DE1039229B - Process for the preparation of straight chain sulfonates of high molecular weight alkenyl aromatic resins - Google Patents

Description

Process for the preparation of straight-chain sulfonates of aromatic High Molecular Weight Alkenyl Resins The invention relates to a process for Manufacture of certain, essentially straight-chain, water-soluble resin polysulfonates very high molecular weight, derived from alkenyl aromatic polymers derive.

The alkenyl aromatic resins with which the invention is concerned in particular are toluene-soluble, thermoplastic polymers and copolymers of alkenyl aromatic compounds of the benzene series with the structural formula: in which the designation R1 is hydrogen, chlorine or a lower alkyl group such as methyl or ethyl, the designation R2 is hydrogen or a lower alkyl group such as methyl or ethyl and the designation R3 is hydrogen or the methyl group and the other designations are their usual ones Have meaning. Examples of such alkenyl aromatic resins are the solid homopolymers of styrene. x-methylstyrene, ar-vinyltoluene, ar-vinyxylene, a, ar-dimethylstyrene, ar-ethylstyrene and ar-chlorostyrene. This also includes the solid copolymers of two or more of these alkenyl aromatic compounds in any ratio to one another and the solid copolymers of one or more such alkenyl aromatic compounds and a small amount of one or more mixed polymerizable monovinylidene compounds, in particular polymers of 85 to 100 percent by weight of at least one such allzenvlaromatic Compound and correspondingly 0 to 15 percent by weight of acrylonitrile. Particular examples of usable copolymers are those of styrene and ar-vinyltoluene in equimolecular proportions, copolymers of at least 85 percent by weight of ar-vinyltoluene and not more than 15 percent by weight of acrylonitrile and copolymers of at least 85 percent by weight of styrene and not more than 15 percent by weight of acrylonitrile.

Toluene-soluble, solid, thermoplastic alkenyl aromatic resins with high molecular weight of the type mentioned, which are used to produce the special polysulfonates are suitable according to the invention are those whose solution viscosities are at least 100 cP and preferably greater than 500 cP. The term "solution viscosity", as it is used in the present documents, means the viscosity at 25 ° C of a 10 percent strength by weight solution of the polymeric resin in toluene, as it is with a modified Ostwald viscometer (1949, ASTM Standards, Part 6, p. 478 to 479) is determined. It should be mentioned that the usual molding qualities of the polystyrene Have solution viscosities between 20 and 40 cP and for the present purpose are unsuitable. On the other hand, high solution viscosity resins are like that Invention requires, unsuitable for general use as molding resins.

The toluene-soluble, solid, thermoplastic alkeny-1-aromatic resins of high molecular weight of the type described can be sulfonated to resin polysulfonates by introducing a number of sulfonic acid groups into the resin molecules. The resin polysulfonates to which the invention relates are such. which are soluble in water and have Brookfield viscosity values of at least 35 cP. The term "Brookfield viscosity" as used here means the viscosity of a neutral (pA = 7) aqueous solution of the sodium salt of the resin sulfonate at 25 ° C., as determined with the Brookfield viscometer. if you use spindles No. 1 or No. 2 rotating at six revolutions per minute (Leaman, "Rubber Age", vol. 69 pp. 702 to 703). For this purpose, a weighed sample of the free acid of the resin sulfonate is dissolved in water, the acidic solution up to a p11 value of 7 by adding a 1 na äs-erige = LQsytxg vb @ ii: cintlti Sodium hydroxide neutralized and hurried on. A't rg i = valent content of 0.5 percent by weight of Siütfe des Resin sulfonate diluted. Insl @ äsorirt, snd; .the water-soluble..Iärzpcyly # suV fönate riach - der E'rfiirdunw'-mit'-seirrho'lreri-tv @ ölekifl- = blows such; Ä, eren Brookfield viscosity values are related to the Solventing viscosity values of the starting polymers as it .das. Can recognize the curve of the drawing. The sulfonates according to the invention are shown in the drawing as area I, which lies between the lines AB and CD. The gradations of the graph are three-fold logarithmic scales, the abscissa indicating the solution viscosity of the starting resin, while the ordinate denotes the Brookfield viscosity of the corresponding resin sulfonate.

The new resin sulfonates of this particular type have unusual ones and unexpected properties that make them particularly useful as a means of improving agricultural Make soils and / or colloidal brine suitable as a means for flocculating.

According to the invention there are new and advantageous resin sulfonates which can be used obtained, in particular water-soluble polysulfonates from essentially straight-chain, toluene-soluble, thermoplastic, solid, alkenyl aromatic resins very high molecular weight.

Such resins are particularly useful for improving the structure and the Suitable for ordering agricultural soils.

Furthermore, these resins are excellent for making sols of colloidal To flocculate solid substances that are dispersed in aqueous media. Further The objectives and advantages of the invention are evident from the description below.

The objects of the invention are achieved by means of the water-soluble ones already described Sulfonates. These sulfonates are obtained by using a toluene-soluble, thermoplastic, solid, alkenyl aromatic resin of very high molecular weight of the type described Subjects type of sulfonation and introduces sulfonic acid groups into the resin molecules, at the same time there was a noticeable introduction or formation of other types of groups or residues in the resin molecules, especially cross-linking groups, avoided will. The sulfonation process must be specially managed in order to achieve a noticeable Formation of cross links, e.g. B. sulfone cross-links between the polymer molecules to avoid, since such a formation of cross-bonds the sulfonation product insoluble in water and unsuitable for the present purposes.

In one embodiment of the preparation of the sulfonates according to the invention, a solid polymerizate or copolymer of an alkenyl aromatic resin of the type mentioned above is dissolved in a mixture which consists essentially of 20 to 80 percent by weight of liquid sulfur dioxide and the rest of at least one chlorinated aliphatic hydrocarbon, such as methylene chloride, Ethylene chloride. Carbon tetrachloride,: flethylc'hloroform or tetrachlorethylene. The resulting solution can be five or less percent by weight. preferably 0.5 to 2 percent by weight of the polymeric resin to be sulfonated. The solution is stirred and kept at temperatures between -20 and + 40 ° C. a solution containing 5 or less percent by weight of freshly prepared sulfur trioxide in a separate amount of said mixed -Isur @ snütt @ ls # @ or in one of the components of the mixed solvent, added with stirring is set. D .. -r addition will be made as soon as possible, for example within 1 to 20 minutes, where das': IZ4a @ ffonsggemiscli kept under a pressure -rovird, which is sufficient to keep at least a larger part of the solvent mixture in the liquid state. A sufficient amount of sulfur trioxide must be used in order to produce a proportion which corresponds to the ratio theoretically required for the introduction of 0.7 to 1.1 sulfonic acid residues onto the aromatic nucleus of the polymer to be sulfonated. After the sulfonation reaction has ended, the sulfonate precipitates from the reaction medium and can be separated off and using customary procedures, such as filtration. Washed out with fresh amounts of the solvent mixture and / or with other liquid extractants and drying can be recovered.

The water-soluble sulfortates of the invention are solid, generally colorless products. They are soluble in water to form viscous, colorless acidic solutions.

The free acids of the resin sulfonates can by reaction with bases, such as alkali bases, alkaline earth bases, ammonia or aniine bosoms; to be converted to salts. For example, the free acid form of the resin sulfonates can be mixed with Amnioni; ak, sodium hydroxide. Sodium carbonate, sodium, mbicarhonat, potassium hydroxide, lithium hydroxide or calcium hydroxide are converted to the corresponding salt forms of the resin sulfonates. Here is the term "sulfonate" is understood to mean the free sulfonic acid forms of the sulfonated alkene laromatic resin products and their alkali sulfonate salts.

The following examples serve to illustrate the invention, but should not limit their scope of protection.

Example 1 A series of copolymers from equimolecular proportions from styrene and ar-vinyltoluene (a mixture of approximately 60 percent by weight of m-vinyltoluene and approximately 40 weight percent p-vinyltoluene) was obtained to give a series of Resin polysulfonates sulfonated. In Table I below, for each of eight sulfonation products with the numbers 1 to 8 the solution viscosity of the starting polymer resin and the Brookfield viscosity of the corresponding sulfonation product. These sulfonates were prepared using the following procedures.

Sulphonate 1: A mixture of 300 cc carbon tetrachloride and 300 ccm of liquid sulfur dioxide was placed in a reaction vessel at a temperature of -10 ° C brought in. Thereafter, the reaction vessel became a solution of 4.15 cc of liquid Sulfur trioxide in 250 cc of liquid sulfur dioxide and at the same time a solution of 10g of the copolymer (solution viscosity 10 cP) in a mixture of 125 ccm of liquid sulfur dioxide and 125 ccni of carbon tetrachloride added, whereby both solutions had a temperature of -10 ° C and the time of addition 10 Minutes. The reaction mixture was kept at approximately -10 ° C and passed through Stirring set in motion. The liquid reaction medium became the solid sulfonation product isolated and dried. A sample of this product was extracted with ether and dried. 1 g of the resin sulfonate purified with ether, solved in water, required 4.0 ccm of 1N Na O 1tI ° "solution for neutralization: -Its BrookfieiüViscosity: req 7 cl '. - -Sulfonate 2: The process steps described for the production of sulfonate 1 would-.tnter-_ use of a starting copolymer with a solution viscosity of 100 cP repeated. 1 g of the resin sulfonate purified with ether, dissolved in water, 4.0 ccm l n-Na O H solution for neutralization. The Brookfield Viscosity was 35 cP.

Sulphonate 3: A reaction vessel was given a solution of 504.4 g of copolymer (solution viscosity 100 cP) in a mixture of 28.5k carbon tetrachloride and 25.5 kg of liquid sulfur dioxide at an average rate of 88 ccm per minute simultaneously with an inflow of a liquid solution of 420 g of sulfur trioxide in 42.1 kg of liquid sulfur dioxide is fed at an average rate of 112 cc per minute. A stream of the reaction mixture was continuously withdrawn from the reaction vessel, the latter being kept at approximately -10 ° C. with vigorous stirring. The solid sulfonation product was isolated from the liquid reaction medium and dried. A sample of the same was extracted with ether and dried, 1 g of the resin sulfonic acid purified with ether, dissolved in water, requiring 4.4 ccm of 1N NaOH solution for neutralization. Its Brookfield viscosity was 100 cps.

Sulphonate 4: A 54 cc portion of a solution that is 10 percent by weight Sulfur trioxide contained in liquid Sch @ vefeldioxvd at -10 ° C, was with further 346 ccm of liquid sulfur dioxide diluted at -10 ° C. The solution obtained was at the same time with a solution of 10 g of mixed polymer (solution viscosity 694 cP) in 400 cc carbon tetrachloride in a reaction vessel, initially a mixture from 250 ccm carbon tetrachloride and 250 ccm liquid sulfur dioxide at -10 ° C contained, added. Mixing was done with vigorous stirring. The addition of the Reaction participants required 9 1minutes, with the reaction mixture on approximately -10 ° C was kept. Resin sulfonic acid was obtained in the usual manner. 1 g the resin sulfonic acid purified with ether, dissolved in water, required 4.8 cc 1 n-Na O H for neutralization. Its Brookfield viscosity was 130 cps.

Sulfonate 5: The procedure described for the preparation of sulfonate 4 was essentially repeated with the exception that the added copolymer solution 10 g copolymer in a mixture of 200 ccm carbon tetrachloride and 200 ccm of liquid sulfur dioxide dissolved, while the other starting materials and conditions were the same as those for the preparation of the sulfonate 4 are described. 1 g of the ether-purified sulfonate 5 required in water dissolved, 4.4 ccm 1 n-NaOH solution for neutralization, its Brookfield viscosity value was 184.

Sulphonates 6 and 7: The procedure used to produce, des Sulfonate 5 was essentially repeated using the same starting materials with your difference that cause some difficulties while maintaining steady flow rates of the reacting Solutions resulted. Because of this, the Brookfield viscosities were sulfonated Resin products higher (320 and 540 cP for sulfonates 6 and 7, respectively) than for the sulfonate 5. In each case 1 g of the ether-purified sulfo required 6 and 1% , dissolved in water. 4.8 ccm 1 n-Na OH-T solution for- -neutralization. - -. Sulfonate 8: Es: wttr & irr == essential those described for the preparation of the sulfonate 3 Procedure repeated, with the additional solutions ä) `a solution of 0.453 kg Copolymer (solution viscosity 694cP) in approximately 51.1 kg of carbon tetrahalocarbon with an average cutting speed of 56 cc per minute and 'b) a solution of 1 percent by weight of sulfur trioxide in liquid sulfur dioxide at an average rate of 47 cc per minute were added to a reaction vessel which was initially a liquid mixture of 300 cc carbon tetrachloride and 300 cc liquid sulfur dioxide contained. 1 g of the sulfonic acid purified with ether, dissolved in water, 4.8 ccm of 1N NaOH solution for neutralization, its Bi-Okfield viscosity value was 940 cP.

The sulfonated resins just described; as sulfonates No. 1 bis 8 have been designated as a means of improving the quality of agricultural land Floors tested. During these tests, Miami mud loam was found to be the cause of its strong density and solid putty is known in the field, made air dry and sifted through a 10 @ mesh sieve. Separate solutions were made by dissolving 0.15 g portions of each of Su-Ifonate Nos. 1 to 8 in 30 = cc portions @ n Water. The obtained solutions were each separately with stirring 300 g portions of the dry, sieved soil mixed to make soil preparations obtained, each of which contained 0.05 percent by weight of one of the sulfonates mentioned.

Each treated soil sample was placed in a standard soil pipe with a internal diameter of 47.6 mm inserted and slightly compressed to form a To obtain a floor column with a depth of 152 mm. The so produced. Pillars were up wetted with water to saturation and left to stand for 72 hours. After that it was over maintain a constant layer of water in the soil columns for 24 hours and the The speed of percolation of the water is determined by the soil column. As a control attempt an untreated amount of the sifted Miami soil was wetted with water, put in a bottom pipe and subjected to the same percolation as described. The rates of percolation of the water in cc / hour through these different Soil samples, designated by reference to the sulfonate contained therein shown in Table I.

After carrying out the percolation determination described, the soil samples were allowed to drain for 16 hours and removed from the pipes. A 200 g portion each of the wet soil samples was separated on a standard 14-mesh sieve (Tyler sieve series), which was placed over a 32-mesh screen, applied. The sieve composition was then shaken in a vessel of water for about 2 minutes until the entire fine, not Adhering soil was sifted out. Following this procedure, they became water-resistant Aggregates with diameters of 0.5 mm or more retained on the sieves. These stable aggregates were allowed to drain for 5 minutes and weighed. The amount of these persistent aggregates is in percent by weight of the moist soil as well in Table I for the various soil samples identified by reference to the sulfonate they contain.

The evaluation of these data shows that the sulfonates 17r.2 to 8 inclusive are excellent Table 1e I. Sulfonate Brookfield Viscosity Solution Viscosity Percolation Resistant Aggregates speed Num m er cp cP ccm / hr. Weight percent 1 7 10 34 16 2 35 100 153 - 3 100 100 114 34 4 130 694 537 42 5 184 694 1356 49.5 6 320 694 1115 42 7 540 694 591 40.5 8 940 694 77 35 Untreated control floor 16 13 Had an effect on the soil, as shown by the magnitude of the percolation rate and the proportion of stable aggregates in relation to the tests on the untreated control soil. Sulfonate No. 1 had negligible effect on soil and is outside the scope of the invention.

Example 2 10 g of polymerized ar-vinyltoluene (a polymer of a mixture of approximately 60 percent by weight of m-vinyltoluene and 40 percent by weight of p-vinyltoluene), characterized by a solution viscosity of 547 cP, was dissolved in 400 cc of dry carbon tetrachloride. In another vessel, 4 cc of sulfur trioxide were dissolved in 400 cc of liquid sulfur dioxide at -10 ° C. These two solutions were added simultaneously and at the same rate with stirring to a reaction vessel which contained a solution of 250 cc of carbon tetrachloride and 250 cc of liquid sulfur dioxide at a temperature of -10 ° C. The addition of the two solutions was carried out over a period of 12 minutes, with continued stirring and the reaction vessel and contents being kept at a temperature of -10 ° C. The reaction product precipitated as a white powder was separated off by filtration. The crude product was then purified by washing with dry dietary ether and the purified product was dried in a vacuum oven at 10 torr and at a temperature of 100 ° C. One gram of the pure rosin sulfonic acid, dissolved in water, required 4.4 cctn of 1N NaOH solution for neutralization. Its Brookfield viscosity value was 69 cps.

Example 3 10 g of polymerized ar-vinyltoluene (polymer of a Mixture of approximately 60 percent by weight m-vinyltoluene and approximately 40 percent by weight p-Vinyltoluene), characterized by a solution viscosity of 921 aP, were after a procedure which corresponded to that described in Example 2, sulfonated. 1 g of the resin sulfonic acid purified with ether, dissolved in water, required 4.4 ccm 1 n-Na O H for neutralization. Its Brookfield viscosity value was 140 cP.

Another test to demonstrate the usefulness and excellent properties of the present resin sulfonation products was carried out as follows. 45 cc of distilled water containing 0.075 g of one of the polymeric sulfonates indicated below was added to 150 Miami mud loam which had been crushed so that it passed through a sieve with openings 0.25 mm wide. The soil was mixed well and forced through a sieve with 4 mm openings. These process steps resulted in the incorporation of the polymeric sulfonate into the soil in an amount of 0.05 percent by weight. After at least three days of air drying in a warm room, 50 g samples were placed on the top sieve of a set of five sieves of 4-. 2-, 2-, 0.5- and 0.25-mm openings are given in decreasing size. The sieve set with the soil sample thereon was immersed in a quantity of water and raised and lowered repeatedly for 30 minutes while being immersed in the water, within a distance of 38 mm and at a rate of 30 changes per ½ minute. At the end of this time, the sieves were removed from the water and allowed to drain. The soil left on the sieves was dried at 100 ° C. and weighed. The same determinations were carried out with Miami mud loam without the addition of sulfonated polymer in order to serve as an untreated control sample. The results obtained from testing with several sulfonated resin products are in Table II Brookfield's solution viscosity. Water-resistant viscosity Sulphonated test resin Base polymer of the polymer sulphonate Soil aggregates 0.25 mm cP CP weight percent a) Example 1, sulfonate no. 4 from equimolecular large copolymer of styrene and ar- N "inyltoluene .............................. 694 130 83 b) Example 2, from polymeric ar-vinyltoluene ... 547 69 84 c) Example 3, from polymeric ar-vinyltoluene ... 921 140 97 Untreated control sample. .... .. .. .. ... - - 2 d) Water-soluble sulphonate from compressible Polystyrene ......... ...................... 36 3900 7 e) Water-soluble sulphonate from compressible Polystyrene ... .. .......................... 36 13000 5 Table II given. In Table II, the proportion of water-resistant soil aggregates of more than 0.25 mm in size is given in percent by weight, based on the dry content of the soil samples which contained the corresponding polymeric sulfonates. The polymeric sulfonates are indicated by the type of starting polymer, as well as their solution viscosity and the Brookfield viscosity of the polymeric sulfonate.

The tests given in Table II under d) and e) have been included for comparison purposes. The sulfonates given in these tests d) and e) are outside the scope of the invention. A number of resin sulfonates were tested as described in Example 1 for their effect on Miami muddy clay floors. The resin sulfonates and the results of these tests are shown in Table III. In Table III, the solution viscosities, as described above, relate to the polymeric base or starting resin and the Brookfield viscosities relate to the corresponding sulfonation products. The percolation rate in ccm / hour. and the proportion of permanent soil aggregates in percent by weight of the moist soil were determined in accordance with the procedure described in Example 1. Table III Solution Brookfield Percolation Resistant Test sulfonated resin) viscosity viscosity speed aggregates cp cP ccm / hour Weight percent A control experiment, untreated Floor - - 228 21 A-1 95 VT-5 VCN 779 359 1210 53 A-2 95 VT-5 VCN 779 600 1013 51 A-3 95 VT-5 VCN 779 785 946 38.5 A-4 90 VT-10 VCN 5660 1170 920 53.5 B control experiment, untreated Floor - - 65 15 B-1 96VT-4VCN 526.6 245 686 46 C control experiment, untreated Floor - - 62 19 C-1 95 VT-5 VCN 562.7 480 495 45.5 C-2 95 VT-5 VCN 562.7 1130 322 40.5 C-3 95 VT-5 VCN 562.7 3800 263 32.5 C-4 100VT 1564 1400 258 44.5 D control experiment, untreated Floor - - 31 19 D-1 100S 100 450 101 32 *) The base or the starting resin poly corresponding monomers are given at S = styrene, VCN - acrylic acid merisate. In the case of the copolymers, the numbers show the genitrile, VT - ar-vinyltoluene, a mixture of 60 percent by weight parts by weight of the m-vinyltoluene chemically bound in the copolymers and 40 percent by weight of p-vinyltoluene. Example 4 A copolymer of equimolecular proportions of styrene and ar-vinyltoluene (mixture of approximately 60 percent by weight of m-vinyltoluene and approximately 40 percent by weight of p-vinyltoluene) with a solution viscosity of 694 cP was mixed with sulfur trioxide in a liquid medium composed of sulfur dioxide and a chlorinated hydrocarbon sulfonated as described above to give a water-soluble sulfonate. The latter was separated from the reaction medium by filtration and washed with dry diethyl ether to obtain a purified product in the form of a finely divided powder. The Brookfield viscosity of the sulfonate was 176 cP.

Equal amounts by weight of this sulfonated resin and a commercially available one 4-8-4 fertilizers were mechanically mixed and powdered so that they passed through a 100 mesh sieve passed through. The resulting mixture was spread over an area from freshly prepared soil. which is usually used to toughen and educate 'hard crust tends to. distributed in an amount of 362 kg of the mixture per acre. A disc harrow was used to move the 1 table into the topmost Distribute 7.6 crn of the soil. A noticeable improvement in the soil structure and: the machinability arose in the subsequent growth period. As another Example of the usefulness of these sulfonates and to illustrate their excellent characteristic properties, the following tests were carried out.

A sludge from sewage from a soup canning factory contained about 1 percent by weight of finely divided components of pea soup in a colloid aqueous suspension with a pH value of approximately 11. The immediate drainage of sewage of this type in natural watercourses must be avoided. will. It is therefore desirable to treat this waste water so that the suspended matter flocculates and settles, causing the clear supernatant liquid can be separated from a more concentrated sludge.

Portions of the pulp described above were placed in 100 cc graduated cylinders and mixed with the various polymeric sulfonates. The polymeric sulfonates were added in the form of aqueous 0.05 percent by weight solutions, the addition taking place in portions with gentle mixing, which was completed by repeatedly inverting the closed cylinder. In any case, an amount of the polymeric sulfonate solution was mixed with an amount of Konservenabfallschlainmes so that 100 CCRN sludge with a content of approximately 25 parts by weight of the polymeric sulfonate to 1 million parts by weight of the t '-, e entire suspension was obtained. The cylinders were then placed in an upright position to initiate sedimentation. An untreated 100 cc portion of the original sludge was also stirred up by inversion and allowed to stand as a control. The volume of the supernatant liquid was measured after sedimentation for 1 and 2 minutes. The results are summarized in Table IV, in which the polymeric sulfonates are indicated by specifying the starting polymer or copolymers from which the sulfonate originated and the solution viscosity of the base and starting polymers or copolymers and the Brookfield viscosity of the sulfonate are given.

The tests identified in Table IV as Tests 2-4 illustrate resin sulfonates of the invention as noted above. Those in tests 5 through 7 Table IV Solution Brookfield volume of the supernatant Test base polymer *) viscosity viscosity liquid after cp cP 1 minute 2 minutes 1 untreated control experiment - - 0 10 2 100 VT 6600 472 40 65 3 95 VT-5 VCN 563 480 54 66 4 99 VT-LVCN 550 85 35 63 5 100 VT 23 14 0 10 6 96VT-4VCN 850 50,000 (gel) 0 10 7 96VT-4VCN 120 20 0 10 *) The numbers denote the parts by weight of the m-vinyltoluene and approximately 60 percent by weight in the polymer bound monomers. VT - ar-vinyltoluene, a mixture of 40 weight percent p-vinyltoluene. VCN - Acrylic Acid Nitrile. The sulfonutes used are outside the scope of the invention, from them it can be seen that no noticeable effect has occurred with regard to flocculation and sedimentation of the colloidal suspension.

The water-soluble sulfonated resins of the invention are also suitable for other known uses of water-soluble sulfonated resins, z. B. as a thickener for aqueous media, for sizing textiles, for discharging static electricity from dielectric plastics, as a leveling and pickling agents, as dispersants and emulsifiers and as protective colloids.

Claims (2)

PATENT CLAIMS: 1. Process for the production of straight-chain resin sulfonates with 'higher molecular weight by reacting sulfur trioxide with a thermoplastic polymer at least one alkene-laromatic compound, the reactants in a liquid mixture of 20 to 80 percent by weight of sulfur dioxide and 80 to 20 percent by weight of a polychlorinated hydrocarbon, preferably Methylene chloride, ethylene chloride, carbon tetrachloride, methyl chloroform or tetrachlorethylene are dissolved at a reaction temperature between -20 and -1-40o C, characterized in that the thermoplastic polymer used consists of a toluoI-soluble thermoplastic polymer composed of 85 to 100 percent by weight of at least one alkenyl aromatic compound , preferably styrene or ar-vinyltoluene, and 0 to 15 percent by weight of acrylonitrile, with the proviso that the polymer has a viscosity at 25 ° C. of m at least 100 cP and preferably at least 500 cP. 2. The method according to claim 1, characterized in that that a molecular proportion of sulfur trioxide of at least 0.7 with an amount of polymer is mixed, the 1 molar equivalent of an alkenyl aromatic Contains compound chemically bound. the proportion of liquid medium being so dimensioned is that the combined weight of sulfur trioxide and polymer, ats 5% and preferably 2% of the weight of the total mixture; does not exceed.