Polyvinyl chloride plasticized with methyl esters of organic sulfonic acid oligomer
United States Patent 11 1 1111 3,875,102 Straus et al. 1 Apr. 1, 1975 POLYVINYL CHLORIDE PLASTICIZED [58] Field of Search 260/513 R. 30.8 R  
 WITH METHYL ESTERS OF ORGANIC SULFONIC ACID OLIGOMER [56] References Cited [75] Inventors: Alan E. Straus, El Cerrito; William UNITED STATES PATENTS A. Sweeney, Larkspur; Ralph House, 3.535.251 10/1970 Brenschcde et a1 260/308 R El Sobrante; Samuel H. Sharman, KenSingtOn. 1111 O Clllif- Primary E.\&#39;uminer-Lewis T. J&#39;acobs [73] Assignee: Chevron Research Company San Atrornqv, Agent, or FirmG. F. Magdeburger; John Francisco, Calif. Stoner [22] Filed: July 28, 1972 [57] ABSTRACT [21] App]. No.: 279,430 Organic disulfonic acids are produced by heating a sulfonate monomer at a temperature above 110C. in 7 Related Apfhcauon 9 the substantial absence of water. Olefin sulfonation g z y rg f 196 product mixtures, hydroxyalkane sulfonic acids, a]-  
  kane sultones, alkene sulfonic acids and mixtures 52 us. Cl. H 260/308 R 260/513 thereof Oligomerized under I51 Int. Cl. C08f 45/46 2 Claims, N0 Drawings POLYVINYL CHLORIDE PLASTICIZED WITH METHYL ESTERS OF ORGANIC SULFONIC ACID OLIGOMER This is a division of application Ser. No. 858,097 filed Sept. 15, 1969, now U.S. Pat. No. 3,721,707, issued Mar. 20, 1973.  
 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a process for the production of organic sulfonic acid oligomers and to the novel compositions produced in the process, particularly sulfonic acid oligomers from straight chain precursor compounds.  
 2. Descrpition of the Prior Art It is known to prepare organic sulfonic acids by the reaction of sulfur trioxide with mono-olefinic hydrocarbons in the liquid phase at a temperature below about 100C, usually below about 50C.. by either contacting the olefin with attenuated sulfur trioxide, that is with gaseous sulfur trioxide which has been diluted with a relatively inert gas, usually air, or with sulfur trioxide which is modified by complexing with an organic ether, acid, acid anhydride, a phosphate ester, or the like. In general, the resulting sulfonate reaction product mixture only contains a minor amount of organic sulfonic acid, usually alkene sulfonic acid, and a major amount of alkane sultones. Additional sulfonic acid can be obtained by hydrolysis of the sulfonation reaction mixture by treatment with aqueous caustic or aqueous mineral acid. When aqueous caustic is employed, the resulting product is a complex mixture which is mainly alkene sulfonate and hydroxyalkane sulfonate. Where acid is employed, the product is a mixture of alkene sulfonic acid and hydroxyalkane sulfonic acid. In the case of the caustic hydrolysate the corresponding sulfonic acid can be obtained by acidification with strong mineral acid and extraction with a suitable organic solvent. The hydroxy sulfonic acids, however, readily revert under acid conditions to sultones with mild heating.  
  The neutralized sulfonic acids obtained by the use of alpha olefins are excellent surface active agents, and are particularly useful for the production of foamed well circulation fluids. However, aqueous concentrates of these materials tend to solidify and separate into solid and liquid phase mixtures under the temperature conditions encountered in the field.  
  A more direct process for the production of organic sulfonic acids is desirable for reasons of cost.  
  A process for the production of organic sulfonic acids substantially free of hydroxy substituents is desirable in order to avoid sultone formation.  
  An aqueous organic sulfonate detergent concentrate which does not separate into a mixture of solid and/or liquid phases or does so only at very low temperatures is desirable for use in the foamed well circulation fluid art. [See, for example, copending U.S. application Ser. No. 704,832, filed Feb. 12, 1968.]  
 SUMMARY OF THE INVENTION It has now been found that an organic sulfonic acid oligomer mixture can be prepared by heating in the liquid phase a feed containing one or more compounds having a carbon atom content in the range from about 5 to 1,000 carbon atoms of the types and formulas:  
  l a. sultones, R (OSO b. hydroxysulfonic acids, R (SO H) (OH) in which R is hydrogen or a monovalent hydrocarbon radical, and R is a divalent hydrocarbon radical, and in which the R and R groups contain no nonaromatic carbon-carbon doubleor triple-bond unsaturation. The heating is continued for a period of time sufficient for at least a significant conversion of the feed, a period which is usually in the range from about 1 minute to 25 hours.  
  Surprisingly, when the feed is heated above about C. in the substantial absence of water. i.e., where the water content of the heated mixture is less than about 5-10 percent by weight, the oligomerization reaction, a dimerization and/or intercondensation, occurs which results in the production ofa mixture of molecular species having an average molecular weight which is approximately double that of the original feed. The resulting oligomer product appears to be mainly a mixture of novel disulfonic acids of the formula in which the several R groups are the same or different alkanediyl radicals and Y is a radical of the group 1, l ,2,2-ethanetetrayl, l,2,4,5-benzenetetrayl, or l,2,4,5-cyclohexanetetrayl. The total number of carbon atoms contained by these disulfonic acid oligomers is equal to the sum of the carbon atom contents of the two precursor monomers participating in the oligomerization reaction. Structural representations of the foregoing oligomers include the following:  
 HR-CH-RSO it HR-CH-RSO3H,  
 nR-- RSO a s 3 H0335- RH and HR--- aso a HR- BS0311 i.e., including head-to-head and head-to-tail oligomerization of the monomers.  
  In view of the difunctionality of the subject oligomers, they are particularly useful for the production of linear polymers, particularly those obtainable from the disulfonyl halide derivatives of the subject oligomers, for example:  
  1. R(SO CI) H N(CH NI-l polysulfonamide polymer. Otherpolyfunctional comonomers, such as organic diols, polyols, etc., may also be employed for the preparation of useful polymers and resins from the oligomeric polysulfonates of the instant invention.  
 DESCRIPTION OF THE INVENTION In a preferred embodiment of the present invention a mixture of oligomerizable compounds is used. namely the crude reaction product mixture resulting from sulfonating an n-alkene, for example l-hexadecene, with vaporized sulfur trioxide which has been diluted with air. When the conversion of the olefin to sulfonute is substantially complete (requires about 1.20 mols of S per mol of olefin), the product mixture is heated to 155l 60C. and maintained at this temperature for l-1.5 hours. Infrared and/or nuclear magnetic resonance (NMR) spectra analyses demonstrate that the resulting mixture contains little or no hexadecene sulfonic acid, hydroxyhexadecane sulfonic acid or hexadecane sultone,.the foregoing being the principal components of the sulfonated hexadecene feed.  
  Molecular weight and other characterizing determinations demonstrate:  
 1. that the product has a molecular weight corresponding to a C -disulfonic acid; 2. the product is a molecular mixture of which about mol percent contains a benzene ring, another substantial fraction contains a cyclohexane ring, and a third substantial fraction is a carbon-carbon bond-bridged hexadecyl dimer containing no unsaturation; and  
 3. the oligomeric disulfonic acid mixture per se is a useful foaming agent as are likewise the water soluble salts of the acid.  
  In view of the nature of the product composition, it is clear that a number of chemical reactions are occurring in the present process (including dimerization by reaction between two like monomers). intercondensation (reaction between dissimilar monomers, i.e., homologs), acyclic cyclization, aromatization and intra molecular transfer of hydrogen.  
  The temperature required to effect the oligomerization of the process is in the range above about 1 10C. As the temperature is increased, the reaction rate becomes faster. Preferred temperatures are in the range l-200C. Higher temperatures may be employed advantageously provided that carbonization and degradation of the feed does not become a problem, a matter which varies depending upon the particular feed and usually occurs appreciably in the range 250300C.  
  The course and degree of completion of the present oligomerization reaction is conveniently followed by spectral analysis methods, particularly nuclear magnetic resonance (NMR) spectra of particular hydrogen atoms of the feed and product mixture. In the course of the reaction the following functional groups are eliminated from the product: (1) the sultone groups, (2) the carbon-carbon olefinic double bond unsaturation, and (3) the alkanol hydroxy groups; thus the adsorption arising from: l protons alpha to the sultone CO bond (usually in the range 4.4-4.6 ppm), (2) vinyl protons (usually in the range 5.0-5.9 ppm), and (3) protons alpha to the C0 bond of alkanol groups (usually in the range 3.4-3.7 ppm) decrease as the re action proceeds and approach or become zero when conversion is complete. Similarly, characteristic adsorptions of the aforementioned functional groups of the feed and product mixtures in the infared spectrum may also be conveniently employed to follow the conversion. Thus, the 1,3-sultones absorb significantly at l,330-l,350, 1,190, 1,155, 1,000, 940, 815-880 and 620 cm&#34;. The 1-4 sultones absorb significantly at l,330l,360, 1,160, 895, 810-825 and 530 cm, Vinyl unsaturated sulfonic acids adsorb significantly at 1,700,  
 [2134-3] ppm 4.4-4.6 ppm) 5.()5.9 ppm} EZ(3.43.7 ppm 4.4-4.6 ppm) 5.05.9 ppm] product mlxwre feed is a measure of the uncoverted feed. Conversely, as used herein, when the foregoing ratio has decreased to less than 0.90 to 1, then by definition a significant conversion of feed to oligomer product has occurred. Similar comparisons may be used employing the other characteristics adsorbances noted above.  
  In addition to the foregoing characteristic spectral adsorbances, as noted above, disulfonic acids containing benzene rings and cyclohexane rings are produced in the subject reaction. This results in new or additional characteristic spectral adsorbances arising, for example, from hydrogen attached to a carbon atom which is a part of a benzene nucleus. These adsorbances, particularly in the NMR spectra, may also be employed to mark the degree of completion of the process.  
  By oligomerization, as used herein, is meant dimerization of like monomers and intercondensation of unlike monomers.  
  By longest straight chain of the compound, as used herein, is meant the determination as in conventional practice which is employed in the naming of organic compounds.  
  The length of time required for conversion of the feed to oligomer varies depending upon the monomer or monomeric mixture employed and the temperature of the heating. For example, using an n-C,,-, alpha olefin sulfonation product feed, the following representative time-temperature relationship was noted:  
 Thus, in view of the foregoing, the time required for substantially complete conversion percent plus), in general, will be in the range from about 0.1 to 30-50 hours and for the preferred temperature range; C. to l70-200C., in the range from about 0.1 to 5 hours. Where partial conversions are desired, relatively shorter reaction periods are employed.  
  An induction period for the oligomerization which varies depending upon the particular feed is especially notable at reaction temperatures in the range below about 130-l55C. Thus at 120C. this period may be as much as l-2 hours. As this temperature is raised, the induction period becomes shorter and above about C. is scarcely, if at all, appreciable. The use of the aforedescribed spectral analysis technique as a means of following the course of the reaction disposes of any ambiguity which might arise in view of the induction phenomenon.  
  Usually the process of the invention is effected more advantageously in the absence of inert diluents, for example saturated hydrocarbons or mixtures thereof, but these may be employed to advantage. for example where heat exchange or temperature control is a problem.  
  Strong mineral acid appears to promote the instant oligomerization reaction, particularly in the case of the sultone feed compounds. 1n the case of the preferred sulfur trioxideolefin reaction mixture feeds, from 15 weight percent of sulfuric acid is ordinarily present and the presence of additional mineral acid does not appear to improve the rate of the reaction. However, the crude oligomerization reaction product mixtures ordinarily are quite dark colored and the presence of phosphoric acid in the heated mixture usually reduces the color. Sulfuric acid is preferred.  
  A wide variety of bifunctional organic compounds are suitable alone or in admixture as feeds for the present oligomerization reaction. They must contain at least about 5 nonaromatic carbon atoms per molecule, a sulfonate functional group, i.e., SO;;-, and one of the following: (1) a carbon-carbon double-bond. i.e., CH=CH-; (2) an alkanol hydroxy group. or a sulfonate ester group of which the above sulfonate group is a component, i.e, a sultone. and the functional groups must be substituents attached to non-aromatic carbon atoms with the balance being carbon and/or hydrogen. For practical purposes, the feed compounds will usually contain less than about 1,000 carbon atoms per molecule, and preferably less than about 50. More preferably the feed compounds have straight chain carbon skeletons and a carbon atom content in the range 5 to 30.  
  Representative classes of compounds suitable for use as feeds for the subject process include sultones, R (O- S hydroxy sulfonic acids. R (OH)( --SO H); and unsaturated sulfonic acids, R[R (CH=CH-)]- (SO;,H) in which R is hydrogen or a monovalent hydrocarbon radical and R is a divalent hydrocarbon radical, the feed compound(s) having a carbon atom content in the range from about 5 to 1,000 and containing no non-aromatic carbon-carbon double or carboncarbon triple bond unsaturation, and mixtures thereof. Preferred representative classes of feeds for the process herein are of the formulas a. RCEH(CH CHRSO in which .r is in the range O3, inclusive, and v is in the range O-n, with n being a number which is 4 less than the number of carbon atoms in the longest straight chain of the compound which contains the -SO H group as a substituent, and in which the R groups may be the same or different and are hydrogen or an alkyl group. mixtures of these classes and/or homologs are suitable feeds.  
  Preferred process feeds for use herein, for reasons of cost and availability, are the crude reaction product mixtures obtained by the sulfonation ofa mono-olefmic hydrocarbon feed using sulfur trioxide as known in the art [cfU.S. Pat. Nos. 2,061,617; 2,094,451; 2,572,605;  
 3.44.191, etc., as well as 1nd. and Eng. Prod. Research and Development, Volume 2, No. 3, pp. 229-231 1963)]. Briefly, in sulfur trioxide sulfonations the liquid olefin, either neat or dissolved in an inert medium. is contacted with from about 0.5 to 1.5, usually from about 0.8 to 1.3. mols of sulfur trioxide. The sulfur trioxide is added in a variety of ways:  
 1. vaporized and diluted with an inert gas, usually air;  
 2. complexed with an organic compound, for example dioxane, acetic acid or anhydride, etc.; or 3. as a solute in an inert medium, for example liquid sulfur dioxide, hexane, etc.  
 Since the olefin sulfonation reaction is exothermic, the reaction mixture temperature is generally maintained below about C., usually below 50C., by a cooling means. Somewhat higher local temperatures (as high as C.) usually prevail briefly at the zone of initial contacting of the reactants where air-sulfur trioxide sulfonation mixtures are employed. ln these reactions, mono-olefinc hydrocarbons containing at least one allylic hydrogen, i.e.,  
 are in general sulfonatable by the use of sulfur trioxide and although actual crude or processed product mixtures vary depending upon the particular combination of process variable employed, the product is in general a satisfactory feed for the instant oligomerization process provided that the water content of the feed is less than 5-10 weight percent. Excess water, if present, can be readily removed by conventional drying means.  
  Representative feeds satisfactory for use in the present oligomerization process include the sulfur trioxideolefin sulfonates derived from sulfonatable monoolefinic hydrocarbons such as hexadecene- 1, heptadecone-2, octadecene-3, hexene-l, ethylene-growth olefins, cracked wax alpha-olefins of the C -C molecular range and fractions thereof; olefins obtained by dehydrohalogenation of hydrocarbon halides; internal olefins obtained by partial or complete double-bond isomerization, i.e., partial or complete equilibration; pentacontene, tetracontene, triacontene, eicosene; substituted olefins such as 9-methyldecene-l, 8-cyclohexylundecene-Z, l0-phenyldecene-3, 7,8,9,l0-tetramethylundecene-l, 19-methy1eicosene, 19-ethyleicosene- 5, 4-isopropylpentadecene-1, 7-methyloctene-l; dimers and trimers (oligomers) of lower substantially straight chain olefins such as 2-butyloctene-1, 2-hexy1- decene-l; and the like mono-olefinic hydrocarbons.  
  Representative unsaturated hydrocarbon sulfonic acids suitable for use herein include hexadecene sulfonic (all isomers singly or in admixture), n-C,,C alkene sulfonic (molecular mixtures, fractions thereof and/or isomeric mixtures), n-hexane sulfonic, l lmethyl-1-sulfonic-dodecene-3, 6-cyclohexyll sulfonic-hexene-Z, 6-phenyl-1-sulfonic-heptene-4, eicosene sulfonic, pentacontene sulfonic, and the like acids.  
  Representative hydroxyalkane sulfonic acids suitable for use herein include 4-hydroxyoctadecane-l-sulfonic acid, 5-hydroxyoctane-3-sulfonic acid, l9-methyl-4- hydroxyeicosane- 1 -sulfonic acid, 7,8,9,10-tetramethyl- 5-hydroxyundecane-2-sulfonic acid, 6-cyclohexyl-4- hydroxy-heptane-l-sulfonic acid, 9-hydroxydecane-l sulfonic acid, 4-isopropyl-3-hydroxypentadecane-lsulfonic acid, l6-phenyl-3-hydroxyheptadecane-Z- sulfonic acid, -hydroxypentacontane-l-sulfonic acid, 4-hydroxy-tetracontane-2-sulfonic acid, 3- hydroxytriacontane-l-sulfonic acid; l8-hydroxyeicosane-2-sulfonic acid. 4- hydroxycyclohexane-l-sulfonic acid, and the like hydroxy-sulfonic acids.  
  Representative suitable feeds for use herein include sultones of the corresponding hydroxysulfonic acids. i.e., beta-, gamma-, deltaand epsilon-sultones of 2-. 3-. 4-, and S-hydroxyalkane sulfonic acids such as 2- hydroxyoctadecane-l-sulfonic 6-hydroxyeicosane-Z- sulfonic. 6-hydroxy-l l-phenyl-heptadecane-3-sulfonic. S-hydroxyhexane-l-sulfonic, 3-hydroxynonadecane-1- sulfonic, 4-hydroxy-ll-methyltetradecane-8-sulfonic, 3-hydroxyoctadecane- 1 -sulfonic. 4- hydroxypentadecane-Z-sulfonic. 4-hydroxytridecanel-sulfonic, 3-hydroxynonane-l-sulfonic, 9-cyclohexyl- 4-hydroxydecane-l-sulfonic, 4-hydroxypentacontanel-sulfonic, lO-phenyl-3-hydroxydecane-6-sulfonic, 8- isopropyl-4-hydroxyhexadecanel -sulfonic, 4- hydroxycyclohexane-l-sulfonic, and the like acids.  
 EXAMPLES The following examples further illustrate the invention.  
 Example 1: Sulfonation of l-Hexadecene The sulfonation unit consisted ofa 5 mm. ID. 3-foot,  
 jacketed falling film reactor equipped with an inlet weir for the olefin feed, a central 3 mm. O.D. sulfur trioxideair inlet tube, followed by a l-% inch by 4 inch post reactor tube. This reactor was continuously charged with l-hexadecene at a rate of 4.36 grams/min. Simultaneously there was added 1.87 grams/min. of 50;, diluted to 5% by weight in air (an olefin/S0 mol ratio of 1.2/1 The temperature of the outer surface of the reactor wall was maintained in the range of 45to 65C. by circulating cooling water in the jacket. The sulfonation product was collected and chilled to 0C. over a period of 2 hours. The product weighed 739 grams.  
  The infra-red (IR) spectrum of this reaction product showed the presence of both sultone and sulfonic acid. The 1,3-sultone absorbs at l,330-l,350, 1,190, 1,155, 1,000, 940, 815-800, and 620 cm. The 1,4-sultone absorbs at l,330l,360. 1,160, 895, 810-825, and 530 cm&#34;. Unsaturated sulfonic acid absorbs at 1,700, 1,165, 1,040, 965 and 910 cm. The above peaks were present.  
  The NMR spectrum also showed that the product was a mixture of sultones and unsaturated sulfonic acids. Protons beta to sulfonate in the sultones asborb at 2.1-2.6 ppml; those alpha to sulfonate in the sultones absorb at 2.8-3.2 ppm.; the protonalpha to the sultone C-O bond absorbs at 4.4-4.6 ppm; vinyl protons absorb at 5.0-5.9 ppm. All these peaks were present.  
  A 10 g. portion of the crude acid/sultone product was analyzed by cold neutralization (room temperature) with 13 millimoles of NaOH in aqueous alcohol followed by complete hydrolysis and&#39;neutralization at the presence of about 16% dior polysulfonates. The IR spectrum of this salt showed the typical bands at 1,180-1,200, 1,065, 795, 620 and 530 cm for a sulfonate salt plus a band at 965 cm from trans doublebonds.  
 Example 2: Oligomerization of the Hexadecene-SO Reaction Prdouct The acid reaction product from Example 1, 50 grams, was heated in a round bottomed flask at l50-l 53C. for 2% hours. At the end of this time, the viscosity of the heated material was considerably greater than that of the starting material.  
  An infra-red spectrum showed strong adsorptions at 1,700, 1,165, 1,040, 910 cm, all of which are typical of aliphatic sulfonic acids. The absence of adsorption bands at l,330-1,360, 895 and 810-880 cm showed that the sultone originally present in the feed stock had all been converted. The absence of a 965 cm adsorption band showed that there were no 1,2-disubstituted double bonds, i.e., all alkene-sulfonic acid was converted.  
  A nuclear magnetic resonance (NMR) spectrum had adsorption at 2.9-3.2 ppm, typical of aliphatic sulfonic acids. The absence of any bonds at 44-46 ppm and at 5.0-5.9 ppm also indicated complete conversion of the sultone and the absence of any 1,2-disubstituted double bonds, respectively.  
  A neutralization equivalent analysis required mols of base per gram of product.  
  The product was shown to have 2.3% water by a Karl Fisher titration.  
  The remainder of the product was converted to the sodium salt and was then desalted by precipitation from aqueous ethanol and deoiled by 5 extractions of this solution with petroleum ether. The precipitate was analyzed for Na SO and the extract was concentrated. This procedure showned the presence of 1.5% (wt.) oil and 0.4% sodium sulfate in the reaction mixture. The l.R. spectrum of the sulfonate salt was typical of the IR spectrum of olefin sulfonate salts, except there was no adsorption at 965 cm&#34;, i.e., there were no double bonds of the trans configuration.  
 Example 3: Esterification of the Oligomerization Product of Example 2 A portion of the product of Example 2, 5.00 grams, was dissolved in about 250 ml of diethyl ether. Then diazomethane formed by the decomposition of N-methyl- N-nitroso-p-toluene-sulfonamide [Reference: Rec. Trav. Chem. 73, 229 (1954)] was bubbled into the ether solution until the solution had a persistent yellow color. This solution was filtered to give 0.08 grams of an insoluble residue. Then the ether was removed from the filtrate by evaporation to give 5.26 grams of a viscous brown liquid. Infra-red and NMR&#39;analyses were run on this ester. The infra-red spectrum showed adsorption bands at 1,360, 1,170, and 995 cm, all of which are characteristic of methyl aliphatic sulfonate esters. There were no noticeable adsorptions characteristic of sultone or of trans olefinic double bonds in the ester. There were no hydroxyl adsorption bands at 3,200-3,700 cm. There were no ether adsorption bands at 1,060-1,l50 cm.  
  The molecular weight of the oligomer ester was found to be 627 by thermoelectric measurement of vapor pressure (Reference: ASTM D 2503-67), and  
 the highest mass peak obtained from a mass spectral analysis was 638 mass units.  
 Example 4: Preparation and Separation of sO -Hexadecene Sulfonation Product A l-hexadecene-SO reaction product was prepared as in Example 1 except that less 50;, 1.20 g/min.) was used, resulting in an SO /olefin mole ratio of 0.77/1. The product was collected in about 4 volumes of npentate. As in Example 1, a portion ofthis product was analyzed by neutralization, hydrolysis, desalting. deoiling and foam fractionation to show that the original sulfonation product contained about 50% sultone, 2471 sulfonic acid, 1% disulfonate. and 25 mole unreacted olefin.  
  Another portion (50 ml.) of the above pentane solu tion was filtered at room temperature to recover 0.66 g. of crystalline hexadecane-l,3-sultone. and then cooled in an ice bath and refiltered to recover another 100 g. of hexadeeanel ,3-sultone. The remaining pentane filtrate was mixed with 21 ml. H and 75 ml. acetone and extracted five times with n-pentane to give another 4.0 g. of sultone (mixed with 2.4 g. unreacted olefin). The sultone fractions were combined.  
  The aqueous-acetone layer which contained the sulfonic acid fraction of the product was stripped of solvents at 40-45C. under vacuum to give 2.85 g. of viscous acid identified as hexadecane sulfonic acid on the basis of an IR spectrum which showed the presence of trans olefinic double bond (965 cm) and the absence of sultones (no 830 and 530 cm bands).  
 Example 5: Dimerization of Hexadecene Sulfonic Acid The sulfonic acid prepared in Example 4 1.42 g) was heated at 160C. for 2 hours. The reaction product had 1R and NMR spectra. which for all practical purposes was identical to that of the acid product of Example 2.  
 Example 6: Dimerization of Hexadecanel,3-Sultone Hexadecane-l.3-sultone g, twice recrystallized from petroleum ether) was heated for 2 hours at 157-l87C. The IR and NMR spectra were essentially identical to that of the acid product of Example 2. The oligomeric acid was methylated as in Example 3. Carhon-hydrogen analyses on the methyl ester were 63.87: C. 10.52% H. Theoretical for C H s O is 64.10% C,  
  The NMR spectrum of the methyl ester showed adsorption at 6.6-7.0 ppm corresponding to the presence of substantial amounts of hydrogen atoms bonded to aromatic ring carbon atoms. Assuming a tetrasubstituted aromatic ring. this corresponds to about mol percent of the product: similar adsorptions were observed in the NMR spectra of the products of Example 2. 3 and 5.  
 Example 7: oligomerization of SO -Octene-l Sulfonate Example 1. 2 and 3 were repeated except that the lolefin used was loetene and the sulfonation mole ratio was 0.25 moles per mole of olefin. The excess octene was removed from the sulfonation product under vacuum at 4045C. The oligomerization was conducted for 2 hours at ll64C. IR and NMR spectra of the acid and methyl ester were the same as obtained for the l-hexadecene product except for the effect of the shorter alkyl chain. The vapor pressure molecular weight value of the methyl ester was 471; the  
 major mass spectral peaks ran up to 414.  
 Example 8: Effect of Excess Water on the oligomerization Fifty grams of the unneutralized acid product of Example l was placed in a Fischer-Porter bottle equipped with a magnetic stirrer along with 10 grams of water. The mixture was heated to 150C. and stirred at this temperature for 6 hours. At the end of this time cold neutralization with NaOH required 3.08 millimols/g. Deoiling as before showed that sulfonic acid has been formed and that only 10% of the original sultone remained. In this case, in contrast to Example 2, the material had not been oligomerized, but had been simply hydrolyzed to alkeneand hydroxyalkane-sulfonic acid. Both the acid and the sodium salt showed substantial 965 cm&#34; peaks in the IR spectrum. Analytical hydrogenation of the salt showed the presence of about 67% alkene-sulfonate. The presence of hydroxyl groups was demonstrated by converting the hydroxy-alkane acid component back to sultone as follows. The water was removed by vacuum from a 2.01 g. sample of the above hydrolyzed acidic product, followed by heating at C. for 1 hour. Cold neutralization of this product gave a neutralization equivalent of 2.47 millimoleslgram or a decrease of 31% compared with the hydrolyzed acid on a dry basis.  
 Example 9: Conversion of Normal Olefin Sulfonate to Methyl Ester A 19 g. sample of normal neutralized and hydrolyzed l-hexadecene sulfonate, as described in Example 1, in aqueous solution (25%) was subjected to the ether-HCl extraction procedure [Referencez R. House and J. L. Darragh. Anal. Chem. 26, 1492 (1954)] to convert it to the corresponding sulfonic acid dissolved in ether. The ether solution was methylated as in Example 3 to form 17.25 g. of clear, yellow oil whose IR spectrum showed substantial hydroxyl adsorption at 3,2003,600 Cm, and large bands at 1,350, 1,170 and 995 cm&#34;.  
 Example 10: Plasticization of Polyvinyl Chloride The methyl esters of Examples 3 and 9 were mixed in a 60/40/1 ratio with a commerical polyvinyl chloride resin/ester/commerical stabilizer and pressed into sheets at 182C. Both materials plasticized the resin. Physical properties of the plastic sheets were as follows:  
 VOLATlLITY. A at COMPATlBlLlTY 200F. 66 HRS.  
 Example 3, Oligomer Ester Fair 6.3 C ommereial Dioetyl Phthalate Standard 10.5 Example 9, Olefin Sulfonate Poor 16.3  
 Ester These data indicate that the SO -olefin sulfonate oligomer products are useful plasticizers for polyvinyl chloride resins.  
 Example 11: Preparation of Mixed Olefin-S0 Reaction Mixture The reactor used for this sulfonation consisted of a continuous falling film-type unit in the form of a vertical water-jacketed tube. Both the olefin and the SO -air mixture were introduced at the top of the reactor and flowed concurrently down the reactor. At the bottom the sulfonated product was separated from the air stream.  
  The olefin feed was a straight-chain l-olefin blend produced by cracking highly paraffmic wax and having the following composition by weight: 1% tetradecene. 27% pentadecene, 29% hexadecene, 28% heptadecene, 14% octadecene and 1% nonadecene. This mixture was charged to the top of the above described reactor at a rate of 306 pounds/hour. At the same time 124.2 pounds/hour of S diluted with air to 3% by volume concentration of 80;, was introduced into the top of the reactor. The reactor was cooled with water to maintain the temperature of the effluent product within water and isopropyl alcohol. One-half gram of the re sulting test solution was dissolved in 100 ml of water in a 600 ml graduated beaker. The solution was stirred rapidly for 1 minute with an efficient stirrer. This procedure converted essentially all of the liquid into foam. The maximum volume of foam and the time required for 50 ml of liquid to drain from the foam were measured (Run No. l). The same experiment was also carried out on a mixture consisting of 24 parts of the neutralized product of Example 12 and 16 parts ofthe neutralized monosulfonate prepared in Example 11 (Run No. 2) dissolved in 60 parts of the water isopropanol solvent. Two other experiments (Runs 3 and 4) were carried out using 1 gram portions of the two test soluthe range of 4346C. The average residence time of tions dissolved in 100 ml of water. The same four exthe reactants in the reactor was less than 2 minutes. After passing out of the sulfonation reactor the sulfo- TEST SOLUTION periments were then carried out with 10 ml of added kerosene. The results are given in the following table:  
 WITHOUT KEROSENE WITH KEROSENE Time Time Initial for 50% Initial for 50% Gms/ 100 Ml Foam Drain Foam Drain Run No. Water Composition (Ml) Min.) (Ml) (Min.)  
 1 0.5 Oligomer 400 3-1/6 375 3-1/3 Sulfonate 2 0.5 Oligomer 400 3-5/6 400 4S/6 Sulfonate/ Monosulfonate 3 1.0 Oligomer 450 3-1/3 450 4-1/3 Sulfonate 4 1.0 Oligomer 475 4-1/6 500 5-1/3 Sulfonatc/ nated product was mixed with 612 pounds/hour or 11.2% aqueous caustic and heated to l45-l50C. in a tubular reactor at an average residence time of minutes in order to hydrolyze and neutralize the sulfonated product. Olefin sulfonates were produced at the rate of 463 pounds per hour as an aqueous solution having a by weight solids content and a pH of 10.8  
  A portion of this product was analyzed and shown to be made up of the sodium salts of alkene sulfonic acids, hydroxyalkane sulfonic acids, and disulfonic acids. These three major components were present in a weight ratio of about /35/15, respectively.  
  After operating in the above-described manner for several hours, the neutralization and hydrolysis vessels were replaced by a collecting tank, and the acid reaction product was collected for use as a feed for the oligomerization reaction.  
 Example 12: oligomerization of n-C C Mixed Olefin-S0 Sulfonate The acid product from Example 11 was heated at Example 13: Foam Stability of the Oligomeric Sulfonic Acid Salts and Mixtures Thereof The neutralized reaction product from Example 12. 43 parts, was dissolved in 57 parts of a 2/1 mixture of Monosulfonatc These data demonstrate that olefin sulfonate oligomers are excellent foaming agents. being particularly suitable for use in the preparation of foamed oil well circulation fluids. The oligomer-monomer sulfonate mixtures moreover, yield even better foamed well circulation fluids.  
 Example 14: Effect of Water on oligomerization Reaction Stainless steel tubes having a capacity of 15 ml were charged with 10 grams of a test solution made up of the olefin/S0 reaction mixture from Example 1 l and water. The tubes were sealed and inserted horizontally into a large metal block maintained at a temperature of 150C. The entire block with the enclosed tubes was shaken at a rate of 150 cycles per minute, for 2 hours. Then the tubes were quenched by immersion into cold water.  
  The contents of each tube were removed and checked for appearance and viscosity. A weighted portion of each test mixture, about 0.4-0.45 grams. was dissolved in 50 m1 of ethanol and neutralized with 0.1 n NaOH. The resulting solution was then diluted to ml with water and examined for solubility. The increasing presence of unconverted, neutral, water insoluble alkane sultone was observed at the water content present during oligomerization increased:  
 TEST SOLUTlON REACTION PRODUCT -Continued TEST SOLL&#39;TlON REACTION PRODL&#39;CT Example Effect of Temperature on Oligomerization Reaction A 500 ml 3-inch round bottom flask, equipped with a paddle stirrer, a nitrogen inlet, thermometer and gas outlet tube was heated to about 5-l0C. above the desired temperature. Nitrogen gas was passed slowly through the flask. Then an olefin/S0 reaction mixture made as in Example 1 l and weighing about 200 grams, was charged to the flask. The reaction mixture was stirred with nitrogen flowing over the surface. Samples were removed periodically and cooled to room temperature.  
  Each sample was checked for color and viscosity. and an 0.4 to 0.5 gram sample was titrated with 0.1 NaOH to determine the acid content. Another small portion was titrated for anionic surface active components with a standard cationic surfactant.  
  The extent of reaction at various times was determined for runs at four temperatures:  
  Time to Time to 7571 Temp. C. Conversion (Hrs) Conversion (Hrs.)  
  These data demonstrate that temperature effects in the oligomerization herein are the usual timetemperature relationship. i.e., roughly a doubling of reaction rate occurs for each 100C. increase in reaction temperature.  
 Examples l622:  
 A series of sultones were prepared and oligomerized Examples 23-27: Oligomers as Built Detergents The surface active nature of the present oligomers. particularly the C Cm-disulfonates. i.e., oligomers of the C -C sultones. in built detergent formulations was demonstrated as follows. Representative oligomers obtained in Examples 6 and l6-22 were each neutralized with aqueous caustic and then evaporated to dryness to give the corresponding solid sodium salts. These salts were each compounded into a detergent formulation having the following composition in parts by weight: 25 parts of the sodium salt of the polysulfonic acid, 7 parts sodium silicate. 1 part carboxy methyl cellulose, 8 parts water, and 59 parts sodium sulfate. The resulting compositions were each dissolved in 50 ppm hard water to give an 0.1% concentration which was then tested for detergency. In this detergency test, the soil removal efficiency of a test material is related to that of a good and a bad standard. The good standard is arbitrarily assigned a detergency rating of 6 and the poor standard a rating of 2. Then the test materials are given values on the same scale according to their relative&#39;detergencies compared to the standards. The results of this detergency test are given in the following table:  
  These data demonstrate that the subject sulfonate oligomers and particular those of the C to about the C sultones, hydroxyalkane sulfonic acids and the alkene sulfonic acids or mixtures thereof are useful built detergents. Individual molecular weight i.e., C-number species and mixtures or fractions of the C .,C oligomers are also useful. Other builders such as sulfate salts. phosphate builders and phosphate-free builders. as known in the art, are also suitable for the compounding of built detergents with the present novel oligomeric sulfonc acid salts (i.e.. the usual water soluble alkaline salts such as the alkali metal salts, e.g., sodium and potassium; the ammonium salts the calcium and magnesium salts and the like, as known in the detergent art). The unneutralized oligomers herein, i.e., the disulfonic acids per se are useful as the foaming agent for the production of performed acidic well circulation fluids, particularly in the oil well servicing art.  
 Examples 28-34 In the use of foaming agents for the preparation of foamed well circulation fluids liquid concentrates of the surface active agent are ordinarily employed provided that phase separations, particularly solid formations. do not occur upon standing or at the low temperatures often encountered at the wellhead in the field. These examples demonstrate that liquid concentrates of mixtures of the subject oligomers with the precursor monomer or of the oligomers per se are useful foaming agents having excellent low temperature characteristics. The olefin sulfonate monomer used in these examples was the C C ,,-product obtained by base hydrolysis of the product described in Example 1 l. The oligomer used was the product obtained as described in Example 12. The liquid concentrates tested contained 40 parts (weight) water. 20 parts isopropanol and 40 parts of the active. as noted in the table below. These concentrates were cooled to 0C. with the results as also noted in the table below:  
 Example Oligomer-Monomer No. Weight Ratio Observation 28 0/100 Rapid solidification 29 /80 Rapid solidification 30 30/70 Slow solidification 3i /60 Slow solidification 32 /50 Mostly Liquid. Some Suspended Solids 33 /40 Clear Solution 34 l00/0 C lcar Solution When other lower alcohols (i.e., alcohols having less than 4 carbon atoms) such as methanol, ethanol. npropanol and mixtures thereof are used. as the 00501- vent similar results are obtainable.  
  The foregoing examples demonstrate that the subject disulfonate oligomers per se yield liquid detergent concentrates having excellent low temperature characteristics, e.g.. solubility etc. Similarly these data demonstrate that the subject oligomeric disulfonates are useful as additives for the improvement of the low temperature characteristics of sulfonate detergent actives whose liquid concentrates have poor low temperature solubilities.  
 We claim:  
  1. Polyvinyl chloride composition comprising polyvinyl chloride resin and a plasticizing amount of methyl ester of oligomeric sulfonic acid composition obtained 16 by heating in the liquid phase a feed comprising at least one straight chain compound having a carbon atom content in the range from 5 to 30 selected from the group of formula b. RCH(OH)(CHz),CHRSO H, and  
 c. RCH=CH(CH ),.CHRSO H wherein is a number in the range 0 3 and y is a number in the range 0 n, wherein n is a number which is 4 less than the number of carbon atoms in the longest straight chain of the compound containing the -SO H group as a substituent, and wherein the several R groups are the same or different and are hydrogen or alkyl hydrocarbon radicals; said heating being at a temperature above about 1 10C and below the carbonization temperature of the feed, in the substantial absence of water, and for a period at least sufficient for a significant conversion of the feed to the corresponding oligomeric disulfonic acids.  
 2. The composition of claim 1 in which the straight chain compound contains 16 carbon atoms.