[1]Patented June 2, 1953 2 9 6 4 0 @ 8 4 8 UNITED STATES PATENT OFFICE 21640,849 ESTERS OF SULFUR-CONTAINING P4)LYcARBoxyLlc Ac!Ds Denham Harman, Berkeley, and De Loss E. Wiiikleir, Orinda@ Calif., assignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Dirawihg. Application Oett)ber 15, 1949, Setial No. 121,631 11 Claims. This invention relates to it new class of organic s ulfur-colitaining compounds. More t)articulbrly, the invention relates to esters of s iilfur-contaihing polycarboxylic acids, and to their titili2ation, particularly as pla8ticizers for brganic resinous compositions. Specifically, the invention provides new and valuable esters of polyeatbbxylic acids containing at least one sulfonyl radicol joined to celrbon atoms in an open-chain portion of their molecule and mon6hydric alcohols contaiiiing qt least sik carbon atoms, said esters being free Of any aliphatic unsaturation. 'Fhe invention also provides organic rosinous corripositions, particularly the vinyl-type polymers, plasticized With the abovedescribed novel e8ters; Vinyl-type polymers, particularly the vinyl halide polymei-s, may be utilized for many applicati6ns in industry due to their wide range of propp-rties. The polymers find applicatioii in the production of coating conipositions, fibers, films, shaped articles, and the like. These polymers are usually difficult to process and ate quite brittle. however, and before they can be utilized in many of their api3lioations it is neces'sary to 2.-, add thereto some type of plasticizihq agent. The inherent i@isolubility of many of these polyrners makes it difficult to fiiid satisfactory plastici7ets, Substances which act as plasticizeirs for other r(@sinbus material, such as the cellulose di@- @@ 0 rivatiires, are in many Cases iilcolhpatible with this type of polymer. In additi6n, maiiy of the compounds which are comt)atible are tequiri@d in such large amour-its as to impair the dosired physical properties of the said polymer. other com- 3,-, pounds which are otherwi8e satisfactory as plasticizers have a tendency to evapbrate from the plasticized coinposition after short pi@riods of exposure to heat and the compO8ition theil becomes brittle and disintegrates. Still other coM- 40 pounds act as satisfactory plasticizers at or above room temperature but when the temperature is lowered to 01 C. and below the plasticized composition loses its flexibility and is easily cracked. It is an object of the invention, therefore, tO 4 i-) provide a new class of plasticizers for the Vinyltype polymers. It is a further object to provide plo,sticizers for the vinyl-type polymers which have relatively low volatility and are not readily lost from the compounded resin when it is ex- 50 posed to high teinperatures. It is a further object to provide plasticizers for the above-described polymers which impart good loW tempera,ture flexibility to the said resiti. It is a further object to provid6 plasticized Vinyl@type (Cl. 260-481) 2 polymers xvhich possess many improved physical properties. It is a further object to provide a new class of organic sulfur-containing compounds and a method for their preparation. It is a further object to provide novel sulfur-containing esters which possess many unexpected and beneficial properties. Other objects and advantages of the invention will be apparent from the following detailed description thereof. It has now been discovered that these and other objects may be accomplished by the esters of polyearboxylic acids containing at least one sulfonyl radical joined to carbon atoms in an open-chain portion of their molecule and monohydric alcohols contaiiiing at least six carbon 9,toms, said esters being free of any aliphatic unsqturatioii. These esters have proved to be superior plasticizers for the vinyl-type polymers as they are highly conipatible therewith and yield plasticized c6mpositior,s having excellent tonsile strength and flexibility over a wide range of temperatures. In addition, they have been found to have a very low rate of volatilization fro@n the vinyl-type polymers, and compositions cohtaihing these esters are able to withstand long periods of exposure to air and/or relatively high temperatures without shriliking or undergoing any deterioration. The sulfur-containing acids used in producing the novel esters of the inventi-on comprise the polycarbo..-,cyl ic acids containing at least one sulfonyl radical (--SO2-) joined to carbon atoms polymerizable in an open-chain portion of their molecule and being free of any aliphatic unsaturation, i. e., free of any ethylenic or acetylenic linkages. The acids may conta two, ee, four or more carboxyl groups. The open-chain portion of the molecule containing the sulfonyl radical or radicols may be further substituted with alieyclic, heterocycli-C or aromatic radicals which in turn may be substituted with noninterfering substituents, such as halogen atoms, alkoxy radicals, and the like. Illustrative examples of these acids @are beta,beta-sulfonyldipropionic acid, i. e., HOOC(CH2)2SO2(CH2)2COOH, gaMmagamma'-sulfonyldibutyric acid, gamma,gammal-sulfonyldihexanoic acid, 4,6-disufonylsuberic acid, i. e., HOOC(CI-L-)2SO2CI-I2SO2CI-r2COOH, I 4,7-disulfonylsebacie acid, 4,11- disulfonyltetratecanedioic acid, 4,7, 10-trisulfonyltridecanedioic acid, 3,6 - disulfonyl - 1,2,7-octanetricorboxylic acid, 2,5 - disulfonyl-1,3,6 - hexanetricarboxylic acid, 3 6-disulfonyloctanedioic acid, beta,beta'sul fonyid@ivaleric acid, 2-sulfonyl-1,3,5-- pent'anetri6arbGxSrlic acid, carboxy ben2yl-sulfonyl-meth.
[2]3 ane carboxylic acid, 1,2,3- tri(sulfonylethylearboxy) -propane, and beta,betasulfonyldichloropropionic acid. The preferred sulfur-containing acids to be used in producing the novel esters of the invention are the dicarboxylic acids containing not more than 28 carbon atoms and having from 1 to 3 non-adjacent methylene groups joined to carbon atoms in an open-chain portion of the acid molecule replaced by a sulfonyl radical, and the tricarboxylic acids containing not more than 28 carbon atoins and having from 1 to 3 nonad-jacent methylene groups joined to carbon atoms m an openchain portion of the acid moleculc replaced by a sulfonyl radical. Examples of the preferred acids are beta,beta'-sulfonyldipropionic acid, gamma,gamma'-sulfonyldicapric acid, 4,7-disulfonylsebacie, acid, 3,6-disulfonyl1,6-octanedioic acid, 4-sulfonyl-1,2,6- hexanetriboxylic acid, 2,4-disulfonyl-1,3,6-hexanetricarboxylic acid, and 2,4,6-trisulfonyl1,3,10-tetradecanetricarboxyli-c acid. Particular'@y preferred sulfur-containing acids are thedicarboxylic acids containing not more than 28 carbon atoms and having from I to 3 non-adjacent methylene groups joined to carbon atoms in an open-chain portion of the acid molecule replaced by sulfonyl radicals, one of said sulfonyl radicals preferably being not more than 8 carbon atoms from one of the said carbonyl groups. A special group of the above-described acids are those of the formula HOOC-Ri-SO2-R2-COOH wherein Ri is a divalent saturated aliphatic open-chainhydrocarbon radical, preferably containing from 1 to 8 carbon atoms, and R2 is a divalent hydrocarbon radical free of aliphatic unsaturation joined to the sulfonyl and carboxyl groups through aliphatic carbon atoms and preferably containing from I to 13 carbon atoms. Examples of these acids are beta,beta'-sulfonyldipropionic acid, gamma,g amma'-sulfonyldibutyric acid, gamma,gamma'-sulfonyldihexanoic acid, beta,beta'-su lfonyldibutanoic acid, beta,beta'- sulfonyldioctanoic acid, and carboxycyclohexylsulfoiiylbutanoic acid. The acids of the formula HOOC-R-SO2-R-SO2-R-COOH wherein R is a divalent saturated aliphatic openchain hydrocarbon radical, preferably containing 1 to 6 carbor. atoms, also present a particularly Preferred group, especially when the novel esters are to be used as plasticizers for the vinyl-type polymers. Examples of these preferred acids are 4,7-disulfonylsebacie acid, 4,11- disulfonyltetradecanedioic acid, 3,6-disulfonyl-1,7 -octanedicarboxylic acid, and 4,7- disulfonyl-2,5-heptadienedioic acid. The above-described sulfur-containing acids may be prepared by any suitable method. They are preferably prepared by oxidizing the corresponding thiopolycarboxylic acid. Complete oxidation of the thio group produces the sulfonyl acids. The oxidation of the thio acids may be effected by any of a large number of oxidizing agents, such as hydrogen peroxide, permanganates, bromides, fuming nitric acid, chromic acid, and perbenzoic acid. The oxidation may also be accompi,ished by treating the acids with molecular oxygen, preferably in the presence of catalysts. The amount of the oxidizing agent to be employed 2,640,848 4 will vary over a considerable range. As used tbroughout the specification the expression "chemical equivalent amount" refers to the amount of agent necessary to furnish one atom of oxygen for every thio linkage to be oxidized. It is generally desirable to react the thio acid with at least twice the chemical equivalent amount of oxidizing agent. Preferably, the thio acid and agent are reacted in chemically equivalent ratios 10 of 1:2 tol:2.5, respectively. The oxidation may be accomplished in the presence of solvents or diluents. Examples of suitable solvents and diluents are glacial acetic acid, acetone, benzene, toluene, xylene, and the 15 like, and mixtures thereof. The temperature employed during the oxidation may vary over a considerable range depending upon the type of reactants and oxidizing agents employed. It is generally desirable to 20 maintain the temperature between about 501 C. and 125' C. Cooling may be employed if necessary. Atn-ospheric, superatmospheric or subatmospheric pressures may be employed as desired. 2,5 The sulfonyl acids formed in the reaction mixture may be recovered therefrom by any of the conventional methods, such as extraction, distillation, fractional precipitation, and the like. The thio aci-ds used in the above-described process may be prepared by a variety of methods. 30 They may be prepared by reacting a halo-substituted monocarboxylic acid salt with an alkali metal sumde, such as sodium sulfide, or by reacting a sulfhydryl-substituted monocarboxylic acid salt with a halosubstituted monocarboxylic 3,3 acid salt. They may also be prepared by reacting hydrogen sulfide or an organic dithiol, such as 1,2-ethaneditbiol, with an unsaturated nitrile, such as acrylonitrile, in the presence of an activating agent, such as ultraviolet light, organic 40 peroxides, or basic catalysts, and subsequently hydrolyzing the nitrile. The reaction conditions for this latter method are described in detail hereinafter. The alcohols used in producing the novel esters -15 of the invention comprise the monohydric alcohols containing at least six carbon atoms and being free of aliphatic unsaturation. The expression "aliphatic unsaturation" refers to ethylenic or acetyleriie linkages contained between 50 two aliphatic carbon atoms. The alcohols may be aliphatic, alicylic, heterocyclic, or aromatic and may be substituted if desired with noninterfering substituents, such as the halogen atoms, alkoxy radicals, and the like. Examples of these alcohols are hexanol, isoheptanol, octanol, tertoctanol, 2-ethylhexanol, 2,5-dimethylheptanol, dodecanol, tetradecanol, pentadecanol, octadecanol, 3,5,8-triethyldodecanol, cyclohexanol, methylcyclohexanol, tert - butylcyclo60 hexanol, cyclohexylpropanol, octanediol monoacetate,- hexanediol monoethyl ether, benzyl alcohol, furfuryl alcohol, alpha-benzyl furfuryl alcohol, 2- imidazolemethanol, bromophenol, thiophenol, thiazanthenol, 3-bromooetanol, 5-meth65 oxydodecanol, naphthalenepropanol, and the like. The preferred alcohols to be used in producing the novel esters are the members of the group consisting of the aliphatic monohydric alcohols containing from 6 to 20 carbon atoms and the 70 aromatic mbnohydric alcohols containing from 6 to 20 carbon atoms, said alcohols being free of aliphatic unsaturation. Examples of these preferred alcohols are heptanol, 2 - ethyl - heptanol, decanol, cyclohexanol, methylcyclohexanol, 75 benzyl alcohol, diphenylcarbinol, and guaiacol.
[3]2iO4O,848 5 The particularly preferred alcohols are the saturated open-chain aliphatic monohydric alcohols containing from 8 to 15 carbon atoms, such as 2-butyloctanol, 2-ethylheptanol, 2-ethylhexanol@, octanol, decanol, 3,4-dibutylhexanol, pentadecanol, and 3,6,8- trimethyldecanol. The carbocyclic alcohols, i. e. the alicyclic alcohols and the aromatic alcohols containing from 6 to 15 carbon atoms, also present a preferred group, particularly when the novel esters are to be used as plasticizers for the vinyl-type polymers. Examples of the@e alcohols are cyclohexanol ' methylcyclohexanol, tert-butyleyelohexanol, benzyl alcohol, phenol, guaiacol, cyclohexylmethanol, and the like. The novel esters of the invention are theoreticaly derived by esterifying any of the abovedescribed sulfur-containing acids with one or a, mixture of two or more of the above-described alcohols. Illustrative examples of the novel esters are dihexyl beta, beta'-sulfonyldibutyrate, dioctyl beta,betal - sulf onyldipropionate, di - tert - butyleyclohexyl 3,6-disulfonylazelate, trioctyl 2-sulfonyl - 1,3,5 - pentanetricarboxylate, hexyl octyl beta,beta'-sulfonyidicaprate, diphenyl gamma,gamma' - sulfonydivalerate, trioetyl 3 6 disulfonyl - 1,2,7 - octanetricarboxylate, @ ethylhexyl decyl beta,beta'- sulfonyldichlorohexanate and dinonyl 4,7-disulfonyl -2,5-heptanedioate. The preferred esters of the invention, i. e., those prepared from the preferred sulfurcontaining acids and the preferred monohydric alcohols, may be exemplified by di-2- ethylhexyl beta,beta'-sulfonyldipropionate, dicyclohexyl beta,beta'-sulfonyldivalerate, trioetyl 3,6 - disulfonyl - 1,2,7octo,netricarboxylate, and dimethylcyclohexyl 4,7disul.fonyl-2,5-heptanedioate. ThE, novel esters of the invention may be prepared by a variety of methods. They MaY be prepared, for exan-iple, by reacting the acids containing the sulfonyl radical or radicals with the desi-red alcohol, by reacting an acid chloride of the sulfur-containing acids with the alcohol in pyridine, by an ester exchange reaction wherein ester derivatives of either the aforedescribed sulfur-containing acids or desired alcohols are reacted with the free alcohol or acid or their esters in the presence of an esterexciiange catalyst, or alternatively by reacting the corresdonding thio acid with the desired alcohol and subsequently oxidizing the thio acid ester to the desired sulfonyl form, or still further by reacting an unsatlirated acid with the desired alcohol, adding hydrogen sulfide or an organic polythiol thereto, and subsequently oxidizing the resulting thio-substituted ester to the desired sulfonyl form. The direct esterification of the sulfonyl radical or radicals with the desired alcohols, or the Psterification of the thio acids or the unsaturated o,cids with the desired alcohols, as described above, is preferably accomplished by heating the a;lcohols and acids together in the presence of an esterification catalyst and removing the water formed during the reaction, preferably by distillation. E, xamples of catalysts, that may be used for this type of reaction,are p-toluenesulfonic acid, ethylsulfonic acid, hydrobromig acid, chloroacetic acid, sulfuric acid, benzenesulfonic acid, formic acid, boron and silicon fluorides, acid salts, such as monosodium and monopotassium sulfates, and salts of strong 9@cids and weak bases, such as aluminum sulfate, zinc chloride, zinc sulfate, and the like. 6 over a wide range depending upon the particular type ofreactants, catalyst, and reaction conditions employed. In most cases, the amount of catalyst ,vill vary from 0.1% to 5% by weight of the reactants. The amount of acid and alcohol to be utilized in the reaction will vary over a considerable range depending upon the type of product desired. In general, the acids are reacted with at least a 10 chemical equivalent amount of the alcohol. As used throughout the specification and claims, the expression "chemical equivalent amount" is meant the amount of reactant necessary to furnish approximately one hydroxyl group for 15 every carboxyl group to be esterified. Preferably the acid and alcohol are reacted in chemical equivalent ratios varying from 1:1 to 1:2, respectively. The esterification may be accomplished in the 20 presence or absence of solvents or diluents. In case solvents or dilueiits are desired, organic compounds, such as benzene, tolvene, cyclohexane, xylene, and mixtures thereof, which do not interfere with the reaction, are generally pre2,r) ferred. The temperature employed in the esterification process may vary over a considerable range. In general, temperatures varying between about 701 C. and 150' C. are preferred. Particularly So preferred temperatures range from 80' C. to 100' C. Higher or lower temperatures may be utilized, however, if desired or necessary. Atmos@heric, superatmospheric, or subatmospheric pressures may be employed. 35 The separation of the esters formed in the reaction may be accomplished by any suitable means, such as extraction, distillation, fractional precipitation, and the like. If the esters are prepared by reacting a thio 4.o acid with the desired alcohol and oxidizing the resulting ester to the sulfonyl form, or by reacting an unsaturated acid with the alcohol, adding hydrogen sulfide or an organic polythiol, and subseqliently oxidizing the resulting thio ester, 4,,-) the oxidation of the thio linkage may be accomplished by the method described hereinabove for the preparation of the sulfonyl acids from the corresponding thio acids. The thio esters used in the above-described 50 process are preferably prepared by reacting hydrogen sulfide or an organic polythiol with an unsaturated ester in the presence of ultraviolet light, peroxide catalysts, or basic catalysts. The organic polythiols used in this reaction may be 55 exemplified by 1,2-ethanedithiol, 1,4-butanedithiol, 1,6-hexanedithiol, cyclohexanedithiol, 1-,2 3-propanetrithiol, and 1,7- decanedithiol. The u@;Aturated esters used in the reaction may be exemplified by cyclohexyl crotonate, octyl acrylGo ate, benzyl crotorate, dodecyl 4-butenoate, tetradecyl 4-heptenoate, and the like. Light rays that may be used for this addition reaction are p-referably those having wavelengths between 1800 Angstroms and 3500 Angstroms, 65 particularly those between 2000 and 3000 Angstroms. The peroxide catalyst rnay be illustrated by tertiary-butyl hydroperoxide, 2,2 -Iiis(tertiarybutylperoxy)butane, di-tertiary-butyl peroxide, acetyl peroxide, tertiary-butyl perbenzoate, and 70 the like. The basic catalysts may be exemplified by sodium hydroxide, potassium, apimonia, dibutyl amine, diethyl amine, and the like. The amount of the catalyst employed will vary over a considerable Tange. In most cases the amount The amount of the catalyst employed will vary 70 will generally vary from 0.1% to 4% by weight
[4]7 of the reactants. The reaction may be accomplished in the presence or absence of solvents or diluents. If solvents or diluents are employed, they should be organic compounds which are inert, such as benzene, toluene, xylene, and the like. The amount of reactants to be utilized in the addition reaction may vary considerably. It is generally preferred to react the hydrogen sulfide or organic polythiol with at least an equivalent amount of unsaturated ester, i. e., an amount of i ester sufflcient to furnish one unsaturated linkage for every thiol group. The temperatures utilized will vary depending upon the reactants and catalyst selected. In most cases, the temperature will range from 801 C. @to 200' C., wiih a preferred range varyin., from 90' C. to 150' C. Atmospheric, superatmospheric or subatmospheric pressures may be utilized. The thio esters may be recovered from the reaction mixture by any conventional method, such as distillation, fractional precipitation, extraction, and the like. The novel esters of the invention possess many unique properties which make them particularly useful and valuable in industry. They may be used, for example, as synthetic lubricating oils, asphalt adhesive agents, water-proofing agents for inorganic gel greases, as thickening agents or viscosity index improvers, tackifiers, solvents, rubber preservatives, vulcanizing accelerators, insecticidal and germicidal compositions, or additives therefor, additives for dye preparations, textile lubricants, wetting agents, dispersing agents for oils, polishes, protective waxes, and the like. They are particularly valuable as plasticizers for organic resinous compositions, such as cellulose nitrate, cellulose acetate, celltuose butyrate, cellulose acetobutyrate, and ethyl cellulose, the caseiil and other protein plastics, ligriin plastics, synthetic linear polyamides, phenol-aldehydes type resins, urea-aldehyde type Tesins, and the like. The novel esters are especially valuable as plasticizers for the vinyl-type polymers, such as polyvinyl chloride, and when used in this capacity Produce Plasticized compositions possessing many superior properties. Vinyl-type polymers that may be plasticized with the above-described compounds are the homopolymers, copolymers and interpolymers of the vinyl-type monomers. Vinyltype monomers include all those organic compounds containing at least one CH2=C< group in their molecule. Examples of the vinyl-type monomers are styrene, alphamethylstyrene, dichlorostyrene, vinyl naphthalene, vinyl phenol, acrylic acid and the alpha-alkyl substituted acrylic acids; the esters of these unsaturated acids, such as methyl acrylate, methyl methaerylate, butyl methacrylate, and prop,,,l @,,crylate; the vinylidene halides, such as vinylidene chloride, vinylidene bromide and vinylidene fluoride; the vinyl esters of the inorganic acids, such as the halogen acids and hydrocyanic acid, as vinyl chloride, vinyl bromide, acrylonitrile, and methacrylonitrile; the vinyl esters of the monocarboxylic acids, such as vinyl acetate, vinyl chloroacetate, vinyl benzoate, vi4yl valerate, and vinyl caproate; the vinyl esters of the polycarboxylic acids, such as divinyl succinate, divinyl adipate, vinyl allyl phthalate, vinyl methyl glutarate; the vinyl esters of the unsaturated acids, such as vinyl acrylate-, vinyl crotonate, and vinyl methaerylate. A preferred group of vinyl-type polymers to be plasticized with the esters are the polymers of the halogen-containing viiiyl-type monomers. Examples of this preferred group of polymers are polyvinyl chloride, polyvinyl bromide, polyvinylidene chloride, polyvinylidene bromide, copolymers of vinyl chloride and vinyl acetate, copolymers of vinyl chloride and vinylidene chloride, copolymers of allyl chloride and vinyl chlo:riCLe, copolymers of vinylidene chloride and vinyl acetate, copolymers of vinyl chloride and methyl methaerylate, and the like. Particularly preferred polymers to be plasticized with the novel esters of the invention are the vinyl halide polymers. The expression 'vinyl halide polymer" as used throughout the specification and claims refers to polymers containing a predominant quantity, i. e. at least 60 % by weight, of a vinyl halide, such as vinyl chloride and 15 vinyl bromide. Examples of these polymers are polyvinyl chloride, polyvinyl bromide, copolymers of vinyl chloride and vinyl acetate, copolymers of vinyl chloride and methyl methacrylate, and copolymers of vinyl bromide and vinyl propionate. ,o A single ester may, be used as the plasticizer, or a mixture of two or more of the compounds may be util,'Zed. In addition, the compounds may be used in combination with other plasticizers, such as dioetyl phthalate, dibutyl phthalate, tri,3 cresyl phosphate, and the like. The amount of the plasticizers to be incorporated with the above-described vinyl-type polymers may vary over a considerable range depending upon the particular type of polymer to be ubilized, the intended use of the compounded resin, etc. In most cases the amount of the plasticizer will vary from about 20 to 150 parts by weight for every 100 parts by weight of polymer. A more preferred range comprises 40 parts to 75 parts by weight of plasticizer for every 100 parts by weight of resin. alid pigments such as whiting, channel black, clay, gum rosin, silica and others, and stabilizers, such as litharge, some oxides of bismuth and barium types, and some silicates may also be added to the polymer along with the novel compounds of the invention. The polymer and plasticizer may be compounded together by means of conventional equipinent such as mills of the heated roll type or in45 ternal mixers. The plasticizer and other compounding ingredients, such as fillers and stabilizers, are worked into the vinyl polymer so that they are thoroughly dispersed therein by means of such equipment, and the resultant composi50 tion then molded, extruded or otherwise formed ir-to articles of the desired shape by conventional procedure. To illustrate the manner in which the invention riay be carried out, the following examples 5;5 are given. It is to be understood, however, that the examples are for the purpose of illustration and the invention is not to be regarded as limited to any of the specific compounds or conditions recited therein. Unless otherwise specified, parts 6o dese-ribed in the examples are parts by weight. Volatility of the plasticized composition disclosed in the folloviin,- examples was determined on compression molded discs two inches in diameter aiid 0.045 incli thick. Th-- discs were con65 ditioned for one hour at 100' C., weighed, placed back in the oven for 100 hours at 1001 C., and rewei,-hed. The difference in weight represents the amount of plasticizer lost. The loss of plasticizer was then compared with the loss of a 70 similar resin plasticized with dioctyl phthalate, the latter being arbitrarily assigned a value of unity. Example I 75 About 98 parts of 2-ethylhexyl crotonate, 10.2
[5]@'9 parts of hydrogen sulfide aiid 3.7 parts of nbutyl amine were placed in a stginless steel borD.T.@ and hea,ted to a tempe.-a'uure of 3.15' C. for 48 hours. The reaction mixture was then d-istilled to produce di(2-ethylhexyl) beta,beta'-thiodi- 5 butyrate having the follo,.vina physical properties: n 20 1.4656: D. P. at I @00- r@'.-20'@' D About 17 part;s of a 30% solution of hydrogen peroxide was slowly added to a mixture of 6@@ parts of the di(2-ethylhexyl) beta,beta'-thiodi- lo butyrate and 200 parts of glacial acetic acid, The temperatur e was between 25' C. and 30' C. After the exothermic reaction had ceased, another 17 parts of peroxide solution was added and the combined mixture allowed to stand at rooni tem- 15 perature. two days. 300 parts of benzene was then added and the solution washed several times with water to remove acetic acid. Finally the benzene and traces of @,.-,7ater were reilov@--d by topping to a, kettle temp@l@ature of 1.25' C. under 20 2 mrn. pressure. The resulting product ,,7as di(2- ethylhexyl) beta,beta'-sulfonyldibutyrate, a, light yellow viscous liquid having a refractive index Of nD 20 1.4659; S, percent weight found 7.0(9), cale. 6.93. 25 Example II About 92 parts of 2-ethylhexyl acrylate, 10.2 parts of hydrogen sul-fide and 3.7 parts of n-butyl amine were placed in a stainless steel bomb and 30 heated to a temperature of 100, C. to 1151 C. for about 4,8 hours, The reaction mixture was t3len distilled to produce di(2-ethylhexyl,) beta,beta,'- thiodipropi onate. 17 parts of a 30@/,, solution of hydrop,,eii per- P5 oxide was slowly added to a, mixture of 58 Do,,rts of t-he di(2-ethylhexyl) beta,betg,'-tliio-,I,.P-Opionate and 200 parts of glacial acetic ,teid. After @the exothermic reaction had ceased. another '.17 1 parts of peroxide solution was addec', ,i,j.-id t'l(' 1(1 combined mixture allowed to stand at roo-rn temperature for two days. 300 parts of benzene @vas then added and the solution washed with water to remove the acetic acid. The mixture was then distilled to produce di(2-ethylhexyl) beta,beta'- sulfonyldipr opionate, a viscous liquid having a 45 refractive index of nD 20 1.4656. Example III About 89 parts of cyclohexyl crotonate, 10.2 parts of hydrogen sulfide and 3.7 parts of n-butyl amine are heated to a temperature between 1001 C. and 115, C. for about 48 hours. The reaction niixture is then distilled to produce dicyclohexyl beta,beta'-thiodibutyrate. 17 parts c-,-F a 30% solution of hydrogen peroxide is then slowly added to a mixture of about 55 parts of dicyclohexyl beta,])eta'-thiodibutyrate and 200 parts of glacial acetic acid. After the exothermic reaction has ceased, aliother 17 parts of peroxide solution is added and the combined mixture allowed to stand for about two days. The mixture is then washed as shown in Example I and distilled to produce dicyclohexyl beta,beta'- sulfonyldib utyrate. Examl)le IV 65 About 214 parts of 2-ethylhexyl acrylate, 94 parts of ethonedithiol and 4 parts of piperidine are heated at 1001 C. for several hours. e reaction mixture is then washed several times with -i 0 dilute sodium hydroxide and distilled to produce di(2-ethylhexyl) 4,7-dithiasebacate. 30 parts of a 30% solution of hydrogen peroxide is then added to a mixture o-f about 60 parts of the di(2-ethylhexyl) 4,7-dithiasebacate and 300 5 !Z,,($402848 1( parts of glacial acetic acid. After the exothermic reaction has ceased, another 30 parts of peroxide solution is added and the combined mixture allowed to stand for several days. The mixture is then washed as shown in Example I and distilled to produce di(2- ethylhexyl) 1,7-disulfonylsebacate. Example V About 98 parts of benzyl acrylate, 10.2 parts of hydrogen sulfide and 3.7 parts of n-butyl amine are heated to a temperature between 100' C. and '115' C. for 50 hours. The reaction n)ixture is then distilled to produce dibenzylbeta,beta'thiodipropionate. 17 parts of a 30 % solution of hydrogen peroxide is added to a mixture of about 60 parts of the dibenzyl beta,beta'-thiodipropionate and 200 parts of glacial acetic acid. After the exothermic reaction has ceased, ancther 17 parts of peroxide solution is added and the combined mixture allowed to stand for several days. The mixture is then washed and distilled to produce dibenzyl beta,beta'-sulfon yldipropionate. Example VI About 250 parts of oetyl methacrylate, 144 parts of hexanedithiol and 4 parts of piperidine are heated at 100, C. for several hours. The reaction mixture is then washed several times with dilute sodium hydroxide and distilled to produce dioctyl 2,13- dimethyl-4,11-dithiatetradecanedioate. 30 parts of a 30% solution of hydrogen peroxide is added to a mixture of about 80 parts of the dioctyl 2,13-dimethyl - 4,11 - dithiatetradecanedioate and 300 parts of glacial acetic acid. After the exothermic reaction has ceased, another 30 parts of peroxide solution is added and the combined mixture allowed to stand for several days. The mixture is then washed as shown in Example I and distilled to produce dioctyl 2,'13- dimethyl4,11-disulfonyltetradecanedioate. Bxample VII About 100 parts of polyvinyl chloride was compounded with 50 parts of di-2-ethylhexyl beta,beta'-sulfonyldipropionate produced in Example II by mixing the two ingredients together with 2 parts (per 100 parts of polymer) of a trade stabilizer, milling the mixtur6 together on a roll mill at a temperature between 1301 C. and 150' C. and then molding the resulting sheets at 160' C. for two minutes. The resulting sheets had no unpleasant odor, possessed excellent tensile strength and flexibility over a wide range of conditions, and possessed good color and heat stability. The pla-sticized composition showed a volatility of only 0.3 that of a similar composition plasticized with dioctyl phthalate. A similar composilion plasticized with dibutyl alph a,alpha'-sulfonyldiacetate had a grayish tinge, unpleasant odor and a volatility of over 5 times that of a similar composition containing dioetyl phthalate. Example VIII About 100 parts of polyvinyl chloride was compounded with 50 parts of di-2-ethylhexyl beta,e a'-sulfonyldibutyrate by the method disclosed in Example VII. The resulting sheet possessed good tensile strength and flexibility over a wide range of conditions, and had good color and heat stability. The plasticized composition showed a volatility of only 0.2 that of a similar composition plasticized with dioetyl phthalate.
[6]2,640,848 Example IX About 100 Parts of polyvinyi chloride is com.pounded with 50 parts of dicyclohexyl betabeta'- sulfonyldibutyrate by the method disclosed in Example VIII. The resulting sheet possesses low 5 volatility and good tensile strength. Example X About 100 parts of a copolymer of 95% vinyl chloride and 5% vinyl acetate is compounded u @vith 50 parts of di(2-ethylhexyl) 4,7-disulfonylsebacate by the method disclosed in Example Vii. The resulting sheet possesses good tensile strength and flexibility over a wide range of conditions, and undergoes little change in shape or composition when exposed to high temperatures. We
