3,371,110 United States Patent Office Patented Feb. 27, 1968 1. 2 3,371,110 isions of these pores are such as to accept for adsorption (CATALYTC CONVERSION OF AROMATIC molecules of certain dimensions while rejecting those of CARBOXYLIC ACDS TO PHENOLS large dimensions, these materials have come to be known Eye A. Hamilton, Pitman, and Philip S. Landis, Wood as "molecular sieves' and are utilized in a variety of ways bEry, N.J., assignors to Mobil Oil Corporation, a cor 5 to take advantage of these properties. poration of New York The present invention, as aforesaid, involves the use No Drawing. Filed Jan. 29, 1964, Ser. No. 341,120. of such zeolitic materials (or isomorphs thereof) for the 17 Claims. (C. 260-476) purpose of catalytically converting aromatic carboxylic acids to phenols. More specifically, the present invention This invention relates to the catalytic conversion of aro O comprises the oxidation of an aromatic carboxylic acid matic carboxylic acids to phenols and, more particularly, to a corresponding ester of the carboxylic acid and the to such conversions involving the use of the novel catalytic subsequent hydrolysis of such ester to the desired phenolic materials. compound and the starting aromatic carboxylic acid, at As a result of the need for plentiful sources of phenolic least the oxidation reaction and preferably both the compounds, processes for the production of phenols uti 5 oxidation and the hydrolysis reactions taking place under lizing aromatic carboxylic acids as starting materials have reaction conditions in the presence of a solid, porous crys been developed. One such process involves the oxidation talline aluminosilicate catalyst or an isomorph thereof. of aromatic carboxylic acids to form the corresponding The starting materials of the present invention may esters of such acids and the subsequent conversion of such include any aromatic carboxylic acid. Such acid may con esters to the corresponding phenols through a hydrolysis tain either an aryl or a naphthyl nucleus (as exemplified, reaction, a by-product of the hydrolysis reaction being the for example, by benzoic acid, salicylic acid, tertiary butyl starting aromatic carboxylic acid. This process may be benzoic acids, toluic acids and naphthoic acids). Aromatic broadly represented by the following equations (wherein monocarboxylic acids containing biphenyl, bibenzyl or Ar represents an aryl radical): stilbene nuclei can also be converted to phenolic com (1) 2Ar COOH -- 1/2O2 - Air COO Air + H2O + CO2 25 pounds in accordance with the process of the present in (2) Air COO Air -- H2O - Air COOH - Aro H vention. The above process is ordinarily carried out in the pres Those acids found most useful in the carrying out of ence of a catalyst and, for practical purposes, prior art the process of the present invention are monocarboxylic investigators have restricted such catalyst to copper or to acids of the benzene series having at least one open posi a copper-containing material. 30 tion on the benzene ring adjacent to the point of attach In accordance with the present invention, it has now ment of the carboxyl group and in which any non-car been found that extremely advantageous results may be boxyl substituents are stable groups, such as phenyl, alkyl, obtained in the conversion of aromatic carboxylic acids to alkoxy, nitro, halogen, etc. Merely by way of example phenols using solid, porous crystalline aluminosilicates or of carboxylic acids which may be converted to phenols, isomorphs thereof. As will become apparent from the en 35 it is within the contemplation of the present invention suing description, while particularly advantageous results to convert benzoic acid to phenol; o-toluic acid to m are obtained with the use of copper-containing crystalline cresol; m-toluic acid to o- and p-cresol; p-toluic acid to aluminosilicate catalysts, the present invention is not so m-cresol; m-nitrobenzoic acid to p-nitrophenol; p-nitro restricted. benzoic acid to m-nitrophenol; p-chlorobenzoic acid to It is accordingly a primary object of the present inven 40 m-chlorophenol; p-methoxybenzoic acid to m-methoxy tion to provide a novel process for the conversion of aro phenol; p-phenylbenzoic acid to m-phenylphenol; 2,4-di matic carboxylic acids to phenols using solid, porous methylbenzoic acid to 3,5-dimethylphenol; etc. crystalline aluminosilicates or isomorphs thereof. Preferably, the starting aromatic carboxylic acid is it is another important object of the present invention utilized in liquid phase. Such acid may be liquefied either to provide a novel process for the conversion of aromatic 45 by melting it or by dissolving it in an inert medium such carboxylic acids to phenols involving the use of metal as water, benzene, toluene, xylene, biphenyl, phenyl ben cation-containing crystalline aluminosilicates or isomorphs zoate, hexachlorobutadiene, etc. Of the various organic thereof, preferred metal cations being copper, nickel and media which may be used for dissolving the acid, the pre uranium. ferred solvents are biphenyl for operations at or near at It is a further important object of the present invention mospheric pressure and toluene or benzene for operations to provide a novel method for synthesizing phenolic com at elevated pressures. pounds comprising oxidizing an aromatic carboxylic acid The aluminosilicates useable as catalysts in accordance to an ester thereof and subsequently hydrolyzing said with the present invention include a wide variety of posi ester to produce a phenolic compound and the initial aro tive ion-containing crystalline aluminosilicates, both matic carboxylic acid, at least the oxidation reaction tak 55 natural and synthetic. These aluminosilicates can be de ing place under oxidation reaction conditions in the pres scribed as a rigid three-dimensional network of SiO, ence of a solid, porous crystalline aluminosilicate or an and AlO4 tetrahedra in which the tetrahedra are cross isomorph thereof. linked by the sharing of oxygen atoms whereby the ratio These and further important objects and advantages of of the total aluminum and silicon atoms to oxygen atoms the present invention will become more apparent in con 30 is 1:2. The electrovalence of the tetrahedra containing nection with the following discussion and appended aluminum is balanced by the inclusion in the crystal of claims. a cation, for example, an alkali metal or an alkaline: Zeolitic materials, both natural and synthetic, in nat earth metl cation. This equilibrium cn be expressed by urally occurring and modified forms, have been demon formula wherein the ratio of Al to the number of the strated in the past to have catalytic capabilities for vari 85 various cations, such as Ca, Sr, Na2, K2 or Lia, is equal ous types of hydrocarbon conversion. Such zeolitic ma to unity. One cation may be exchanged either in entirety terials are ordered crystalline aluminosilicates having a or partially by another cation utilizing ion exchange definite crystalline structure within which there are a techniques as discussed hereinbelow. By means of such large number of small cavities which are interconnected 70 cation exchange, it is sometimes possible, or even de by a number of still smaller channels. These cavities and sirable, to vary the size of the pores in the given alumino channels are precisely uniform in size. Since the dimen silicate by suitable selection of the particular cation. The 3,371,110 3 4. spaces between the tetrahedra are occupied by molecules 0.9–-0.2Na2O: Al2O3 : wSiO2:yHO (VIII) of water prior to dehydration. wherein w is from 2.45 to 3.65, and y, in the hydrated A description of zeolites of the type useable in the form, is about 7. present invention is found in Patent 2,971,824, whose The formula for Zeolite S in terms of oxide mole ratios disclosure is hereby incorporated herein by reference. may be written as: These aluminosilicates have well-defined intra-crystalline dimensions such that only reactant or product molecules of suitable size and shape may be transported in either wherein w is from 4.6 to 5.9 and y, in the hydrated form, direction between the exterior phase and the interior of is about 6 to 7. the crystalline zeolite. O The formula for Zeolite T in terms of oxide mole ratios In their hydrated form, the aluminosilicates may be may be written as: represented by the formula: wherein M is a cation which balances the electrovalence wherein x is any value from about 0.1 to about 0.8 and of the tetrahedra, in represents the valence of the cation, y is any value from about 0 to about 8. w the moles of SiO2, and y the moles of HO, the removal The formula for Zeolite Z in terms of oxide mole ratios of which produces the characteristic open network system. may be written as: The cation may be any one or more of a number of posi (XI) tive ions as aforesaid, such ions being discussed in greater 20 detail hereinafter. The parent zeolite is dehydrated to wherein y is any value not exceeding 3. actuate it for use as a catalyst. Although the proportions The formula for Zeolite E in terms of oxide mole ratios of inorganic oxides in the silicates and their spatial ar may be written as: rangement may vary, effecting distinct properties in the 0.9-0.1M/nO: AlO:1.95+0.1SiO:yHaO (XII) aluminosilicates, the main characteristic of these materials is their ability to undergo dehydration without substan wherein M is a metal cation, n is the valence of the cation, tially affecting the SiO4 and AlO4 framework. In this re and y is a value of 0 to 4. spect, this characteristic is essential for obtaining catalyst The formula for Zeolite F in terms of oxide mole ratios compositions of high activity in accordance with the may be written as: invention. 30 Representative materials include a synthetic faujasite, 0.95-0.15M/no: AlO:2.05-0.3SiO3:yHO (XIII) designated Zeolite X, which can be represented in terms wherein M is a metal cation, n is the valence of the cation, of mole ratios of oxides as follows: and y is any value from 0 to about 3. 1.0-0.2M2/nO:Al2O3:2.5-0.5SiO:yHO (II) The formula for Zeolite Q, expressed in terms of oxide mole ratios, may be written as: wherein M is a metal cation having a valence of not more than three, in represents the valence of M, and y is a value 0.95+0.05MO:Al2O3:2.2-0.05SiO3:yH2O (XIV) up to eight depending on the identity of M and degree of wherein M is a metal cation, n is the valence of the cation, hydration of the crystal. The sodium form may be repre andy is any value from 0 to 5. sented in terms of mole ratios of oxides as follows: 40 The formula for Zeolite B may be written in terms of 0.9Na2O: AlO3:2.5SiO2:6.1HO (III) oxide mole ratios as: Another synthesized crystalline aluminosilicate, desig nated Zeolite A, can be represented in mole ratios of 1.0+0.2MO: AlO3:3.5-1.5SiO3:yH2O (XV) oxides as: wherein M represents a metal cation, n is the valence of the cation, and y has an average value of 5.1 but may 1.0-0.2M2/no: Al2O3:1.85–0.5SiO:yHO (IV) range from 0 to 6. wherein M represents a metal cation, n is the valence of Other synthesized crystalline aluminosilicates include M, and y is any value up to about 6. As usually prepared, those designated as ZK-4 and ZK-5. Zeolite A contains primarily sodium cations and is desig ZK-4 can be represented in terms of mole ratios of nated sodium Zeolite A. 50 Other suitable synthesized crystalline aluminosilicates oxides as: are those designated Zeolite Y, L and D. 0.1 to 0.3R: 0.7 to 1.0MO: The formula for Zeolite Y (which is a synthetic fau AlO3:2.5 to 4.0SiO2:yHO (XVI) jasite) expressed in oxide mole ratios is: 5 5 wherein R is a member selected from the group consist 0.9-0.2Na2O: AlO :wSiO2:yHO (V) ing of methylammonium oxide, hydrogen oxide and mix wherein w is a value ranging from 3 to 6 and y may be tures thereof with one another, M is a metal cation, n is any value up to about 9. the valence of the cation, and y is any value from about The composition of Zeolite L in oxide mole ratios may 3.5 to about 5.5. As usually synthesized, Zeolite ZK-4 60 contains primarily sodium cations and can be represented be represented as: by unit cell formula: 1.0-0.1M2/nC):Al2O3:6.4-0.5SiO:yHO (VI) (XVII) wherein M designates a metal cation, in represents the 7.5-2Na:2-0.5H:9-2AlO: 15-c2SiO2 valence of M, and y is any value from 0 to 7. The major lines of the X-ray diffraction pattern of The formula for Zeolite D, in terms of oxide mole ratios, ZK-4 are set forth in Table 1 below: amay be represented as: TABLE 1. wherein v is a value of 0 to 1, w is from 4.5 to about d value of reflection in A : 100 I/I 4.9 and y, in the fully hydrated form, is about 7. 12.00 ------100 Other synthetic crystalline aluminosilicates which can 9.12 ------29 be used include those designated as Zeolite R, S, T, Z, E, 8.578 ------73 F, Q and B. 7.035 ------52 The formula for Zeolite R in terms of oxide mole ratios 6.358 ------15 may be written as follows: 5.426 ------23 5 3,371,110 TABLE 1-Continued d value of reflection in A: 100 I/I by treatment with silver oxide or barium hydroxide. The 4262------11 reaction may be illustrated as follows: 4.062 ------49 N 3.662 ------65 cí? SoH, 3.39 ------30 -- 2C3I -} CH, CH, CH 3.254 ------41 N 1 2.950 ------54 N 2.725 ------10 2,663 ------7 (XVIII) 2.593 ------15 O 2.81 ------2 (Hil (H.OH 2.435 ------1. CH CE CH CH2 CE CH 2.341 ------2 h --2AgOH, -} -- 2AgI 2,225 ------2 E. By CH og By CH 2.159 ------4 2,121 ------5 CH CEOBI 2.085 ------2 (XIX) (XX) 2.061 ------2 2.033 ------5 20 In using the N,N'-dimethyltriethylenediammonium hy 1.90 ------2 droxide compound in the preparation of ZK-5, the hy 1880 ------2 droxide may be employed per se, or further treated with 1828 ------1. a source of silica, such as silica gel, and thereafter re 1813 ------1. acted with aqueous sodium aluminate in a reaction mix 1759 ------1. 25 ture whose chemical composition corresponds to the 1735 ------above-noted oxide mole ratios. Upon heating at tempera 1.720 ------5 tures of about 200 to 600 C., the methyl ammonium 1.703 ------1 ion is converted to hydrogen ion. 1669 ------2 Quite obviously, the above-listed molecular sieves are 1610 ------1. 30 only representative of the synthetic crystalline alumino 1.581 ------2 silicate molecular sieve catalysts which may be used in ac 1559 ------1. cordance with the process of the present invention, the ZK-4 can be prepared by preparing an aqueous solution particular enumeration of such sieves not being intended of oxides containing Na2O, Al2O3, SiO2, H2O and tetra to be exclusive. methyl-ammonium ion having a composition, in terms of At the present time, two commercially available molec oxide mole ratios, which falls within the following ular sieves are those of the “A” series and of the “X” ranges: series. A synthetic zeolite known as "Molecular Sieve 4A' is a crystalline sodium aluminosilicate having an effective SiO/Al2O3 2.5 to 11 pore diameter of about 4 angstroms. In the hydrated 40 NaO form, this material is chemically characterized by the 0.5 to 2.5 formula: Na2O --( CH3) NO Na1a(AlO)12 (SiO2) 12:27H2O Na2O -- (CH3)4N O The synthetic zeolite known as “Molecular Sieve 5A" is SiO2 1 to 2 a crystalline aluminosilicate salt having an effective pore diameter of about 5 angstronims and in which substan - HO tially all of the 12 ions of sodium in the immediately Na2O --(CH3)4NO 25 to 50 above formula are replaced by calcium, it being under stood that calcium replaces sodium in the ratio of one maintaining the mixture at a temperature of about 100 calcium ion for two sodium ions. A crystalline sodium C. to 120° C. until the crystals are formed, and separat 50 aluminosilicate is also available commercially under the ing the crystals from the mother liquor. The crystal mate name of "Molecular Sieve 13X.' The letter "X" is used rial is thereafter washed until the wash effluent has a to distinguish the inter-atomic structure of this zeolite pH essentially that of wash water and subsequently dried. from that of the 'A' crystal mentioned above. As initially ZK-5 is representative of another crystalline alumino prepared and before activation by dehydration, the 13X silicate which is prepared in the same manner as Zeolite 5 5 ZK-4 except that N,N'-dimethyltriethylenediammonium material contains water and has the unit cell formula hydroxide is used in place of tetramethylammonium hy Nass (AlO4)6(SiO2) 106267H2O droxide. ZK-5 may be prepared from an aqueous sodium The synthetic zeolite known as “Molecular Sieve 10X” is aluminosilicate mixture having the following composition a crystalline aluminosilicate salt in which a substantial expressed in terms of oxide mole ratios as: 60 proportion of the sodium ions of the 13X material have been replaced by calcium. SiO/Al2O3 2.5 to 1. Among the naturally occurring crystalline alumino Na2O silicates which can be employed for purposes of the in vention, the preferred aluminosilicates are those which NaO (Ci)N(CH.) OH 0 to: 5 sorb at least 2 wt. percent normal butane at 1 atm. and HO - 25 C., i.e., those having a pore diameter greater than about 5.4 A. Examples of such aluminosilicates include NaO((CH5N,(CH)OH to 50 faujasite, dachiardite and mordenite. With the latter NaO--(CH2)6N(CH3)2OH 1 to 2 aluminosilicates, it is essential that they be in proper ionic SiO2 70 form, else the pore diameter becomes smaller than 5.4 A. Other aluminosilicates which can be used are those The N,N'-dimethyltriethylenediammonium hydroxide resulting from caustic treatment of various clays. used in preparing ZK-5 can be prepared by methylating Of the clay materials, montmorillonite and kaoline 1,4-diazabicyclo-(2.2.2)-octane with methyl iodide or families are representative types which include the sub dimethyl sulfate, followed by conversion to the hydroxide 75 bentonites, such as bentonite, and the kaolins commonly 3,371,110 3 7 It is to be noted that the material first formed on mixing identified as Dixie, McNamee, Georgia and Florida clays the reactants is an amorphous precipitate which is, gen in which the main mineral constituents is halloysite, erally speaking, not catalytically active in the process of kaolinite, dickite, nacrite or anauxite. Such clays may be the invention. It is only after transformation of the used in the raw state as originally mined or initially sub amorphous precipitate to crystalline form that the highly jected to calcination, acid treatment or chemical modi 5 active catalyst described herein is obtained. fication. In order to render the clays suitable for use, Molecular sieves of the other series may be prepared however, the clay material is treated with sodium hy in a similar manner, the composition of the reaction mix droxide or potassium hydroxide, preferably in admixture ture being varied to obtain the desired ratios of ingre with a source of silica, such as sand, silica gel or Sodium dients for the particular sieve in question. silicate, and calcined at temperatures ranging from 230 i () The molecular sieve catalysts useable in the process F. to 1600 F. Following calcination, the fused material of the present invention may be in the Sodium form as is crushed, dispersed in water and digested in the result aforesaid or may contain other cations including other ing alkaline solution. During the digestion, materials with metallic cations and/or hydrogen. In preparing the non varying degrees of crystallinity are crystallized out of sodium forms of the catalyst composition, the alumino solution: The solid material is separated from the alkaline 5 silicate can be contacted with a non-aqueous or aqueous material and thereafter washed and dried. The treatment fluid medium comprising a gas, polar solvent or Water can be effected by reacting mixtures falling within the solution containing the desired positive ion. Where the following weight ratios: aluminosilicate is to contain metal cations, the metal Na2O/clay (dry basis) 1.0-6.6 to 1 20 cations may be introduced by means of a salt soluble SiO2/clay (dry basis) 0.01-3.7 to 1. in the fuid medium. When the aluminosilicate is to con H2O/Na2O (mole ratio) 35-180 to 1 tain hydrogen ions, such hydrogen ions may be intro Molecular sieves are ordinarily prepared initially in duced by means of a hydrogen ion-containing fluid me the sodium form of the crystal. The sodium ions in such dium or a fluid medium containing ammonium ions ca form may, as desired, be exchanged for other cations, 25 pable of conversion to hydrogen ions. as will be described in greater detail below. In general, In those cases in which the aluminosilicate is to con the process of preparation involves heating, in aqueous tain both metal cations and hydrogen ions, the alumino Solution, an appropriate mixture of oxides, or of ma silicate may be treated with a fluid medium containing terials whose chemical composition can be completely both the metal salt and hydrogen ions or ammonium represented as a mixture of oxides Na2O, Al2O3, SiO2 30 ions capable of conversion to hydrogen ions. Alterna and H2O at a temperature of approximately 100° C. for tively, the aluminosilicate can be first contacted with a periods of 15 minutes to 90 hours or more. The product fluid finedium containing a hydrogen ion or ammonium which crystallizes within this hot mixture is separated ion capable of conversion to a hydrogen ion and then therefrom and water washed until the water in equilibrium with a fluid medium containing at least one metallic salt. with the zeolite has a pH in the range of 9 to 12. After 35 Similarly, the aluminosilicate can be first contacted with activating by heating until dehydration is attained, the a fluid medium containing at least one metallic salt and substance is ready for use. then with a fluid medium containing a hydrogen ion or For example, in the preparation of sodium zeolite “A,” an ion capable of conversion to a hydrogen ion or a suitable reagents for the source of silica include silica sol, mixture of both. silica gel, silicic acid or sodium silicate. Alumina can be 40 Water is the preferred medium for reasons of economy Supplied by utilizing activated alumina, gamma alumina, and ease of preparation in large scale operations involv alpha alumina, aluminum trihydrate or sodium aluminate. ing continuous or batchwise treatment. Similarly, for this Sodium hydroxide is suitably used as the source of the reason, organic solvents are less preferred but can be em sodium ion and in addition contributes to the regulation of ployed providing the solvent permits ionization of the the pH. All reagents are preferably soluble in water. The acid, ammonium compound and metallic salt. Typical sol reaction solution has a composition, expressed as mix vents include cyclic and acyclic ethers such as dioxane, tures of oxides, within the following ranges: SiO/Al2O tetrahydrofuran, ethyl ether, diethyl ether, diisopropyl of 0.5 to 2.5, Na2O/SiO2 of 0.8 to 3.0 and HO/Na2O of ether, and the like; ketones such as acetone and methyl 35 to 200. A convenient and generally employed process ethyl ketone; esters such as ethyl acetate, propyl acetate; of preparation involves preparing an aqueous solution of alcohols Such as ethanol, propanol, butanol, etc.; and mis Sodium aluminate and sodium hydroxide and then add cellaneous solvents such as dimethylformamide, and the ing with stirring an aqueous solution of sodium silicate. like. The reaction mixture is placed in a suitable vessel which The hydrogen ion, metal cation or ammonium ion may is closed to the atmosphere in order to avoid losses of be present in the fluid medium in an amount varying water and the reagents are then heated for an appropriate within wide limits dependent upon the pH value of the length of time. Adequate time must be used to allow for 5 5 fluid medium. Where the aluminosilicate material has a recrystallization of the first amorphous precipitate that molar ratio of silica to alumina greater than about 5.0, forms. While satisfactory crystallization may be obtained the fluid medium may contain a hydrogen ion, metal ca at temperatures from 21 to 150° C., the pressure being tion, ammonium ion, or a mixture thereof, equivalent to atmospheric or less, corresponding to the equilibrium of a pH value ranging from less than 1.0 up to a pH value the vapor pressure with the mixture at the reaction tem 60 of about 10.0. Within these limits, pH values for fluid perature, crystallization is ordinarily carried out at about media containing a metallic cation and/or an ammonium 100 C. As soon as the zeolite crystals are completely ion range from 4.0 to 10.0, and are preferably between a formed they retain their structure and it is not essential pH value of 4.5 to 8.5. For fluid media containing a hy to maintain the temperature of the reaction any longer drogen ion alone or with a metallic cation, the pH values in order to obtain a maximum yield of crystals. range from less than 1.0 up to about 7.0 and are prefer After formation, the crystalline zeolite is separated ably within the range of less than 3.0 up to 6.0. Where from the mother liquor, usually by filtration. The crys the molar ratio of aluminosilicate is greater than about talline mass is then washed, preferably with salt-free 3.0 and less than about 5.0, the pH value for the fluid water, which on the filter, until the wash water, in equi 70 media containing a hydrogen ion or a metal cation ranges librium with the zeolite, reaches a pH of 9 to 12. The from 3.8 to 8.5. Where ammonium ions are employed, crystals are then dried at a temperature between 25 C. either alone or in combination with metallic cations, the and 150° C. Activation is attained upon dehydration, pH value ranges from 4.5 to 9.5 and is preferably within as for example at 350° C. and 1 mm. pressure or at 350 the limit of 4.5 to 8.5. When the aluminosilicate material C. in a stream of dry air. 75 has a molar ratio of silica to alumina less than about 3.0, 3,371,110 9 10 the preferred medium is a fluid medium containing an am formic acid, stearic acid, monium ion instead of a hydrogen ion. Thus, depending acetic acid, oxalic acid, uponin rather the silicawide limits.to alumina ratio, the pH value varies with chloroacetic acid, malonic acid, dichloroacetic acid, succinic acid, In carrying out the treatment with the fluid medium, trichloroacetic acid, glutaric acid, the procedure employed comprises contacting the alu bromoacetic acid, adipic acid, minosilicate with the desired fluid medium or media until propionic acid, pimelic acid, such time as metallic cations originally present in the all 2-bromopropionic acid, suberic acid, minosilicate are removed to the desired extent. Repeated 3-bromopropionic acid, aZelaic acid, use of fresh solutions of the entering ion is of value to 10 lactic acid, sebacic acid, secure more complete exchange. Effective treatment with n-butyric acid, alkylsuccinic acid, the fluid medium to obtain a modified aluminosilicate hav isobutyric acid, alkenylsuccinic acid, ing high catalytic activity will vary, of course, with the crotonic acid, maleic acid, duration of the treatment and temperature at which it is n-valeric acid, fumaric acid, carried out. Elevated temperatures tend to hasten the 5 isovaleric acid, itaconic acid, speed of treatment whereas the duration thereof varies n-caproic acid, citraconic acid, inversely with the concentration of the ions in the fluid oenanthic acid, mesaconic acid, medium. In general, the temperatures employed Tange pelargonic acid, glutonic acid, from below ambient room temperature of 24° C. up to capric acid, muconic acid, temperatures below the decomposition temperature of the 20 undecyclic acid, ethylidene malonic acid, aluminosilicate. Following the fluid treatment, the treated lauric acid, isopropylidene malonic aluminosilicate is washed with water, preferably distilled myristic acid, acid, water, until the effluent wash water has a pH value of palmitic acid, allyl malonic acid. wash water, i.e., between about 5 and 8. The aluminosili cate material is thereafter analyzed for metallic ion con Representative aromatic and cycloaliphatic monocar tent by methods well known in the art. Analysis also in boxylic dicarboxylic and polycarboxylic acids include volves analyzing the effluent wash for anions obtained in 1,2-cyclohexanedicarboxylic acid, the wash as a result of the treatment, as well as determi 14-cyclohexanedicarboxylic acid, nation of and correction for anions that pass into the 2-carboxy-2-methylcyclohexaneacetic acid, effluent wash from soluble substances or decomposition 30 phthalic acid, products of insoluble substances which are otherwise pres isophthalic acid, ent in the aluminosilicate as impurities. The aluminosili terephthalic acid, cate is then dried and dehydrated. 1,8-naphthalenedicarboxylic acid, 1,2-naphthalenedicarboxylic acid, The actual procedure employed for carrying out the tetrahydrophthalic acid, fluid treatment of the aluminosilicate may be accom 3-carboxy-cinnamic acid, plished in a batchwise or continuous method under at hydrocinnamic acid, mospheric, subatmospheric or superatmospheric pressure. pyrogallic acid, A solution of the ions of positive valence in the form of benzoic acid, a molten material, vapor, aqueous or non-aqueous solu 40 Ortho, tion, may be passed slowly through a fixed bed of the alu meta and para-methyl, minosilicate. If desired, hydrothermal treatment or a cor hydroxy, responding non-aqueous treatment with polar solvents may be effected by introducing the aluminosilicate and fluid chloro, medium into a closed vessel maintained under autogene phenylaceticbromo and nitro-substitutedacid, benzoic acids, ous pressure. Similarly, treatments involving fusion or mandelic acid, vapor phase contact may be employed providing the melt benzylic acid, ing point or vaporization temperature of the acid or am hippuric acid, monium compound is below the decomposition tempera benzenesulfonic acid, ture of the aluminosilicate. toluenesulfonic acid, A wide variety of acidic compounds can be employed methanesulfonic acid with facility as a source of hydrogen ions and include and the like. both inorganic and organic acids. Other sources of hydrogen ions include carboxy poly Representative inorganic acids which can be employed esters prepared by the reaction of an excess of polycar 55 boxylic acid or an anhydride thereof and a polyhydric include acids such as hydrochloric acid, hypochlorous alcohol to provide pendant carboxyl groups. acid, chloroplatinic acid, sulfuric acid, sulfurous acid, hy Still other materials capable of providing hydrogen drosulfuric acid, peroxydisulfonic acid (HSOs), peroxy ions are ion exchange Fesins having exchangeable hy monosulfuric acid (H2SO5), dithionic acid (H2SO), sul drogen ions attached to base resins comprising cross famic acid (H2NHSH), amidodisulfonic acid 60 linked resinous polymers of monovinyl aromatic mono (NH(SOH)), mers and polyvinyl compounds. These resins are well known materials which are generally presented by co chlorosulfuric acid, thiocyanic acid, hyposulfurous acid polymerizing in the presence of a polymerization catalyst (H2SO4), pyrosulfuric acid (H2SO), thiosulfuric acid one or more monovinyl aromatic compounds, such as (H2S2O3), nitrosulfonic acid (HSO.NO), hydroxylamine 65 styrene, vinyl toluene, vinyl Xylene, with one or more disulfonic acid (HSO3)2NOHI, nitric acid, nitrous acid, divinyl aromatic compounds such as divinyl benzene, hyponitrous acid, carbonic acid and the like. divinyl toluene, divinyl. xylene, divinyl naphthalene and Typical organic acids which find utility in the practice divinyl acetylene. Following copolymerization, the resins of the invention include the monocarboxylic, dicarboxylic are sulfonated to provide the hydrogen form of the resin. and polycarboxylic acids which can be aliphatic, aromatic 70 Still another class of compounds which can be em or cycloaliphatic in nature. ployed are ammonium compounds which decompose to Representative aliphatic monocarboxylic, dicarboxylic provide hydrogen ions when an aluminosilicate treated and polycarboxylic acids include the saturated and un with a solution of said ammonium compound is subjected to temperatures below the decomposition temperature of saturated, substituted and unsubstituted acids such as 75 the aluminosilicate. 3,371,110 12 Representative ammonium compounds which can be calcium carbonate, cupric salicylate, employed include calcium chloride, cupric acetate, calcium citrate, uranyl acetate, ammonium hydroxide, ammonium chloroplum beryllium bromide, uranyl chloride, ammonium chloride, bate, beryllium carbonate, uranyl nitrate, ammonium bromide, ammonium citrate, beryllium hydroxide, chromic acetate, ammonium iodide, ammonium dithionate, beryllium sulfate, chromic chloride, ammonium carbonate, anmonium fluoride, barium acetate, chromic nitrate, ammonium bicarbonate, ammonium gallate, barium bromide, chromic sulfate, ammonium sulfate, ammonium nitrate, barium carbonate, ferric chloride, ammonium sulfide, ammonium nitrite, O barium citrate, ferric bromide, ammonium thiocyanate, ammonium formate, barium malonate, ferric acetate, ammonium dithiocarbamate, ammonium propionate, barium nitrite, ferrous chloride, ammonium peroxysulfate, ammonium butyrate, barium oxide, ferrous arsenate, ammonium acetate, ammonium Valerate, barium sulfide, ferrous iactate, ammonium tungstate, ammonium lactate, 5 magnesium chloride, ferrous sulfate, ammonium molybdate, ammonium malonate, magnesium bromide, nickel chloride, ammonium benzoate, ammonium oxalate, magnesium sulfate, nickel bromide, ammonium borate, ammonium palmitate, magnesium sulfide, cerous acetate, ammonium tartrate ammonium carbamate, 20 magnesium acedate, cerous bromide, ammonium sesquicarbonate, and the like. magnesium formate, cerous carbonate, Still other ammonium compounds which can be employed magnesium stearate, cerous chloride, include complex ammonium compounds Such as tetra magnesium tartrate, cerous iodide, methylammonium hydroxide, trimethylammonium chlo manganese chloride, cerous sulfate, 25 manganese sulfate, cerous sulfide, ride. Other compounds which can be employed are nitro magnesium acetate, lanthanum chloride, gen bases such as the salts of guanidine, pyridine, quino manganese carbonate, lanthanum bromide, line, etc. manganese carbonate, lanthanum nitrate, A wide variety of metallic compounds can be employed manganese formate, anthanum sulfate, with facility as a source of metallic cations and include lanthanum sulfide, both inorganic and organic salts of the metals of Groups 30 zinc sulfate, yttrium bromate, I through VIII of the Periodic Table. zinc nitrate, Representative of the salts which can be employed in zinc acetate, yttrium bromide, clude chlorides, bromides, iodides, carbonates, bicarbon zinc chloride, yttrium chloride, ates, sulfates, sulfides, thiocyanates, dithiocarbamates, zinc bromide, yttrium nitrate, peroxysulfates, acetates, benzoates, citrates, fluorides, aluminum chloride, yttrium Sulfate, nitrates, nitrites, formates, propionates, butyrates, valer aluminum bromide, Samarium acetate, ates, lactates, malonates, oxalates, palmitates, hydroxides, aluminum acetate, samarium chloride, tartrates and the like. The only limitation on the particu aluminum citrate, Samarium bromide, lar metal salt or salts employed is that it be soluble in aluminum nitrate, samarium sulfate, the fluid medium in which it is used. The preferred salts 40 aluminum oxide, neodymium chloride, are the chlorides, nitrates, acetates and sulfates. aluminum phosphate, neodymium oxide, Rare earth salts may be advantageously employed. Such aluminum Sulfate, neodymium sulfide, salts can either be the salt of a single metal or, preferably, titanium bromide, neodymium sulfate, of mixtures of metals such as a rare earth chloride or titanium chloride, praseodymium chloride, didymium chlorides. As hereinafter referred to, a rare titanium nitrate, praseodymium bromide, earth chloride solution is a mixture of rare earth chlorides titanium sulfate, praseodymium sulfate, consisting essentially of the chlorides of lanthanum, zirconium chloride, praseodymium sulfide, cerium, neodymium and praseodymium with minor Zirconium nitrate, selenium chloride, amounts of samarium, gadolinium and yttrium. The rare zirconium sulfate, earth chloride solution is commercially available and it cupric sulfate, selenium bromide, contains the chlorides of a rare earth mixture having the cupric phosphate, tellurium chloride, relative composition: cerium (as CeO2) 48% by weight; cupric benzoate, tellurium bromide, etc. lanthanum (as La Oa) 24% by weight; praseodymium The aluminosilicate catalysts useable in connection with (as PreO11) 5% by weight; neodymium (as Nd2O3) 7% the process of the present invention may be used in by weight; Samarium (as Sm2O3) 3 % by weight; gado 5 5 powdered, granular or molded state formed into spheres linium (as Gd2O3) 2% by weight; yttrium (as YO) or pellets of finely divided particles having a particle 0.2% by weight; and other rare earth oxides 0.8% by size of 2 to 500 mesh. In cases where the catalyst is weight. Dydmium chloride is also a mixture of rare earth molded, such as by extrusion, the aluminosilicate may be chlorides, but having a low cerium content. It consists extruded before drying, or dried or partially dried and of the following rare earths determined as oxides: lan 60 then extruded. The catalyst product is then preferably thanum, 45-46% by weight; cerium, 1-2% by weight; precalcined in an inert atmosphere near the temperature praseodymium, 9-10% by weight, neodymium, 32-33% contemplated for conversion but may be calcined initially by weight; samarium, 5-6% by weight; gadolinium, 3 during use in the conversion process. Generally, the 4% by weight; yttrium, 0.4% by weight; other rare aluminosilicate is dried between 150 F. and 600 F. and earths, 1-2% by weight. It is to understood that other thereafter calcined in air or an inert atmosphere of nitro mixtures of rare earths are equally applicable in the gen, hydrogen, helium, flue gas or other inert gas at tem instant invention. peratures ranging from about 500 F. to 1500 F. for Representative metal salts which can be employed, periods of time ranging from 1 to 48 hours or more. aside from the mixture mentioned above, include The aluminosilicate catalysts prepared in the fore 70 going manner may be used as catalysts per se or as inter silver nitrate, silver tartrate, mediates in the preparation of further modified contact silver acetate, calcium acetate, masses consisting of inert and/or catalytically active silver arsenate, calcium arsenate, materials which otherwise serve as a base, support, carrier, silver citrate, calcium benzoate, silver oxide, calcium bromide, 75 binder, matrix or promoter for the aluminosilicate. One 3,371,110 13 14 embodiment of the invention is the use of the finely divided out either on a batch basis or in a continuous manner. aluminosilicate catalyst particles in a siliceous gel matrix Batch treatment of the charge stock may be effected in wherein the catalyst is present in such proportions that reactors or autoclaves of suitable design in which the the resulting product contains about 2 to 95% by weight, charge and catalyst are exposed to the desired conditions preferably about 5 to 75% by weight, of the alumino 5 of operation for a time sufficient to effect the desired silicate in the final composite. results. Under such conditions of operation, the crystalline The aluminosilicate-siliceous gel compositions can be aluminosilicate catalyst should be present in a quantity of prepared by several methods wherein the aluminosilicate approximately 5-20% by weight of the mixture of catalyst is combined with silica while the latter is in a hydrous and charge stock. state such as in the form of a hydrosol, hydrogel, wet O The process of the present invention is preferably car gelatinous precipitate or a mixture thereof. Thus, silica ried out on a continuous basis in a reactor containing a gel formed by hydrolyzing a basic solution of alkali metal fixed bed or layer of the crystalline aluminosilicate cata silicate with an acid such as hydrochloric, sulfuric, etc., lyst through which the charge stock is passed under the can be mixed directly with finely divided aluminosilicate desired conditions of temperature and pressure. Under having a particle size less than 40 microns, preferably such conditions of operation, the reaction products are within the range of 2 to 7 microns. The mixing of the discharged continuously from the reactor at substantially two components can be accomplished in any desired the same rate as that under which the charge stock is manner, such as in a ball mill or other types of kneading fed into the reactor. If desired, of course, a continuous mills. Similarly, the aluminosilicate may be dispersed in process utilizing a fluidized bed may be employed in a a hydrosol obtained by reacting an alkali metal silicate 20 conventional manner. When a continuous process is em with an acid or an alkaline coagulant. The hydrosol is then ployed, liquid hourly space velocities of about 0.25-2.0 permitted to set in mass to a hydrogel which is thereafter volumes of reactant fluid/vol. catalyst/hr. and gaseous dried and broken into pieces of desired shape, or dispersed space velocities of about 100-1000 volumes of reactant through a nozzle into a bath of oil or other water-im gas/vol. catalyst/hr. may be advantageously employed. miscible suspending medium to obtain spheroidally shaped The reaction conditions employed in the process of the “bead' particles of catalyst. The aluminosilicate siliceous present invention will necessarily vary depending upon gel thus obtained is washed free of soluble salts and the starting material employed. The temperatures em thereafter dried and/or calcined as desired. ployed in the process of the present invention are approxi The siliceous gel matrix may also consist of a plural mately 400-700° F. with temperatures of 400-600 F. gel comprising a predominant amount of silica with one 30 being preferred. While atmospheric pressure is preferred or more metals or oxides thereof. The preparation of for most desirable results, elevated pressures may also be plural gels is well known and generally involves either used. separate precipitation or coprecipitation techniques in To produce phenolic compounds in accordance with which a suitable salt of the metal oxide is added to an the process of the present invention, it is necessary to alkali metal silicate and an acid or base, as required, is 3 5 supply an oxidizing medium to the reaction Zone in con added to precipitate the corresponding oxides. The silica tact with the starting aromatic carboxylic acid. Such oxi content of the siliceous gel matrix contemplated herein is dizing medium may be provided in the form of any other generally with the range of 55 to 100 weight percent with wise inert gas containing elemental oxygen including, for the metal oxide content ranging from zero to 45 percent. example, ozone, gaseous oxygen or air, the use of air Minor amounts of promoters or other materials which 40 being most convenient and economical. Where a liquid may be present in the composition include cerium, chro phase acid is utilized, the reaction will accordingly take mium, cobalt, tungsten, uranium, platinum, lead, zinc, place between a liquid and a gas phase. calcium,compounds. magnesium, lithium, silver, nickel and their As previously indicated, an intermediate product ob The aluminosilicate catalyst may also be incorporated tained from the process of the present invention is the in an alumina gel matrix conveniently prepared by adding 45 ester of the starting aromatic carboxylic acid. As an ammonium hydroxide, ammonium carbonate, etc. to a example, with benzoic acid as a starting material, phenyl salt of aluminum, such as aluminum chloride, aluminum benzoate is an intermediate reaction product. This inter Sulfate, aluminum nitrate, etc., in an amount to form mediate ester is, in accordance with the process of the aluminum hydroxide, which, upon drying, is converted present invention, converted to the desired phenol through to alumina. The aluminosilicate catalyst can be mixed 50 hydrolysis, which may be effected conveniently by the with the dried alumina or combined while the alumina introduction of water into the reaction system. For most is in the form of a hydrosol, hydrogel or wet gelatinous desirable results, such water may be introduced in the precipitate. form of steam. Since one of the by-products of the hydrolysis reaction will be the starting aromatic carbox In general, the preferred crystalline aluminosilicates for 55 ylic acid, a sufficient stoichiometric excess of water should use in the process of the present invention are those con be utilized in the hydrolysis reaction to convert the inter taining copper. Also particularly advantageous in carrying mediate ester to the desired phenol and aromatic car out the process of the present invention are the crystalline boxylic acid to the maximum extent so that the carboxylic aluminosilicates containing nickel and/or uranyl cations, acid can be reutilized as starting material for maximum If desired, a mixture of such catalysts (i.e., a mixture 60 efficiency. Similarly, it is desirable to use a slight excess employed.of copper 13X and nickel 13X molecular sieves) may be of oxygen in the oxidation reaction over that theoretically needed to convert the acid to its correspinding ester. For maximum effectiveness in carrying out the process In carrying out the process of the present invention on of the present invention, the crystalline aluminosilicate a continuous basis, the phenolic compound produced will used as a catalyst should have pores or channels of a size 65 be removed from the reactor as a vapor along with vola such that the reactants will pass into such pores or tile by-products and unconsumed starting materials. channels and the reaction products will be removable These vapors may be separated from one another and therefrom. Quite obviously, the particular pore size which the phenolic product isolated therefrom by conventional is desirable will vary depending upon the particular start techniques. Merely by way of example, the phenolic com ing materials utilized and the products to be formed as 70 pound may be absorbed by conventional solvent extrac a result of the reaction. In general, it can be stated that tion techniques or may be selectively condensed in a dis the most desirable molecular sieves for use in the instant tillation column if there is a significant difference between process are those having a pore size of approximately the boiling point of the acid and that of the phenol. 7-15 A. When the reactor is operated so that the reaction The process of the present invention may be carried 75 products are in vapor form, a complex high boiling mix 3,371,110 5 6. ture may accumulate in the reaction zone, which accumu 5. A method as defined in claim wherein said aro lation may gradually reduce the reactor efficiency. Such matic monocarboxylic acid is in the liquid phase. eficiency may be maintained at a high level through the 6. A method as defined in claim ; wherein said cata periodic withdrawal of such complex high boiling mix lyst contains at least two metal cations, one of said cations ture, separating the undesirable portion of it and return 5 catalyzing the oxidation reaction and the other of Said ing the usable portion to the reaction for further reaction. cations serving as a promoter to prevent side reactions. The following example will illustrate the practice of 7. A method as defined in clain 6 wherein said pro the present invention: noter and catalyzing cations are both carried by the same One hundred twenty grams of benzoic acid and fifteen crystalline aluminosilicate. grams of a copper exchanged 13X molecule sieve are O 8. A method as defined in claim 6 wherein each of said charged into a stirred cylindrical reaction vessel. Agita cations is exchanged on a separate crystalline alumino tion is provided by a mechanical stirrer. Air and steam, silicate and the exchanged crystalline aluminosilicates each at 500 ml./minute, are passed through the heated mixed together. reactants heated at 250 C. The gases and volatile re 9. A method as defined in claim wherein said aro action products are passed through a reflux condenser 5 matic monocarboxylic acid is benzoic acid and said ester for returning liquid products and reactants to the reactor. is phenyl benzoate. After three hours the products are analyzed and, in addi 10. A process for oxidizing a compound of the tion to unreacted benzoic acid, contained about 30 grams formula ArCOOH to form an ester of the formula of phenol. Minor amounts of benzene and tarry by ArCOOAr, wherein said Ar is an aromatic hydrocarbon products are also observed. 20 radical and wherein said COOH group is attached di In addition to the foregoing, various materials serve rectly to said aromatic hydrocarbon radical, connprising to promote the carrying out of the process of the present bringing said acid into contact with an otherwise inert application. For example, materials such as the salts of gas containing elemental oxygen in the presence of a magnesium, sodium, potassium, cobalt, lithium and solid, porous, positive ion-containing crystalline alumino barium help to prevent by-product tar formation when silicate molecular sieve catalyst, the pores of said Crystal they are present during the carrying out of the oxidation line aluminosilicate being of a size such as to permit of the carboxylic acids to their corresponding phenols. ingress therein of said ArCOOH and egress therefrom Such promoter materials may be introduced into the re of said ArCOOAr. action environment either through a mixture of crystalline 11. A process as defined in claim i8 wherein said aluminosilicates (i.e., a copper exchanged 13X molecular ArCOOH is in the liquid phase and wherein said cata sieve mixed with a potassium exchanged 13X molecule iyst contains at least one metal cation. sieve) or, preferably, by utilizing a single type of crystal 12. A process as defined in claim A1 wherein Said line aluminosilicate containing both catalytic and pro metal cation is selected from at least one of the group moter cations (i.e., a potassium molecular sieve in which consisting of copper, nickel and liranium. part of the potassium has been replaced by copper ions). 3. 5 13. A method of synthesizing phenolic compounds in the foregoing portions of the specification, a novel comprising placing an aromatic monocarboxylic acid in process for the catalytic conversion of aromatic carbox the presence of a solid, porous, positive ion-containing ylic acids to phenolic compounds using solid, porous crystalline aluminosilicate molecular sieve catalyst; Sub crystalline aluminosilicate catalysts has been set forth. jecting said acid while in the presence of said catalyst It is to be understood, however, that the practice of the 40 to an oxidation reaction by bringing said acid into con present invention is also applicable to isomorphs of said tact with an otherwise inert gas containing elemental crystalline aluminosilicates. For example, the aluminum oxygen to convert said acid to an ester thereof; and may be replaced by elements such as gallium and silicon subjecting said ester while in the presence of Said cata by elements such as germanium. lyst to a hydrolysis reaction to convert said ester to form The invention may be embodied in other specific forms 45 the desired phenolic compound, the pores of Said Crystal without departing from the spirit or essential character line aluminosilicate being of a size such as to permit in istics thereof. The present embodiment is therefore to be gress therein of the reactants in said oxidation and hy considered in all respects as illustrative and not restric drolysis reactions and egress therefrom of the reaction tive, the scope of the invention being indicated by the products resulting from said reactions. appended ciaims rather than by the foregoing description, 50 14. A method as defined in claim 3 wherein said and all changes which come within the meaning and range acid is in the liquid phase. of equivalency of the claims are therefore intended to be 15. A method as defined in claim 14 wherein said embraced therein. catalyst contains a metal selected from at least one of What is claimed is: the group consisting of copper, nickel and uranium. 1. A method of oxidizing an aromatic monocarboxylic 5 5 6. A method as defined in claim i3 wherein said cata acid to an ester thereof, said acid having its carboxyl lyst contains pores of approximately 7-15 A. in di group attached directly to the aromatic ring, comprising ameter. bringing said acid into contact with an otherwise inert gas 17. A method as defined in claim 13 wherein said oxi containing elemental oxygen in the presence of a solid, po dation and hydrolysis reactions are carried out at a tem rous, positive ion-containing, crystalline aluminosilicate 60 perature of about 400-700 F. molecular sieve catalyst, the pores of said crystalline alu minosilicate being of a size such as to permit ingress References Cited therein of said monocarboxylic acid and egress there UNITE STATES PATENTS from of said ester. 2. A method as defined in claim wherein said cata 65 2,727,926 12/1955 Kaeding et al. ------260-621. lyst contains at least one metal cation. 2,762,838 9/1956 Toland ------260-621. 3. A method as defined in claim 2 wherein said metal cation is selected from at least one of the group consist BERNARD HELFIN, Acting Primary Examiner. ing of copper, nickel and uranium. LEON ZITVER, Examiner. 4. A method as defined in claim 2 wherein said metal 70 cation is copper, D. M. HELFER, H. ROBERTS, Assistant Examiners.