Patented Mar. 11, 1952 2,588,512 UNITED STATES PATENT OFFICE 2,588,512 WNYL CHORIDE PLASTCZE) WTH ALKYL BENZY TETRACHLORO Harry R. Gamrath, St. Louis, and William E. Weesner, Webster Groves, Mo., assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application May 13, 1950, Seria No. 161,902 9 Claims. (C1. 260-31.8) This invention relates to alkylbenzyl tetrachlo benzyl tetrachlorophthalates wherein the alkyl rophthalates; more specifically, this invention substituent contains from 1 to 9 carbon atoms relates to alkyl benzyl tetrachlorophthalates constitute an unusual class of tetrachlorophthalic wherein the alkyl radical contains from 1 to 9 acid esters. It has been found that these esters carbon atoms, and their method of preparation. are extremely compatible with vinyl chloride This invention also relates to vinyl chloride poly containing polymers permitting the preparation ners plasticized with alkyl benzyl tetrachloro of plasticized vinyl chloride-containing resinous phthalates wherein the alkyl substituent contains compositions having outstanding properties and from 1 to 9 carbon atoms. performance characteristics. It has further been Some esters of tetrachlorophthalic acid have 10 found that these alkyl benzyl tetrachloro been disclosed in the art and various utilities phthalates are most unusual in that they are all aScribed to them. Of particular interest is the liquids at room temperature. This character Suggested use of these esters as for istic is particularly surprising in view of the fact various Synthetic resins. As a group however, that the dimethyl, diethyl, dicetyl and dibenzyl the esters of tetrachlorophthalic acids hereto 15 esters of tetrachlorophthalic acid are hav fore known are not universally applicable or use ing relatively high melting points. ful as plasticizers for synthetic resins, partic The alkyl benzyl tetrachlorophthalates of this ularly those polymers or copolymers containing invention may be conveniently prepared by re combined vinyl chloride. In the plasticization acting an alkali metal of a monoalkyl tetra of Synthetic resins, liquid plasticizers are pre 20 chlorophthalic acid, wherein the alkyl substituent ferred to plasticizers as liquid plasticizers contains from 1 to 9 carbon atoms, with benzyl are, as a general rule, more efficient than solid chloride as illustrated in the following examples: plasticizers and obviously easier to handle and EXAMPLE I process. Therefore, such esters as the dimethyl, diethyl, dicetyl and dibenzyl esters of tetrachlo 25 Methyl benzyl tetrachlorophthalate rophthalic acid, which are solids melting at 92° C., To a One-liter, round-bottom, three-necked 60.5° C., 49-50° C. and 92-93° C. respectively, flask provided with an agitator, a thermometer Beilstein, 9, 820, are not particularly desirable as and a reflux condenser "were charged, 318 g. of plasticizers for synthetic resins. Furthermore, dry and 143.0 g. of tetrachlorophthalic many of the esters of tetrachlorophthalic anhy 30 anhydride. The mass was heated by means of a dride heretofore known are actually incompatible glycerin bath to the reflux temperature until with resins which contain combined vinyl chlo the formation of the half-ester, monomethyl ride. For example di(n-decyl) tetrachloro tetrachlorophthalate was essentially complete. is incompatible with , Next the mass was cooled to slightly below the as shown in U. S. Patent 2,462,601. Similarly, it : reflux temperature (60-65 C.) and 36.1 g. of has been found that benzyl n-decyl tetrachloro solid, anhydrous was then phthalate is also incompatible with polyvinyl chlo added during the course of about one hour. To ride at a 40% concentration. the potassium methyl tetrachlorophthalate were It is an object of this invention, therefore, to added 63.3 g. of benzyl chloride and 2 cc. of provide a new class of esters of tetrachloro 40 dimethylcyclohexylamine. The mass was next phthalic acid. heated and the excess methanol was distilled . It is a further object of this invention to pro from the reaction mass until about 217 g. of Vide a new class of esters of tetrachlorophthalic methanol was removed. Thereafter, the maSS acid which esters are liquids at room temperature was refluxed (70-72° C.) for about 16 hours. and are compatible with synthetic resins con 45 The crude methyl benzyl tetrachlorophthalate taining predominantly combined vinyl chloride. was purified by distilling off the excess Solvents A further object of this invention is to provide to a mass temperature of 135° C. Then the a proceSS for the preparation of a new class of residue in the still was cooled and treated with esters of tetrachlorophthalic acid. 250 cc. of to dissolve the potassium chlo A still further object of this invention is to pro 50 ride. This salt Solution-ester mixture was made vide synthetic resinous compositions comprising alkaline to phenolphthalein paper with SOdium a vinyl chloride-containing and a plas carbonate. After separating the aqueous phase, ticizer therefor. the ester was steamed at 103-105 C. until about Further objects will become apparent from the 500 cc. of distillate was collected. Thereafter, description of the invention contained herein. the ester was cooled, washed once with dilute It has now been discovered that the alkyl aqueous alkali, twice with water and finally dried 2,588,512 3. 4. by heating under reduced pressure. From the EXAMPLE W reactants listed, 120.4 g. of methyl benzyl tetra 6-Methylheptyl benayl tetrachlorophthalate chlorophthalate was obtained. In accordance with the proceduce described in PROPERTIES s Example II, 185.9 g. of 6-methylheptyl benzyl Sp. gr. at 25/25 C------14678 tetrachlorophthalate was obtained utilizing the No' ------15880 following reactants: Pour point------F. --40 143.0 g. tetrachlorophthalic anhydride EXAMPLE I 71.6 g. 6-methylheptanol O 63.3 g. benzyl chloride 3,5,5-Trimethylheacyl benayl tetrachloro 34.8 g. anhydrous potassium Carbonate phthalate 2 cc. dimethyl cyclohexylamine To a reactor system as described in Example I were charged 79.5 g. of 3,5,5-trimethylhexyl alco 6-methylheptyl benzyl tetrachlorophthalate hol and 143.0 g. of tetrachlorophthalic anhydride. s thus obtained had the following properties: The mixture was Stirred and heated until the Sp. gr. at 25/25 C------12808 formation of the half-ester, mono-nonyl tetra ND” ------1550 chlorophthalate Was eSSentially complete. For Pour point ------F. --15 the formation. Of the half-ester, the mass was held at about 135-140° C. for approximately two 20 In addition to the alkyl benzyl tetrachloro hours. Then the half-ester was cooled to phthalates prepared in the preceding five ex 110-115° C. and 63.3 g. of benzyl chloride was amples, the following alkyl benzyl tetrachloro added in about five minutes. With the mass phthalates are further illustrations of esters in temperature in the range of 95-100° C., and during cluded within the scope of this invention: the course of about 30 minutes, 35.1 g. of Solid, 25 Ethyl benzyl tetrachlorophthalate anhydrous potassium carbonate (assay 98.6%) Propylbenzyl tetrachlorophthalate was charged. Then the mixture Was heated at Isopropylbenzyl tetrachlorophthalate about 125-130° C. for approximately 18 hours. Sec. butylbenzyl tetrachlorophthalate Agitation of the mass Was continuous throughout Isobutylbenzyltetrachlorophthalate all operations. 30 Tert, butyl benzyl tetrachlorophthalate Crude 3,5,5-trimethylhexyl benzyl tetrachloro Amyl benzyl tetrachlorophthalate phthalate was purified by a technique similar to Isoamylbenzyl tetrachlorophthalate that described in Example I. The purified, dried Hexyl benzyl tetrachlorophthalate nonyl benzyl tetrachlorophthalate weighed 2-Ethylbutyl benzyl tetrachlorophthalate 14.3 g. 3 5 2-Methylpentylbenzyl tetrachlorophthalate Heptylbenzyl tetrachlorophthalate PROPERTIES Octyl benzyl tetrachlorophthalate Sp. gr. at 25/25 C------12308 Capryl benzyl tetrachlorophthalate No' ------15408 Four point------°F --15 Nonyl benzyl tetrachlorophthalate While specific reactants, quantities of reactants EXAMPLE III and reaction conditions have been set forth in n-Butylbenzyl tetrachlorophthalate the preceding examples, the process for the prep In accordance with the procedure described in aration of the novel compounds of this invention Example II, 182.7 g. of n-butyl benzyl tetra- 4: is subject to substantial variation. The mono chlorophthalate was obtained utilizing the fol alkylester of tetrachlorophthalic acid may be pre lowing reactants: pared in any manner well known to those skilled in the art. Preferably, it is obtained by reacting 143.0 g. tetrachlorophthalic anhydride at least a one molecular proportion of an alkyl 40.7 g. anhydrous n-butanol alcohol containing from 1 to 9 carbon atoms with 63.3 g. benzyl chloride a one molecular proportion of tetrachlorophthalic 34.8 g. anhydrous potassium carbonate anhydride. This reaction is best carried out at n-Butyl benzyl tetrachlorophthalate thus ob an elevated temperature, as for example, in the tained had the following properties: range of from about 50-175° C. Preferably, it Sp. gr. at 25/25 C------1.3849 is carried out by boiling the reaction mixture un No” ------5728 der reflux conditions for the lower alkyl alcohols Four point------F-- -20 and in the temperature range of 125-150° C. for the higher alkyl alcohols. EXAMPLE IV The alkali metal sat of the monoalkyl ester of 2-Ethylheacyl benayl tetrachlorophthalate tetrachlorophthalic acid may also be prepared by any of the methods well known to those skilled In accordance with the procedure described in in the art. Preferably, it is prepared by reacting Example II, 2-ethylhexyl benzyl tetrachloro approximately a 0.5 molecular proportion of an phthalate was obtained utilizing the following alkali metal carbonate, such as sodium or potas reactants: sium carbonate, with a one molecular proportion 143.0 g. tetrachlorophthalic anhydride of the monoalkyl ester of tetrachlorophthalic 71.5 g. 2-ethylhexanol acid. Inasmuch as practically all of the alkali 63.3 g. benzyl chloride metal salts of monoalkyl tetrachlorophthalates 34.7 g. anhydrous potassium carbonate are solids, the reaction is best carried out in the presence of an inert Solvent. If a considerable 2-Ethylhexyl benzyl tetrachlorophthalate thus eXcess of alcohol has been used in the prepara obtained had the following properties: tion of the alkyl tetrachlorophthalic acid, the ex Sp. gr. at 25/25 C------, 1.2771 CeSS alcohol may be utilized as the Solvent. In No" ------1.5500 Such an instance, the alkali metal carbonate is Four point------F. +10 is reacted with the monoalkyl ester of tetrachloro 2,588,512 5 phthalic acid in the excess alcohol and benzyl EXAMPLE WI chloride subsequently added to the reaction mix A mixture containing 60 parts of polyvinyl ture in order to carry out the last step of the re chloride and 40 parts of methyl benzyl tetra action. If approximately equimolecular pro chlorophthalate was milled on a roll mill main portions of the alcohol and tetrachlorophthalic tained at a temperature of 325 F. for a period anhydride are used in the preparation of the of five minutes to form a homogeneous con monoalkyl ester of tetrachlorophthalic acid, the position. The resulting composition was pressed alkali metal carbonate and the benzyl chloride into the form of a sheet in a Suitable mould may be added Simultaneously to the monoalkyl under a pressure of 4,000 lbs. per Square inch ester of tetrachlorophthalic acid in which case O and at a temperature of 325 F. for two minutes. the benzyl chloride and the resultant liquid alkyl The plasticized polyvinyl chloride sheet thus benzyl ester of tetrachlorophthalic acid serve as obtained was found to be transparent and quite a liquid reaction medium. flexible at room temperature. A portion of the The reaction between the alkali metal Salt of sheet was heated for 24 hours in a Freas Cir the monoalkyl ester of tetrachlorophthalic anhy 5 culating air Owen at 105 C. After Such a heating dride and benzyl chloride is best carried out ulti period, it was found that only approximately lizing approximately equimolecular proportions of 2.6% of the methyl benzyl tetrachlorophthalate the reactants. The temperature of the reaction in the plasticized sheet had been lost through may be maintained over a wide range, preferably volatilization. It was further found that this in the range of from about 70° C. to about 175° C. plasticized polyvinyl chloride sheet would not If desired, in Order to Speed the reaction, a cata support combustion when held in the Open flame lyst may be employed. Typical of such catalysts of a Bunsen burner. A plasticized polyvinyl are dimethylcyclohexylamine, triethylamine, or chloride sheet prepared in the manner Similar tertiary amines in general. In place of benzyl to that described above but containing di(2- chloride in this step of the process for preparing ethylhexyl) phthalate, a widely used polyvinyl the novel alkyl benzyl tetrachlorophthalates of chloride plasticizer, burned quite readily when this invention, any of the benzyl halides, such as held in the flame of a Bunsen burner. benzyl bromide, benzyl iodide or benzyl fluoride Inay be utilized. EXAMPLE W. After the reaction is complete, the alkyl Example VI was repeated except that the poly benzyl tetrachlorophthalate may be recovered vinyl chloride was replaced by a copolymer of 90 from the reaction mixture by any of the methods parts vinyl chloride and 10 parts vinyl acetate. Well known to those skilled in the art of the The resulting composition was found to have recovery and purification of esters of tetra properties quite similar to those obtained on chlorophthalic acid. the composition prepared in Example WI. Although the process for the preparation of the alkyl benzyl tetrachlorophthalates just de EXAMPLE WII scribed is the preferred procedure because of Example VI was repeated except that the poly the good yields and high quality of the esters vinyl chloride was replaced by a copolymer of 90 obtained, these compounds can be produced by parts vinyl chloride and 10 parts vinylidene other methods. As examples, tetrachlorophthalic chloride. A tough transparent sheet was ob acid or tetrachlorophthalic anhydride may be tained characterized by good flexibility, excellent reacted with a mixture of benzyl alcohol and an fire retardancy and permanence of plasticizer alkyl alcohol in the presence of an acid catalyst to even under the influence of heat. form the neutral esters. Or, tetrachlorophthalic anhydride may be reacted with benzyl alcohol EXAMPLE X to form monobenzyl tetrachlorophthalate and Example VI was repeated except that the this half-ester may then be reacted with an polyvinyl chloride was replaced by a copolymer alkyl alcohol in the presence of an acid catalyst of 90 parts vinyl chloride and 10 parts diethyl to form the neutral esters. However, in each 50 maleate. The composition thus obtained WaS of these methods the reaction will produce mix found to be extremely flexible, tough, transparent tures of esters, the three principal components and relatively non-flammable. Its excellent being dialkyl tetrachlorophthalate, dibenzyl physical properties were retained even after a tetrachlorophthalate and alkyl benzyl tetra prolonged heating period. chlorophthalate. The alkyl benzyl tetrachloro 55 phthalate can be recovered in pure form from EXAMPLE X the mixture by fractionation, but obviously, only Example VI was repeated except that the in a relatively low yield. methyl benzyl tetrachlorophthalate was replaced The unusual and outstanding properties and by 6-methylhepty benzyl tetrachlorophthalate. characteristics of these alkyl benzyl tetrachloro 60 The composition thus obtained was found to phthalates permit the preparation of novel Syn possess a low temperature flexibility of 0° C. thetic resinous compositions comprising a vinyl when determined in accordance with the method chloride-containing polymer and an alkyl benzyl of Clash and Berg, as described in Ind. Eng. tetrachlorophthalate, wherein the alkyl group Chem, 34, 1218 (1942), a method well known contains from 1 to 9 carbon atons, having out 65 to those skilled in the art of the evaluation of Standing properties and performance chara,c- polyvinyl chloride resins. After 24 hours in a teristics. Such plasticized synthetic resinous Freas circulating air oven at 105° C., Only 2.6% compositions have been found to possess good of the plasticizer in the composition was lost, flexibility, extreme permanance, that is, reten- . indicating excellent permanence of plasticizer. tion of desirable physical properties even in the 70 The composition was also found to be relatively presence of adverse conditions Such as heat, and non-flammable. improved fire retardancy. These outstanding characteristics are illustrated by the following EXAMPLE XI examples, wherein the expression “parts' of Example VI was repeated except that the ingredients is meant to be parts by weight: 5 methyl benzyltetrachlorophthalate was replaced 2,588,512 7 8 by butylbenzyl tetrachlorophthalate. The com alkyl benzyl tetrachlorophthalate may be utilized position thus obtained was found to have a low as the sole plasticizer for the vinyl chloride tennperature flexibility of 3.5° C. After 24 hours containing polymer or it may be used in combina in a Freas circulating air oven at 105 C., only tion with one or more of the commonly used 2.4% of the plasticizer in the composition WaS plasticizers for vinyl chloride-containing poly mers, thereby obtaining a composition having lost. The composition was also found to be rela physical properties attributable to, or resulting tively non-fiammable. from, each of the plasticizer components. Typi EXAMPLE XI cal of such plasticizers which may be utilized in Example VI was repeated utilizing in place of 10 combination with these alkyl benzyl tetrachloro the 40 parts of methyl benzyl tetrachloro phthalates are di(2-ethylhexyl) phthalate, di phthalate, a mixture containing 10 parts of butyl phthalate, tricresyl phosphate, alkyl diary methyl benzyl tetrachlorophthalate and 30 parts phosphates, tri(2-ethylhexyl) phosphate, dibutyl of di(2-ethylhexyl) phthalate. The flammability sebacate, alkylbenzyl phthalates, etc. of this composition was found to be significantly 5 The novel synthetic resinous compositions of less than a composition containing 40 parts of this invention may also have incorporated there di(2-ethylhexyl) phthalate in place of the above in various pigments, fillers, stabilizers, both heat described mixture of di(2-ethylhexyl) phthalate and light, etc. and methyl benzyl tetrachlorophthalate. As indicated by the examples, copolymers of 20 vinyl chloride and other unsaturated materials EXAMPLE XIII copolymerizable therewith may be plasticized Example VI was repeated except that the 40 with the alkyl benzyl tetrachlorophthalates in parts of methyl benzyl tetrachlorophthalate were accordance with this invention. For example, replaced by 30 parts of 2-ethylhexyl benzyl tetra copolymers of vinyl chloride with such materials chlorophthalate. The composition thus ob 25 as vinylidene chloride, vinyl esters of carboxylic tained was found to be extremely flexible, tough, acids, for example, vinyl acetate, vinyl propio transparent and relatively non-flammable. Its nate, vinyl butyrate, vinyl benzoate; esters of un excellent physical properties were retained even saturated acids, for example, alkyl acrylates, after a prolonged heating period. such as methyl acrylate, , propyl 30 acrylate, butyl acrylate, allyl acrylate and the EXAMPLE XIV corresponding esters of methacrylic acid; vinyl Example VI was repeated except that the 40 aromatic compounds, for example, Styrene, parts of methyl benzyltetrachlorophthalate were ortho-chloro-styrene, para-chlorostyrene, 2,5- replaced by 20 parts of 3,5,5-trimethylhexyl dichlorostyrene, 2,4-dichlorostyrene, para-ethyl benzyl tetrachlorophthalate. A tough, trans styrene, divinyl benzene, vinyl naphthalate, parent sheet was obtained characterized by good alpha-methyl styrene; dienes, such as butadiene, flexibility, excellent fire retardancy and per ; amides, such as acrylic acid amide, manence of the plasticizer even under the in acrylic acid anilide; nitriles, such as acrylic acid fluence of heating. nitrile; esters of alpha, beta-unsatulated car The results set forth in Examples VI to XV 40 boxylic acids, for example, the methyl, ethyl, illustrate the outstanding properties of the Syn propyl, butyl, amyl, hexyl, heptyl, octyl, allyl, thetic resinous compositions prepared in accord methallyl, and phenyl esters of maleic, crotonic, ance With this invention. The results clearly itaconic, fumaric acids and the like. The class indicate that Such compositions are character of copolymers in which a predominant portion, ized by extreme toughness, good flexibility, out i. e., more than 50% by weight, of the copolymer standing retention of physical properties even is made from vinyl chloride, represents a pre under adverse conditions and excellent fire re ferred class of polymers to be treated according tardancy. Because of this unusual combination to the invention. of excellent properties, these resinous composi A particularly preferred embodiment of the in tions may be used in the preparation of tough, 50 vention comprises compositions comprised of an flexible, films which films will possess an alkyl benzyl tetrachlorophthalate of this inven exceptionally long life because of the retention tion and a polymer prepared by copolymerizing of their desirable physical properties, and which vinyl chloride and an ester of an alpha, beta films may be used with a greater degree of Safety unsaturated dicarboxylic acid, such as diethyl ill view of the relative non-flammability of these 55 maleate, in which 5 to 20 parts by weight of di films which Substantially eliminates the fire ha2 ethyl maleate are utilized for every 95 to 80 parts ard frequently accompanying the use of plastic by Weight of vinyl chloride. Among the preferred films. esters of alpha, beta-unsaturated dicarboxylic While Examples VI to XIV illustrate particular acids are the alkyl esters in which the alkyl group compositions comprised of a vinyl chloride-con 60 contains from 1 to 8 carbon atoms. taining resin and an alkyl benzyl tetrachloro The alkyl benzyl tetrachlorophthalates where phthalate, it is obvious that substantial variation in the alkyl group contains from 1 to 9 carbon is possible in the preparation and composition of atoms, as disclosed herein, are claimed in our Such resinous compositions. Thus, the quantity Copending application Serial No. 161,901, filed of the alkyl benzyl tetrachlorophthalate utilized 65 May 13, 1950. in such a composition may vary over a wide What is claimed is: range depending upon the properties desired. An 1. A composition comprising a vinyl chloride alkyl benzyl tetrachlorophthalate content of as containing polymer and an alkyl benzyl tetra low as about 5 parts by Weight per 100 parts of chlorophthalate wherein the alkyl group contains the vinyl chloride-containing polymer and as 70 from 1 to 9 carbon atoms. high as 100 parts by weight of the alkyl benzyl 2. A composition comprising polyvinyl chloride tetrachlorophthalate per 100 parts of the vinyl and an alkylbenzyl tetrachlorophthalate wherein chloride-containing polymer has been found to the alkyl group contains from 1 to 9 carbon be useful in preparing improved plasticized Syn atoms. thetic resinous compositions. Furthermore, the 75 3. A composition comprising a copolymer of 2,588,513 10 vinyl chloride and vinyl acetate and an alkyl 8. A composition comprising polyvinyl chloride benzyl tetrachlorophthalate wherein the alkyl and octyl benzyl tetrachlorophthalate. group contains from 1 to 9 carbon atoms. , 9. A composition comprising a coplymer of 4. A composition comprising a vinyl chloride Vinyl chloride and vinyl acetate and Octyl benzyl containing polymer and octyl benzyl tetrachloro 5 tetrachlorophthalate. phthalate. HARRY R. GAMRATH. 5. A composition comprising a vinyl chloride containing polymer and 6-methylhepty benzyl WILLIAM E. WEESNER. tetrachlorophthalate. REFERENCEs CITED 6. A composition comprising a vinyl chloride containing polymer and 2-ethylhexylbenzyltetra The following references are of record in the chlorophthalate. file of this patent: 7. A composition comprising a vinyl chloride UNITED STATES PATENTS containing polymer and butylbenzyl tetrachloro Number Name Date phthalate. 2,460,574. Gresham ------Feb. 1, 1949