–NaCl mixtures Source and Purity of Materials: Salicylic acid ͑Kahlbaum͒ was recrystallized repeatedly from water and Temperature Concentration of NaCl Density Solubility then from ethanol, m.p. 156 °C. Sodium chloride was of the best quality / / −3 ␳/ −3 2 / −3 ͑Kahlbaum͒ and further puriﬁed by precipitation from saturated solution t °C c2 mol dm gcm 10 c1 mol dm with hydrochloric acid. 25.15 0.00 — 1.598 Estimated Errors: 0.2 1.005 1.326 Solubility: nothing speciﬁed. 0.5 1.018 1.188 Temperature: precision Ϯ0.03 K. 1.0 1.039 0.984 2.0 1.076 0.666

Components: Original Measurements: Auxiliary Information ͑1͒ Benzoic acid, 2-hydroxy- 18S.S. Doosaj and W.V. Bhagwat, ͑o-hydroxybenzoic acid; salicylic J. Indian Chem. Soc. 10,225 Methods/Apparatus/Procedure: ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 The experimental detail is given in the compilation of Ref. 35 for the ͑2͒ Sodium chloride; NaCl; 19W.V. Bhagwat and S.S. Doosaj, salicylic acid–LiCl–water system. ͓7647-14-5͔ J. Indian Chem. Soc. 10,477 ͑ ͒ ͓ ͔ ͑ ͒ Source and Purity of Materials: 3 Water; H2O; 7732-18-5 1933 . Salicylic acid was puriﬁed by recrystallization. The melting point was Variables: Prepared by: 159 °C. Concentration of NaCl A. Goto, R. Goto, and H. t/ °C=25 Miyamoto Estimated Errors: Nothing speciﬁed.

Solubility of salicylic acid in water–NaCl mixtures

a Components: Original Measurements: Temperature Concentration of NaCl Solubility ͑1͒ Benzoic acid, 2-hydroxy- 33P. A. Ongley, J. Chem. Soc. / −3 2 / −3 ͑ c2 mol dm 10 c1 mol dm o-hydroxybenzoic acid; salicylic 1954, 3634. / ␥ / −3 ͑ ͒ ␥ / −3 ͑ ͒ ͒ ͓ ͔ t °C 2 gdm compiler 1 gdm compiler acid ;C7H6O3; 69-72-7 ͑2͒ Sodium chloride; NaCl; 25 0 0 2.478 1.794 ͓7647-14-5͔ ͑ ͒ ͓ ͔ 1.176 0.020 12 2.229 1.614 3 Water; H2O; 7732-18-5 5.88 0.100 6 2.219 1.607 Variables: Prepared by: 11.76 0.201 2 2.150 1.557 t/ °C=25 A. Goto, R. Goto, and H. 14.70 0.251 5 2.125 1.538 Miyamoto 19.60 0.335 4 2.075 1.502 29.40 0.503 1 2.000 1.448 39.20 0.670 7 1.901 1.376 Solubility of salicylic acid in water–NaCl mixture 58.80 1.006 1.719 1.245 Temperature Concentration of NaCl Solubility a ␥ ␥ In the original data, the values 1 and 2 were given as g/l of solution. 2 / −3 10 c1 mol dm Auxiliary Information / / −3 a ͑ ͒ t °C c2 mol dm pS compiler

Methods/Apparatus/Procedure: 25 0 1.793 1.611 No information was given. 1 1.991 1.021

Source and Purity of Materials: apS is the negative logarithm of the concentration in the saturated solutions No information was given. in moles/l.

Estimated Errors: Auxiliary Information Nothing speciﬁed. Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 33 for the salicylic acid–sodium benzoate–water system in Sec. 3.1.1.4. Components: Original Measurements: 35 ͑1͒ Benzoic acid, 2-hydroxy- A. Osol and M. Kilpatrick, J. Source and Purity of Materials: ͑ o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 55, 4440 The acid was either of AnalaR standard or was recrystallized before use. ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 . No information of the purity of sodium salts was reported. ͑2͒ Sodium chloride; NaCl; ͓7647-14-5͔ Estimated Errors: ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Nothing speciﬁed.

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Components: Original Measurements: Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 23Fr. Hoffmann and K. Langbeck, ͑1͒ Benzoic acid, 2-hydroxy- 35A. Osol and M. Kilpatrick, J. ͑o-hydroxybenzoic acid; salicylic Z. Phys. Chem. 51,385͑1905͒. ͑o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 55,4440 ͒ ͓ ͔ ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 acid ;C7H6O3; 69-72-7 1933 . ͑2͒ Potassium chloride; KCl; ͑2͒ Potassium chloride; KCl; ͓7447-40-7͔ ͓7447-40-7͔ ͑ ͒ ͓ ͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 3 Water; H2O; 7732-18-5

Variables: Prepared by: Variables: Prepared by: Concentration of KCl E. Königsberger and L.-C. Concentration of KCl A. Goto, R. Goto, and H. t/ °C=24.89 and 34.82 Königsberger t/ °C=25.15 Miyamoto

Solubility of salicylic acid in water–KCl mixtures Solubility of salicylic acid in water–KCl mixtures

Solubility Temperature Concentration of KCl Density Solubility Temperature Concentration of KCl Solubilitya change / / −3 ␳/ −3 2 / −3 t °C c2 mol dm gcm 10 c1 mol dm 2 / −1 10 m1 mol kg / 2 / −1 4 ͑ ͒ b 25.15 0.0 — 1.598 t °C 10 x2 m2 mol kg 10 x1 compiler % 0.2 1.008 1.353 24.89 0 0 2.8851 1.602 100.00 0.5 1.021 1.252 0.036 06 0.020 024 2.9216 1.623 101.26 1.0 1.042 1.096 0.045 06 0.025 027 2.9278 1.626 101.48 1.5 1.064 0.945 0.060 10 0.033 305 2.9364 1.631 101.78 2.0 1.087 0.833 0.089 99 0.050 001 2.9364 1.632 101.78 0.179 8 0.099 987 2.9377 1.634 101.82 Auxiliary Information 0.447 0 0.249 24 2.8831 1.608 99.70 0.877 7 0.491 54 2.6321 1.474 95.53 Methods/Apparatus/Procedure: 1.332 2 0.749 49 2.6131 1.471 90.57 The experimental detail is given in the compilation of Ref. 35 for the 1.776 0 1.003 60 2.4759 1.400 85.82 salicylic acid–LiCl–water system. 34.82 0 0 4.1844 2.324 100.00 0.036 08 0.020 042 4.2206 2.345 100.87 Source and Purity of Materials: 0.045 12 0.025 061 4.2263 2.348 101.00 Salicylic acid was purified by recrystallization. The melting point was 0.060 10 0.033 378 4.2337 2.353 101.18 159 °C. 0.090 24 0.050 144 4.2325 2.353 101.15 Estimated Errors: 0.179 95 0.100 05 4.2203 2.348 100.86 Nothing specified. 0.450 32 0.251 13 4.1277 2.303 98.65 0.882 82 0.494 47 3.9268 2.200 93.85 1.340 7 0.754 44 3.7075 2.087 88.60 Components: Original Measurements: 1.777 8 1.004 8 3.5003 1.976 83.65 ͑1͒ Benzoic acid, 2-hydroxy- 35A. Osol and M. Kilpatrick, J. ͑ aThe molality solubility was calculated from the equation m =͑x /M ͒/͑1 o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 55,4440 1 1 3 ͒ ͓ ͔ ͑ ͒ ͒ acid ;C7H6O3; 69-72-7 1933 . −x1 −x2 . ͑ ͒ b 2 Potassium bromide; KBr; With respect to pure water. ͓7758-02-3͔ ͑3͒ Water; H O; ͓7732-18-5͔ Auxiliary Information 2 Variables: Prepared by: Methods/Apparatus/Procedure: Concentration of KBr A. Goto and H. Miyamoto / The experimental detail is given in the compilation of Ref. 23 for the t °C=25.15 salicylic acid–ethanol–water system in Sec. 3.1.1.2. Solubility of salicylic acid in water–KBr mixtures Source and Purity of Materials: Salicylic acid ͑Kahlbaum͒ was recrystallized repeatedly from water and Temperature Concentration of KBr Density Solubility then from ethanol. The melting point of salicylic acid was m.p. 156 °C. Potassium chloride was of the best quality ͑Kahlbaum͒ and further / / −3 ␳/ −3 2 / −3 t °C c2 mol dm gcm 10 c1 mol dm purified by chlorination, evaporation and recrystallization. 25.15 0.0 1.598 Estimated Errors: 0.2 1.014 1.381 Solubility: nothing specified. 0.5 1.038 1.308 Temperature: precision Ϯ0.03K. 1.0 1.080 1.185

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Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 35 for the The experimental detail is given in the compilation of Ref. 23 for the salicylic acid–LiCl–water system. salicylic acid–ethanol–water system in Sec. 3.1.1.2.

Source and Purity of Materials: Source and Purity of Materials: Salicylic acid was purified by recrystallization. The melting point was Salicylic acid ͑Kahlbaum͒ was recrystallized repeatedly from water and 159 °C. then from ethanol. The melting point of salicylic acid was 156 °C. Potassium nitrate was of the best quality ͑Kahlbaum͒ and further purified Estimated Errors: by recrystallization. Nothing specified. Estimated Errors: Solubility: nothing specified. Ϯ Components: Original Measurements: Temperature: precision 0.03 K. ͑1͒ Benzoic acid, 2-hydroxy- 23Fr. Hoffmann and K. Langbeck, ͑o-hydroxybenzoic acid; salicylic Z. Phys. Chem. 51,385͑1905͒. ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 Components: Original Measurements: ͑ ͒ 27 2 Potassium nitrate; KNO3; ͑1͒ Benzoic acid, 2-hydroxy- J. Kendall, Proc. R. Soc. ͓7757-79-1͔ ͑o-hydroxybenzoic acid; salicylic London Ser. A 85,200͑1911͒. ͑ ͒ ͓ ͔ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 acid ;C7H6O3; 69-72-7 ͑2͒ Hydrochloric acid; HCl; Variables: Prepared by: ͓7647-01-0͔ Concentration of KNO E. Königsberger and L.-C. ͑ ͒ ͓ ͔ 3 3 Water; H2O; 7732-28-5 t/ °C=24.89 and 34.82 Königsberger Variables: Prepared by: Concentration of HCl A. Goto and H. Miyamoto Solubility of salicylic acid in water–KNO mixtures 3 t/ °C=25

Concentration Solubility a Temperature of KNO3 Solubility change

2 / −1 10 m1 mol kg / 2 / −1 4 ͑ ͒ b t °C 10 x2 m2 mol kg 10 x1 compiler %

24.89 0 0 2.8851 1.602 100.00 0.036 08 0.020 029 2.9351 1.630 101.73 0.045 093 0.025 044 2.9433 1.635 102.02 0.059 847 0.033 241 2.9588 1.644 102.55 0.089 994 0.050 00 2.9776 1.655 103.20 0.180 47 0.100 36 3.0103 1.675 104.34 0.453 45 0.252 86 3.0672 1.711 106.31 0.901 92 0.502 53 3.1061 1.740 107.66 1.337 9 0.752 77 3.1198 1.756 108.13 1.776 6 1.004 0 3.1249 1.767 108.31 34.82 0 0 4.1844 2.324 100.00 0.036 08 0.020 036 4.2499 2.361 101.57 0.045 08 0.025 044 4.2548 2.364 101.68 0.059 84 0.033 241 4.2683 2.372 102.01 0.089 98 0.050 00 4.2874 2.383 102.46 0.180 55 0.100 42 4.3334 2.411 103.56 0.453 40 0.252 86 4.3855 2.447 104.81 0.899 04 0.503 66 4.4123 2.473 105.45 1.337 7 0.752 77 4.4007 2.477 105.17 1.776 4 1.004 0 4.3848 2.479 104.79

a ͑ / ͒/͑ The molality solubility was calculated from the equation m1 = x1 M3 1 ͒ −x1 −x2 . bwith respect to pure water.

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Solubility of salicylic acid in water–HCl mixtures

Concentration of Temperature HCl Solubilitya ͑Av.b =0.016 32 mol dm−3͒

2 / −3 10 c1 mol dm Original / / −3 ␥ / −3 t °C c2 mol dm data 1 gdm Gravimetric Volumetric

25 0.0000 0.0563 2.252 1.631 1.634 0.0179 — — — 1.290 0.0357 — — — 1.238 0.1250 0.0419 1.676 1.214 — 0.2500 0.0412 1.648 1.194 — 0.5000 0.0387 1.548 1.123 — aIn the original paper, the concentrations of HCl and salicylic acid were given as “Normality” units. In the original paper, the solubility was given as grams 3 ␥ / per 25 cm of the saturated solution. 1 =m1 V, where m1 is mass of 2-hydroxybenzoic acid and V is volume of the solution. The mass concentrations in the table were calculated by the compiler. b ͑ ␥ ͒ ͑ ͒ ͑ ͒ The average in pure water was calculated by the compiler from c1 calc. by using 1 , c1 gravimetric , and c1 volumetric .

Auxiliary Information Auxiliary Information

Methods/Apparatus/Procedure: Methods/Apparatus/Procedure: The experimental detail is given in the compilation of Ref. 27 for the The solubilities were determined at 25 °C, excess of the solid being salicylic acid–formic acid–water system in Sec. 3.1.1.3. shaken with solutions of hydrochloric acid of varying concentration in a thermostat for several days. After saturation, the clear solution was Source and Purity of Materials: analyzed both for dissolved and solvent acid. Solvent acid ͑hydrochloric Salicylic acid was recrystallized from freshly distilled water. acid͒ was determined gravimetrically, dissolved acids ͑salicylic acid͒ by direct weighing after evaporation in a vacuum over soda lime. The author Estimated Errors: stated that this method was used for most of the sparingly soluble acid in Solubility: precision 0.2%–0.4%. hydrochloric acid. Temperature: precision Ϯ0.1 °C. Source and Purity of Materials: No information was given.

Components: Original Measurements: Estimated Errors: ͑ ͒ 28 1 Benzoic acid, 2-hydroxy- J. Knox and M.B. Richards, J. Nothing speciﬁed. ͑o-hydroxybenzoic acid; salicylic Chem. Soc. 115, 508 ͑1919͒. ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 ͑2͒ Hydrochloric acid; HCl; ͓7647-01-0͔ Components: Original Measurements: ͑ ͒ ͓ ͔ ͑1͒ Benzoic acid, 2-hydroxy- 29J. Kendall and J.C. Andrews, J. 3 Water; H2O; 7732-18-5 ͑o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 43,1545 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1921 . Variables: Prepared by: ͑2͒ Hydrochloric acid; HCl; Concentration of HCl A. Goto, R. Goto, and H. ͓7647-01-0͔ t/ °C=25 Miyamoto ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5

Variables: Prepared by: Solubility of salicylic acid in water–HCl mixtures Concentration of HCl A. Goto, R. Goto, and H. t/ °C=25 Miyamoto Temperature Concentration of HCla Solubility

/ / −3 2 / −3 t °C c2 mol dm 10 c1 mol dm Solubility of salicylic acid in water–HCl mixtures

25 0.000 1.613 Temperature Concentration of HCla Solubility 1.459 0.982 / / −3 2 / −3 t °C c2 mol dm 10 c1 mol dm 3.057 0.822 4.374 0.715 25 0.0 1.62 6.164 0.654 0.500 1.12 7.311 0.666 1.180 1.01 7.311 0.710 1.848 0.912 8.730 0.794 2.498 0.834 3.308 0.777 10.20 0.856 4.410 0.732 aIn the original paper, the concentration of the acids was expressed in 7.172 0.695 9.522 0.721 equivalent normality. 11.73 0.768

aThe author used “normality units”.

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Auxiliary Information Solubility of salicylic acid in water–HNO3 mixtures

Methods/Apparatus/Procedure: a Temperature Concentration of HNO3 Solubility Standardized hydrochloric acid solutions were rotated with excess of / / −3 2 / −3 t °C c2 mol dm 10 c1 mol dm powdered solute in a thermostat until saturation was reached. Samples of the clear solutions were pipetted out into tared porcelain crucibles and 25 0.0 1.62 were allowed to reach constant weight in a desiccator at room 0.0109 1.49 temperature. 0.0420 1.40 0.0807 1.39 Source and Purity of Materials: 0.2409 1.41 Salicylic acid was puriﬁed by recrystallization from water. 0.5514 1.50 Estimated Errors: 1.019 1.84 Nothing speciﬁed. aThe author used “normality unit”.

Auxiliary Information Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 81H. Tomida, T. Yotsuyanagi, and Methods/Apparatus/Procedure: ͑o-hydroxybenzoic acid; salicylic K. Ikeda, Chem. Pharm. Bull. 26, Standardized nitric acid solutions were rotated with an excess of ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 2824 1978 . powdered solute in a thermostat until saturation was reached. Samples of ͑2͒ Hydrochloric acid; HCl; the clear solutions were pipetted out into tared porcelain crucibles and ͓7647-01-0͔ were allowed to reach constant weight in a desiccator at room ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 temperature.

Variables: Prepared by: Source and Purity of Materials: Concentration of HCl A. Goto and R. Goto Salicylic acid was puriﬁed by recrystallization from water. t/ °C=25 Estimated Errors: Nothing speciﬁed. Solubility of salicylic acid in water–HCl mixture

Temperature Concentration of HCl Solubility / / −3 2 / −3 Components: Original Measurements: t °C c2 mol dm 10 c1 mol dm ͑1͒ Benzoic acid, 2-hydroxy- 35A. Osol and M. Kilpatrick, J. 25 1.0 1.08 ͑o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 55,4440 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1933 . ͑ ͒ 2 Sodium perchlorate; NaClO4; Auxiliary Information ͓7601-89-9͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Methods/Apparatus/Procedure: An excess of salicylic acid was added to 10 ml volumes of aqueous Variables: Prepared by:

hydrochloric acid solution. The solution was shaken for 2 days at a Concentration of NaClO4 A. Goto, R. Goto, and H. constant temperature. After equilibration, sample solutions were pipetted t/ °C=25.15 Miyamoto through cotton ﬁlters. The samples were diluted with pH 7.0 phosphate buffer and assayed spectrophotometrically. Solubility of salicylic acid in water–NaClO4 mixtures Source and Purity of Materials: Salicylic acid was recrystallized from a water–ethanol mixture. Concentration of

Temperature NaClO4 Density Solubility Estimated Errors: / / −3 ␳/ −3 2 / −3 t °C c2 mol dm gcm 10 c1 mol dm Solubility: nothing speciﬁed. Temperature: precision Ϯ1°C. 25.15 0.00 1.598 0.472 1.034 1.400 0.500 1.038 1.396 Components: Original Measurements: 1.000 1.076 1.338 ͑1͒ Benzoic acid, 2-hydroxy- 29J. Kendall and J.C. Andrews, J. 1.103 1.082 1.332 ͑o-hydroxybenzoic acid; salicylic Am. Chem. Soc. 43, 1545 1.863 1.141 1.215 ͒ ͓ ͔ ͑ ͒ acid ;C7H6O3; 69-72-7 1921 . ͑2͒ Nitric acid; HNO ; 3 Auxiliary Information ͓7697-37-2͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Methods/Apparatus/Procedure: Variables: Prepared by: The experimental detail is given in the compilation of Ref. 35 for the salicylic acid–LiCl–water system. Concentration of HNO3 A. Goto, R. Goto, and H. / t °C=25 Miyamoto Source and Purity of Materials: Salicylic acid was puriﬁed by recrystallization. The melting point was 159 °C.

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Estimated Errors: Solubility of 3-hydroxybenzoic acid in water–KCl mixtures Nothing speciﬁed. Temperature Concentration of KCl Density Solubility / / −3 ␳/ −3 2 / −3 t °C c2 mol dm gcm 10 c1 mol dm

25.15 0.0 — 7.06 0.2 1.010 6.57 0.5 1.024 6.06 3.3.2. 3-Hydroxybenzoic acid 1.0 1.044 5.29 1.5 1.067 4.70 Components: Original Measurements: 2.0 1.088 3.99 ͑1͒ Benzoic acid, 3-hydroxy- 33P. A. Ongley, J. Chem. Soc. ͑m-hydroxybenzoic acid͒; 1954, 3634. Auxiliary Information ͓ ͔ C7H6O3; 99-06-9 ͑2͒ Sodium chloride; NaCl; Methods/Apparatus/Procedure: ͓7647-14-5͔ The experimental detail is given in the compilation of Ref. 35 for the ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 salicylic acid–LiCl–water system in Sec. 3.3.1.1.

Variables: Prepared by: Source and Purity of Materials: t/ °C=25 A. Goto, R. Goto, and H. 3-Hydroxybenzoic acid was puriﬁed by recrystallization. The melting Miyamoto point was 201 °C.

Estimated Errors: Solubility of 3-hydroxybenzoic acid in water–NaCl mixture Nothing speciﬁed.

Temperature Concentration of NaCl Solubility 2 / −3 10 c1 mol dm / / −3 a ͑ ͒ t °C c2 mol dm pS compiler

25 0 1.275 5.309 3.3.3. 4-Hydroxybenzoic acid 1 1.422 3.784

apS is the negative logarithm of the concentration in the saturated solutions Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy- 33P.A. Ongley, J. Chem. Soc. in moles/l. ͑p-hydroxybenzoic acid͒; 1954, 3634. ͓ ͔ Auxiliary Information C7H6O3; 99-96-7 ͑2͒ Sodium chloride; NaCl; Methods/Apparatus/Procedure: ͓7647-14-5͔ ͑ ͒ ͓ ͔ The experimental detail is given in the compilation of Ref. 33 for the 3 Water; H2O; 7732-18-5 salicylic acid–sodium benzoate–water system in Sec. 3.1.1.4. Variables: Prepared by: Source and Purity of Materials: t/ °C=25 A. Goto, R. Goto, and H. The acid was either of AnalaR standard or was recrystallized before use. Miyamoto No information on the purity of organic solvents was reported. Solubility of 4-hydroxybenzoic acid in water–NaCl mixture Estimated Errors: Nothing speciﬁed. Temperature Concentration of NaCl Solubility 2 / −3 10 c1 mol dm / / −3 a ͑ ͒ t °C c2 mol dm pS compiler Components: Original Measurements: ͑1͒ Benzoic acid, 3-hydroxy- 35A. Osol and M. Kilpatrick, J. 25 0 1.370 4.206 ͑m-hydroxybenzoic acid͒; Am. Chem. Soc. 55, 4440 1 1.530 2.951 C H O ; ͓99-06-9͔ ͑1933͒. 7 6 3 apS is the negative logarithm of the concentration in the saturated solutions ͑2͒ Potassium chloride, KCl; in moles/l. ͓7447-40-7͔ ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-5 Auxiliary Information

Variables: Prepared by: Methods/Apparatus/Procedure: Concentration of KCl A. Goto, R. Goto, and H. The experimental detail is given in the compilation of Ref. 33 for the / t °C=25.15 Miyamoto salicylic acid–sodium benzoate–water system in Sec. 3.1.1.4.

Source and Purity of Materials: The acid was either of AnalaR standard or was recrystallized before use. No information of the purity of organic solvents was reported.

Estimated Errors: Nothing speciﬁed

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Solubility of 4-hydroxybenzoic acid in water–HCl–dioxane mixtures Components: Original Measurements: 35 ͑1͒ Benzoic acid, 4-hydroxy- A. Osol and M. Kilpatrick, J. Volume fraction of ͑p-hydroxybenzoic acid͒; Am. Chem. Soc. 55, 4440 Temperature dioxane Solubility ͓ ͔ ͑ ͒ C7H6O3; 99-96-7 1933 . / ␸ / −3 t °C 3 x1 c1 mol dm ͑2͒ Potassium chloride; KCl; ͓7447-40-7͔ 25 0.0 0.000 60 0.0335 ͑ ͒ ͓ ͔ 3 Water; H2O; 7732-18-56 0.20 0.007 2 0.330 0.45 0.030 2 1.06 Variables: Prepared by: 0.50 0.047 8 1.45 Concentration of KCl A. Goto, R. Goto, and H. 0.55 0.058 5 1.64 t/ °C=25.15 Miyamoto 0.60 0.071 0 1.83 0.65 0.082 0 1.95 Solubility of 4-hydroxybenzoic acid in water–KCl mixtures 0.70 0.093 9 2.05 0.80 0.115 2.10 Temperature Concentration of KCl Density Solubility 0.85 0.121 2.02 t/ °C c /mol dm−3 ␳/gcm−3 102c /mol dm−3 2 1 0.90 0.127 1.89 25.15 0.0 — 4.51 0.95 0.122 1.62 0.2 1.009 4.30 1.00 0.084 4 0.968 0.5 1.023 3.99 0.7 1.030 3.81 Auxiliary Information 1.0 1.043 3.54 1.5 1.066 3.23 Methods/Apparatus/Procedure: 2.0 1.088 2.89 The solubility of the acid was determined in dioxane–HCl–water systems. The pH 2 hydrochloric aqueous solution was used alone or mixed with 2.5 1.109 2.56 dioxane. A suitable amount of dioxane, water or mixture was introduced into screw-capped vials containing an excess amount of solute. After Auxiliary Information being sealed with several turns of electrical tape, the vials were submerged in water at 25 °C and shaken at 100 cpm for 24 h in a Methods/Apparatus/Procedure: constant-temperature bath. After equilibrium had been attained, the The experimental detail is given in the compilation of Ref. 35 for the saturated solutions were transferred to a syringe and filtered by a filter of salicylic acid–LiCl–water system in Sec. 3.3.1.1. pore size Ͻ1 ␮m. The solutions were assayed using a spectrophotometer. The solubility of the solute was determined at least six times. Source and Purity of Materials: 4-Hydroxybenzoic acid was purified by recrystallization. The melting Source and Purity of Materials: point was 214 °C. 4-Hydroxybenzoic acid ͑Matheson Coleman Bell, Norwood, OH͒ was recrystallized from aqueous ethanol and dried at 105 °C overnight. Estimated Errors: A pure grade of dioxane ͑Mallinckrodt Chem. Works, St. Louis, MO͒ was Nothing specified. used as received.

Estimated Errors: Solubility: The experimental variation in solubility was Ͻ3% in replicate samples. Temperature: precision Ϯ0.1 °C. 4. Hydroxybenzoic Acids and Parabens in Multicomponent Aqueous Systems 4.1. Hydroxybenzoic acid–water–organic compound–inorganic compound systems 4.2. Hydroxybenzoic acid–water–inorganic compound 1 –inorganic compound 2 systems 4.1.1. 4-Hydroxybenzoic acid „ … „ … 4.2.1. 3-Hydroxybenzoic acid

Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy- 43P.L. Wu and A. Martin, J. Components: Original Measurements: ͑p-hydroxybenzoic acid͒; Pharm. Sci. 72, 587 ͑1983͒ ͑1͒ Benzoic acid, 3-hydroxy- 81H. Tomida, T. Yotsuyanagi, and ͓ ͔ 82 C7H6O3; 99-96-7 A. Martin, P.L. Wu, Z. Liron, ͑o-hydroxybenzoic acid͒; K. Ikeda, Chem. Pharm. Bull. 26, ͑ ͒ ͓ ͔ ͑ ͒ 2 Hydrochloric acid; HCl; and S. Cohen, J. Pharm. Sci. 74, C7H6O3; 99-06-9 2824 1978 . ͓7647-01-0͔ 638 ͑1985͒. ͑2͒ Hydrochloric acid; HCl; ͑ ͒ 3 1,4-Dioxane; C4H8O3; ͓7647-01-0͔ ͓123-91-1͔ ͑3͒ Potassium chloride; KCl; ͑ ͒ ͓ ͔ 4 Water; H2O; 7732-18-5 ͓7447-40-7͔ ͑ ͒ ͓ ͔ 4 Water; H2O; 7732-18-5 Variables: Prepared by: Concentration of dioxane A. Goto and R. Goto Variables: Prepared by: t/ °C=25 t/ °C=25 A. Goto and R. Goto

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Solubility of 3-hydroxybenzoic acid in water–HCl–KCl mixture. The 4.3. Hydroxybenzoic acid and buffer solution at pH=1.0 was used as a solvent. paraben–water–urea–inorganic compound systems Temperature Solubility 4.3.1. Salicylic acid / 2 / −3 t °C 10 c1 mol dm

25 5.71 Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 36D.M. Altwein, J.N. Delgado, ͑o-hydroxybenzoic acid; salicylic and F.P. Cosgrove, J. Pharm. Sci. Auxiliary Information ͒ ͓ ͔ ͑ ͒ acid ;C6H7O3; 69-72-7 54, 603 1965 . ͑ ͒ ͓ ͔ Methods/Apparatus/Procedure: 2 Urea; CH4N2O; 57-13-6 ͑3͒ Hydrochloric acid; HCl; An excess of 3-hydroxybenzoic acid was added to 10 ml volumes of pH ͓7647-01-0͔ 1.0 HCl–KCl buffer solution. The solution was shaken for 2 days at a ͑4͒ Water; H O; ͓7732-18-5͔ constant temperature. After equilibration, sample solutions were pipetted 2 through cotton ﬁlters. The samples were diluted with pH 7.0 phosphate Variables: Prepared by: buffer and assayed spectrophotometrically. Concentration of urea A. Goto and R. Goto / Source and Purity of Materials: t °C=25.5, 37.0 and 45.0 3-Hydroxybenzoic acid was recrystallized from a water–ethanol mixture. Solubility of salicylic acid in water–HCl–urea mixtures Estimated Errors: Solubility: nothing speciﬁed. Concentration Salicylic acid concentration Ϯ Temperature: precision 1°C Temperature of urea Solubility as complexa / 1 / −3 2 / −3 2 / −3 t °C 10 c2 mol dm 10 c1 mol dm 10 ccomplex mol dm

25.5 0.0 1.491 — 10.0 1.882 0.391 20.0 2.222 0.731 4.2.2. 4-Hydroxybenzoic acid 30.0 3.041 1.550 32.5 3.065 1.574 Components: Original Measurements: 35.0 3.135 1.644 ͑1͒ Benzoic acid, 4-hydroxy- 81H. Tomida, T. Yotsuyanagi, and 37.5 2.693 1.202 ͑p-hydroxybenzoic acid͒; K. Ikeda, Chem. Pharm. Bull. 26, 40.0 2.606 1.115 ͓ ͔ ͑ ͒ C7H6O3; 99-96-7 2824 1978 . 42.5 2.932 1.441 ͑ ͒ 2 Hydrochloric acid; HCl; 45.0 2.447 0.956 ͓7647-01-0͔ 50.0 2.534 1.043 ͑3͒ Potassium chloride; KCl; 60.0 2.461 0.970 ͓7447-40-7͔ ͑ ͒ ͓ ͔ 37.0 0.0 1.810 — 4 Water; H2O; 7732-18-5 10.0 2.389 0.579 Variables: Prepared by: 20.0 3.041 1.231 t/ °C=25 A. Goto and R. Goto 22.5 3.387 1.577 25.0 3.651 1.841 Solubility of 4-hydroxybenzoic acid in water–HCl–KCl mixture. The 27.5 4.235 2.425 buffer solution at pH 1.0 was used as a solvent. 30.0 4.402 2.592 32.5 4.651 2.841 Temperature Solubility 37.5 4.792 2.982 / 2 / −3 t °C 10 c1 mol dm 40.0 4.832 3.022 50.0 4.651 2.841 25 4.17 60.0 4.199 2.389 45.0 0.0 2.751 — Auxiliary Information 10.0 3.837 1.086 20.0 4.561 1.810 Methods/Apparatus/Procedure: 30.0 6.009 3.258 An excess of 4-hydroxybenzoic acid was added to 10 ml volumes of pH 40.0 7.511 4.726 1.0 HCl–KCl buffer solution. The solution was shaken for 2 days at a 50.0 7.456 4.705 constant temperature. After equilibration, sample solutions were pipetted 60.0 7.420 4.669 through cotton ﬁlters. The samples were diluted with pH 7.0 phosphate buffer and assayed spectrophotometrically. aSalicylic acid–urea complex is formed by the interaction of urea with sali- Source and Purity of Materials: cylic acid. 4-Hydroxybenzoic acid was recrystallized from a water–ethanol mixture.

Estimated Errors: Solubility: nothing speciﬁed. Temperature: precision Ϯ1°C.

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Auxiliary Information aIn the original paper, the solubility was given as milligrams of solute per milliliter of solution. Methods/Apparatus/Procedure: Definite quantities of salicylic acid ͑2 g at 25.5 and 37.0 °C, 2 and 2.5 g Auxiliary Information at 45.0 °C͒ and 50 ml portions of each solution ͑1–6 moldm−3 urea solution adjusted to 0.1 mol dm−3 ͓H+͔ with HCl͒ were placed in 100 ml Methods/Apparatus/Procedure: volumetric flasks. The flasks were stoppered and the mixtures shaken in a The solubility study was carried out according to Altewin’s method.36 thermostat for 12 h at 25.5, 37.0, and 45.0 °C. 1 ml volumetric pipettes Solutions of urea ranging from 0 to 3 mol dm−3 were prepared in 25 mm equipped with twine were used. Aliquot quantities were removed from the screw-cap culture tubes, by adding an appropriate amount of 3 mol dm−3 dissolution fluids, diluted to the proper concentration, and assayed urea solution and sufficient 0.1 mol dm−3 HCl to bring the total volume to spectrophotometrically for the amount of acid at 236 m␮. All samples and 10 ml. 0.6 g of salicylic acid was added to the tubes. The sample was controls were run in triplicate. equilibrated in a water bath shaker at temperatures of 30 and 45 °C and in a Gyrotory incubator shaker model G-25 at 37 °C for periods of not Source and Purity of Materials: less than 12 or more than 18 h. After allowing to settle, the liquid was Salicylic acid was of Baker analyzed reagent. Melting point of the acid filtered through a Millipore filter ͑0.45 ␮m pore size͒. 1 ml of sample was was 159 °C. withdrawn from the filtrate and was diluted to 10 ml with 0.1 mol dm−3 HCl acidified methanol. All subsequent dilutions were made with acidified Estimated Errors: methanol ͑1:10͒. The salicylic acid concentration was determined Solubility: nothing specified. spectrophotometrically. Temperature: precision Ϯ0.2 °C. Methods/Apparatus/Procedure: Salicylic acid ͑m.p. 159 °C͒ and urea ͑m.p. 132 °C͒ were of Fisher certified reagent grade. Components: Original Measurements: 83 ͑1͒ Benzoic acid, 2-hydroxy- S. Feldman and M. Gibaldi, J. Estimated Errors: ͑ ͑ ͒ o-hydroxybenzoic acid; salicylic Pharm. Sci. 56, 370 1967 . Nothing specified. ͒ ͓ ͔ acid ;C7H6O3; 69-72-7 ͑ ͒ ͓ ͔ 2 Urea; CH4N2O; 57-13-6 ͑3͒ Hydrochloric acid; HCl; ͓7647-01-0͔ Components: Original Measurements: ͑ ͒ ͓ ͔ ͑ ͒ 83 4 Water; H2O; 7732-18-5 1 Benzoic acid, 2-hydroxy- S. Feldman and M. Gibaldi, J. ͑o-hydroxybenzoic acid; salicylic Pharm. Sci. 56, 370 ͑1967͒. ͒ ͓ ͔ Variables: Prepared by: acid ;C7H6O3; 69-72-7 Concentration of urea A. Goto and R. Goto ͑2͒ Urea, methyl- ͑methylurea͒; / ͓ ͔ t °C=30, 37 and 45 C2H6N2O; 598-50-5 ͑3͒ Hydrochloric acid; HCl; ͓7647-01-0͔ Solubility of salicylic acid in water–HCl–urea mixtures ͑ ͒ ͓ ͔ 4 Water; H2O; 7732-18-5

Concentration of Concentration of Variables: Prepared by: a Temperature urea HCl Solubility Concentration of methylurea A. Goto and R. Goto t/ °C=30, 37, and 45 ␥ / −3 2 / −3 1 gdm 10 c1 mol dm / / −3 / −3 ͑ ͒ ͑ ͒ t °C c2 mol dm c3 mol dm compiler compiler Solubility of salicylic acid in water–HCl–methylurea mixtures 30 0.0 0.1 1.97 1.43 0.5 0.1 2.27 1.64 Concentration of Concentration 1.0 0.1 2.61 1.89 Temperature methylurea of HCl Solubilitya 1.5 0.1 2.86 2.07 ␥ / −3 2 / −3 2.0 0.1 3.32 2.40 1 gdm 10 c1 mol dm t/ °C c /mol mol−3 c /mol dm−3 ͑compiler͒ ͑compiler͒ 2.5 0.1 3.68 2.66 2 3 3.0 0.1 4.03 2.92 30 0.0 0.1 1.97 1.43 37 0.0 0.1 2.62 1.90 0.5 0.1 2.52 1.82 0.5 0.1 3.05 1.21 1.0 0.1 3.14 2.27 1.0 0.1 3.60 2.61 1.5 0.1 4.03 2.92 1.5 0.1 3.96 2.87 2.0 0.1 5.17 3.74 2.0 0.1 4.46 3.23 2.5 0.1 5.96 4.31 2.5 0.1 4.94 3.58 3.0 0.1 7.42 5.37 3.0 0.1 5.57 4.03 37 0.0 0.1 2.62 1.90 45 0 0.1 3.40 2.46 0.5 0.1 3.35 2.43 0.5 0.1 3.87 2.80 1.0 0.1 4.39 3.18 1.0 0.1 4.51 3.27 1.5 0.1 5.25 3.80 1.5 0.1 5.03 3.64 2.0 0.1 6.64 4.81 2.0 0.1 5.74 4.15 2.5 0.1 8.24 5.97 2.5 0.1 6.35 4.60 3.0 0.1 9.74 7.05 3.0 0.1 6.92 5.01

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Solubility of salicylic acid in water–HCl–methylurea mixtures Auxiliary Information

Concentration of Concentration Methods/Apparatus/Procedure: Temperature methylurea of HCl Solubilitya The experimental detail is given in the compilation of Ref. 83 for the salicylic acid–urea–hydrochloric acid–water system. ␥ / −3 2 / −3 1 gdm 10 c1 mol dm / / −3 / −3 ͑ ͒ ͑ ͒ t °C c2 mol mol c3 mol dm compiler compiler Source and Purity of Materials: Salicylic acid ͑m.p. 159 °C͒ was of Fisher certiﬁed reagent grade. 45 0 0.1 3.40 2.46 1,3-dimethylurea ͑m.p. 107 °C͒ was obtained from Eastman Kodak. The 0.5 0.1 4.46 3.23 purity of each reagent was determined by melting point analysis and 1.0 0.1 5.75 4.16 spectrophotometric method. 1.5 0.1 7.39 5.35 Estimated Errors: 2.0 0.1 8.92 6.46 Nothing speciﬁed. 2.5 0.1 11.21 8.116 3.0 0.1 13.46 9.745

a In the original paper, the solubility was given as milligrams of solute per 4.3.2. 3-Hydroxybenzoic acid milliliter of solution.

Auxiliary Information Components: Original Measurements: ͑ ͒ 36 Methods/Apparatus/Procedure: 1 Benzoic acid, 3-hydroxy- D.M. Altwein, J.N. Delgado, ͑m-hydroxybenzoic acid; and F.P. Cosgrove, J. Pharm. Sci. The experimental detail is given in the compilation of Ref. 83 for the ͓ ͔ ͑ ͒ C6H7O3; 99-06-9 54, 603 1965 . salicylic acid–urea–hydrochloric acid–water system. ͑ ͒ ͓ ͔ 2 Urea; CH4N2O; 57-13-6 ͑ ͒ Source and Purity of Materials: 3 Hydrochloric acid; HCl; ͓ ͔ Salicylic acid ͑m.p. 159 °C͒ and methylurea ͑m.p. 101 °C͒ were obtained 7646-01-0 ͑ ͒ ͓ ͔ from Fisher and Eastman Kodak, respectively. The purity of each reagent 4 Water; H2O; 7732-18-5 was determined by melting point analysis and spectrometric method. Variables: Prepared by: Estimated Errors: Concentration of urea A. Goto and R. Goto / Nothing speciﬁed. t °C=25.5, 37.0, and 45.0

Solubility of 3-hydroxybenzoic acid in water–HCl–urea mixtures Components: Original Measurements: ͑1͒ Benzoic acid, 2-hydroxy- 83S. Feldman and M. Gibaldi, J. Original ͑o-hydroxybenzoic acid; salicylic Pharm. Sci. 56, 370 ͑1967͒. concentration 3-Hydroxybenzoic acid ͒ ͓ ͔ Temperature of urea Solubility concentration as complex acid ;C7H6O3; 69-72-7 ͑2͒ Urea, 1,3-dimethyl / 1 / −3 2 / −3 2 / −3 ͑ ͒ t °C 10 c2 mol dm 10 c1 mol dm 10 ccomplex mol dm 1,3-dimethylurea ;C3H8N2O; ͓ ͔ 96-31-1 25.5 0.0 5.249 — ͑3͒ Hydrochloric acid; HCl; 10.0 6.877 1.628 ͓7647-01-0͔ ͑ ͒ ͓ ͔ 15.0 8.064 2.815 4 Water; H2O; 7732-18-5 20.0 8.687 3.438 Variables: Prepared by: 25.0 9.954 4.705 Concentration of A. Goto and R. Goto 30.0 10.316 5.067 1,3-dimethylurea 35.0 12.850 7.601 t/ °C=30 40.0 14.479 9.230 45.0 16.108 10.859 Solubility of salicylic acid in water–HCl–1,3-dimethylurea mixtures 50 18.714 13.465 60 21.718 16.469 Concentration of Concentration 37.0 0.0 10.135 — Temperature 1,3-dimethylurea of HCl Solubilitya 10.0 13.610 3.475 20.0 18.099 7.964 ␥ / −3 2 / −3 1 gdm 10 c1 mol dm 30.0 22.805 12.670 t/ °C c /mol dm−3 c /mol dm−3 ͑compiler͒ ͑compiler͒ 2 3 40.0 26.285 16.145 30 0.0 0.1 1.97 1.43 50.0 30.193 20.778 0.5 0.1 2.97 2.15 60.0 32.912 22.777 1.0 0.1 4.04 2.92 45.0 0.0 11.801 — 1.5 0.1 5.61 4.06 10.0 16.434 4.633 2.0 0.1 7.33 5.31 20.0 22.370 10.569 2.5 0.1 9.71 7.03 30.0 27.510 15.709 3.0 0.1 12.53 9.07 40.0 32.578 20.777 50.0 38.514 26.713 a In the original paper, the solubility was given as milligrams of solute per 60.0 44.885 33.084 milliliter of solution.

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Auxiliary Information Solubility of 4-hydroxybenzoic acid in water–HCl–urea mixtures

Methods/Apparatus/Procedure: Concentration 4-Hydroxybenzoic acid The experimental procedure was similar to that for salicylic acid. 3 g of Temperature of urea Solubility concentration as complex 3-hydroxybenzoic acid and 50 ml portions of each solution −3 −3 + / 1 / −3 2 / −3 2 / −3 ͑1–6 moldm urea solution adjusted to 0.1 mol dm ͓H ͔ with HCl͒ t °C 10 c2 mol dm 10 c1 mol dm 10 ccomplex mol dm were placed in 100 ml volumetric flasks. The flasks were stoppered and the mixtures shaken in a thermostat for 12 h. 1 ml volumetric pipets 45.0 0.0 12.814 — equipped with twine were used. Aliquot quantities were removed from the 10.0 18.135 5.321 dissolution fluids, diluted to the proper concentration, and assayed 20.0 22.081 9.267 spectrophotometrically for the amount of acid at 236 m␮. All samples and 30.0 27.148 14.334 controls were run in triplicate. 40.0 27.438 14.624 50.0 27.655 14.841 Source and Purity of Materials: 60.0 29.854 17.040 3-Hydroxybenzoic acid ͑Eastman Organic Chemicals͒ was used. The m.p. was 201 °C. Auxiliary Information Estimated Errors: Solubility: nothing specified. Methods/Apparatus/Procedure: Temperature: precision Ϯ0.2 °C. The experimental procedure was similar to that for salicylic acid. 2 g of 4-hydroxybenzoic acid and 50 ml portions of each solution ͑1–6 moldm−3 urea solution adjusted to 0.1 mol dm−3 ͓H+͔ with HCl͒ were placed in 100 ml volumetric flasks. The flasks were stoppered and 4.3.3. 4-Hydroxybenzoic acid the mixtures shaken in a thermostat for 12 h. 1 ml volumetric pipets equipped with twine were used. Aliquot quantities were removed from the dissolution fluids, diluted to the proper concentration, and assayed Components: Original Measurements: spectrophotometrically for the amount of acid at 254 m␮. All samples and ͑1͒ Benzoic acid, 4-hydroxy- 36D.M. Altwein, J.N. Delgado, controls were run in triplicate. ͑p-hydroxybenzoic acid͒; and F.P. Cosgrove, J. Pharm. Sci. ͓ ͔ ͑ ͒ Source and Purity of Materials: C6H7O3; 99-96-7 54,603 1965 . ͑ ͒ ͓ ͔ 4-Hydroxybenzoic acid of Eastman Organic Chemicals was used. The 2 Urea; CH4N2O; 57-13-6 ͑3͒ Hydrochloric acid; HCl; melting point was 214 °C. ͓7647-01-0͔ Estimated Errors: ͑4͒ Water; H O; ͓7732-18-55͔ 2 Solubility: nothing specified. Variables: Prepared by: Temperature: precision Ϯ0.2 °C. Concentration of urea A. Goto and R. Goto t/ °C=25.5, 37.0, and 45.0

Solubility of 4-hydroxybenzoic acid in water–HCl–urea mixtures

Concentration 4-Hydroxybenzoic acid 4.3.4. Methylparaben Temperature of urea Solubility concentration as complex

/ 1 / −3 2 / −3 2 / −3 t °C 10 c2 mol dm 10 c1 mol dm 10 ccomplex mol dm Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 84C. McDonald and R.E. 25.5 0.0 3.873 — methyl ester ͑methyl Lindstrom, J. Pharm. Pharmacol. 10.0 6.407 2.534 p-hydroxybenzoate; 26,39͑1974͒. 20.0 8.144 4.271 ͒ methylparaben ;C8H8O3; 30.0 9.448 5.575 ͓99-76-3͔ 40.0 10.570 6.697 ͑2͒ Sodium chloride; NaCl; 45.0 11.221 7.348 ͓7647-14-5͔ ͑ ͒ ͓ ͔ 50.0 11.942 8.069 3 Urea; CH4N2O; 57-13-6 ͑ ͒ ͓ ͔ 60.0 12.923 9.050 4 Water; H2O; 7732-18-5 37.0 0.0 7.457 — Variables: Prepared by: 10.0 11.583 4.126 Concentration of urea and A. Goto, R. Goto, and H. 15.0 13.465 6.008 sodium chloride Miyamoto 20.0 14.625 7.167 t/ °C=25 25.0 15.203 7.746 27.5 18.316 10.859 30.0 17.954 10.497 32.5 18.764 11.307 40.0 18.731 11.274 45.0 18.823 11.366 50.0 19.692 12.235 60.0 21.357 13.900

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Solubility of methylparaben in water–NaCl–urea mixtures 4.4. Hydroxybenzoic acid and paraben–water–urea–inorganic compound Temperature Concentration of NaCl Concentration of urea Solubility „1…–inorganic compound „2… systems / / −3 / −3 / −3 t °C c2 kmol m c3 kmol m c1 kmol m 4.4.1. 4-Hydroxybenzoic acid 25 0 0 0.0146 0 1 0.0197 Components: Original Measurements: 0 2 0.0242 ͑1͒ Benzoic acid, 4-hydroxy- 81H. Tomida, T. Yotsuyanagi, and 0 3 0.0296 ͑p-hydroxybenzoic acid͒; K. Ikeda, Chem. Pharm. Bull. 26, ͓ ͔ ͑ ͒ 0 4 0.0354 C7H6O3; 99-96-7 2824 1978 . 0 5 0.0413 ͑2͒ Hydrochloric acid; HCl; ͓ ͔ 25 1 0 0.0093 7647-01-0 ͑ ͒ 1 1 0.0128 3 Potassium chloride; KCl; ͓7447-40-7͔ 1 2 0.0164 ͑4͒ Water; H O; ͓7732-18-5͔ 1 3 0.0208 2 1 4 0.0258 Variables: Prepared by: 1 5 0.0312 t/ °C=25 A. Goto and H. Miyamoto 25 2 0 0.0062 2 1 0.0084 Solubility of 4-hydroxybenzoic acid in water–HCl–KCl mixturesa 2 2 0.0114 2 3 0.0143 Temperature Solubility 2 4 0.0187 / 2 / −3 2 5 0.0227 t °C 10 c1 mol dm 25 3 0 0.0038 25 4.17 3 1 0.0054 3 2 0.0076 aThe buffer solution at pH 1.0 was used as a solvent. 3 3 0.0100 3 4 0.0129 Auxiliary Information 3 5 0.0166 Methods/Apparatus/Procedure: An excess of 4-hydroxybenzoic acid was added to 10 ml volumes of pH Auxiliary Information 1.0 HCl–KCl buffer solution. The solution was shaken for 2 days at a constant temperature. After equilibration, sample solutions were pipetted Methods/Apparatus/Procedure: through cotton filters. The samples were diluted with pH 7.0 phosphate Solubilities of methylparaben were determined in water, in 1–5 mol dm−3 buffer and assayed spectrophotometrically. sodium chloride solutions, in 1–5 mol dm−3 urea solutions, and in 1–5 moldm−3 sodium chloride solutions containing 1–5 mol dm−3 urea, Source and Purity of Materials: respectively. Excess methylparaben was equilibrated with the solutions at 4-Hydroxybenzoic acid was recrystallized from a water–ethanol mixture. 25 °C for 24 h. Samples were taken, filtered, diluted with water, and concentrations were determined from ultraviolet absorption plots of Estimated Errors: standard solutions determined at 256.75 nm. The saturated solubility was Solubility: nothing specified. reached within 24 h. Temperature: precision Ϯ1°C.

Source and Purity of Materials: Sodium chloride Analar ͑BDH͒ was used without further puriﬁcation. Urea ͑Fisons͒ was recrystallized from absolute ethanol and dried. Methylparaben was used without further puriﬁcation.

Estimated Errors: 4.4.2. Methylparaben Solubility: the overall experimental error is approximately Ϯ2.5%. Ϯ Temperature: precision 0.1 °C. Components: Original Measurements: ͑1͒ Benzoic acid, 4-hydroxy-, 52G. Dempsey and P. Molyneux, methyl ester ͑methyl J. Chem. Soc. Faraday Trans. 88, p-hydroxybenzoate; 971 ͑1992͒. ͒ methylparaben ;C8H8O3; ͓99-76-3͔ ͑2͒ Phosphate, hydrogen sodium ͓ ͔ salt; Na2HPO3; 7558-59-4 ͑3͒ Phosphate, dihydrogen

monopotassium salt; KH2PO3; ͓13977-65-6͔ ͑ ͒ ͓ ͔ 4 Water; H2O; 7732-18-5

Variables: Prepared by: t/ °C=25 A. Goto and H. Miyamoto

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Solubility of methylparaben in water–Na2HPO3 –KH2PO3 mixture 4.4.4. Propylparaben

Temperature Solubilitya Components: Original Measurements: / 3 / −3 52 t °C 10 c1 mol dm ͑1͒ Benzoic acid, 4-hydroxy-, G. Dempsey and P. Molyneux, propyl ester ͑propyl J. Chem. Soc. Faraday Trans. 88, 25 16.0 p-hydroxybenzoate; 971 ͑1992͒. ͒ aThe species of the solute was the monoanion ͑94%͒ at pH 6. propylparaben ;C10H12O3; ͓94-13-3͔ Auxiliary Information ͑2͒ Phosphate, hydrogen sodium ͓ ͔ salt; Na2HPO3; 7558-79-4 Methods/Apparatus/Procedure: ͑3͒ Phosphate, dihydrogen

The solubilities of the cosolute in pH 6.0 Sorenson phosphate buffer in monopotassium salt; KH2PO3; the presence of urea were determined using the piston-ﬁlter tube method, ͓13977-65-6͔ ͑ ͒ ͓ ͔ which enable the dissolution, equilibration, and ﬁltration to be carried out 4 Water; H2O; 7732-18-5 in the same closed system. The tubes were equilibrated by shaking for 24 h at 25.0°C. A sample of the supernatant was diluted 100-fold and Variables: Prepared by: assayed by UV spectrophotometry. t/ °C=25 A. Goto and H. Miyamoto

Source and Purity of Materials: Solubility of propylparaben in water–Na HPO –KH PO mixture The urea was BDH Laboratory grade. The methylparaben was BDH 2 3 2 3 Laboratory grade and recrystallized once from water. Temperature Solubilitya Estimated Errors: t/ °C 103c /mol dm−3 Nothing speciﬁed. 1 25 1.99

4.4.3. Ethylparaben a The species of the solute was the monoanion ͑94%͒ at pH 6.

Auxiliary Information Components: Original Measurements: ͑ ͒ 52 1 Benzoic acid, 4-hydroxy-, G. Dempsey and P. Molyneux, Methods/Apparatus/Procedure: ethyl ester ͑ethyl J. Chem. Soc. Faraday Trans. 88, The solubility was determined by the same method as described in the p-hydroxybenzoate; 971 ͑1992͒. compilation of Ref. 52 for the methylparaben–phosphate hydrogen sodium ethylparaben͒;CH O ; 9 10 3 salt–phosphate dihydrogen potassium salt system in Sec. 4.4.2. ͓120-47-8͔ ͑ ͒ 2 Phosphate, hydrogen sodium Source and Purity of Materials: ͓ ͔ salt; Na2HPO3; 7558-79-4 The urea was BDH Laboratory grade. The propylparaben was BDH ͑ ͒ 3 Phosphate, dihydrogen Laboratory grade and recrystallized once from water. monopotassium salt; KH2PO3; ͓13977-65-6͔ Estimated Errors: ͑ ͒ ͓ ͔ 4 Water; H2O; 7732-18-5 Nothing speciﬁed. Variables: Prepared by: t/ °C=25 A. Goto and H. Miyamoto

Solubility of ethylparaben in water–Na2HPO3 –KH2PO3 mixture

Temperature Solubilitya 4.4.5. Butylparaben

t/ °C 103c /mol dm−3 1 Components: Original Measurements: 25 5.30 ͑1͒ Benzoic acid, 4-hydroxy-, 52G. Dempsey and P. Molyneux, butyl ester ͑butyl J. Chem. Soc. Faraday Trans. 88, a ͑ ͒ The species of the solute was the monoanion 94% at pH 6. p-hydroxybenzoate; 971 ͑1992͒. butylparaben͒;C H O ; Auxiliary Information 11 14 3 ͓94-26-8͔ ͑ ͒ Methods/Apparatus/Procedure: 2 Phosphate, hydrogen sodium salt; Na HPO ; ͓7558-79-4͔ The solubility was determined by the same method as described in the 2 3 ͑3͒ Phosphate, dihydrogen compilation of Ref. 52 for the methylparaben–phosphate hydrogen sodium monopotassium salt; KH PO ; salt–phosphate dihydrogen potassium salt system in Sec. 4.4.2. 2 3 ͓13977-65-6͔ ͑ ͒ ͓ ͔ Source and Purity of Materials: 4 Water; H2O; 7732-18-5 The urea was BDH Laboratory grade. The ethylparaben was BDH Variables: Prepared by: Laboratory grade and recrystallized once from water. t/ °C=25 A. Goto, R. Goto, and H. Estimated Errors: Miyamoto Nothing speciﬁed.

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34 ͑ ͒ Solubility of butylparaben in water–Na2HPO3 –KH2PO3 mixture N. A. Hall, Am. J. Pharm. 132, 406 1960 . 35 A. Osol and M. Kilpatrick, J. Am. Chem. Soc. 55, 4440 ͑1933͒. 36 Temperature Solubilitya D. M. Altwein, J. N. Delgado, and F. P. Cosgrove, J. Pharm. Sci. 54,603 ͑1965͒. / 3 / −3 37 ͑ ͒ t °C 10 c1 mol dm J. C. Philip, J. Chem. Soc. Trans. 87, 987 1905 . 38 P. G. Desai and A. M. Patel, J. Indian Chem. Soc. 12,131͑1935͒. 25 1.13 39 H. Nogami, T. Nagai, and K. Ito, Chem. Pharm. Bull. ͑Tokyo͒ 14,351 ͑1966͒. a ͑ ͒ The species of the solute was the monoanion 94% at pH 6. 40 A. N. Paruta, B. J. Sciarrone, and N. G. Lordi, J. Pharm. Sci. 53, 1349 ͑1964͒. Auxiliary Information 41 N. V. Sidgwick and E. K. Ewbank, J. Chem. Soc. 1921, 979. 42 T. C. Corby and P. H. Elworthy, J. Pharm. Pharmacol. 23,39S͑1971͒. Methods/Apparatus/Procedure: 43 P. L. Wu and A. Martin, J. Pharm. Sci. 72,587͑1983͒. The solubility was determined by the same method as described in the 44 A. Martin, P. L. Wu, and A. Beerbower, J. Pharm. Sci. 73,188͑1984͒. compilation of Ref. 52 for the methylparaben–phosphate hydrogen sodium 45 R. J. Prankerd, Int. J. Pharm. 84, 233 ͑1992͒. salt–phosphate dihydrogen potassium salt system in Sec. 4.4.2. 46 D. J. W. Grant, M. Mehdizadeh, A. H.-L. Chow, and J. E. Fairbrother, Int. J. Pharm. 18,25͑1984͒. Source and Purity of Materials: 47 E. Beezer, S. Forster, W.-B. Park, and G. J. Rimmer, Thermochim. Acta The urea was BDH Laboratory grade. The butylparaben was BDH 178,59͑1991͒. Laboratory grade and recrystallized once from water. 48 R. H. Manzo and A. A. Ahumada, J. Pharm. Sci. 79, 1109 ͑1990͒. 49 R. Huettenrauch and I. Keiner, Pharmazie 31, 489 ͑1976͒. Estimated Errors: 50 S. H. Yalkowsky and S. C. Valvani, J. Pharm. Sci. 69, 912 ͑1980͒. Nothing speciﬁed. 51 A. N. Paruta and B. B. Sheth, J. Pharm. Sci. 55, 1208 ͑1966͒. 52 G. Dempsey and P. Molyneux, J. Chem. Soc., Faraday Trans. 88,971 ͑1992͒. 5. References 53 F. Giordano, R. Bettini, C. Donini, A. 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