GB723330A - Improvements in and relating to the decolorisation of sulphonic acid esters - Google Patents

Abstract

Vinyl chloride polymers are plasticized by means of esters of sulphonic acids having plasticizing properties and obtained by reacting the sulpho-chlorination products of kerosene, boiling range 160 DEG to 280 DEG C., and Diesel oil, boiling range 245 DEG to 345 DEG C. with hydroxy compounds, e.g. phenol, cresylic acid or nonanol, the esters being decolorized by treating them at elevated temperatures with a dienophilic compound of specified type and then removing the reaction products together with any unreacted dienophilic compound from the purified ester by treating with aqueous caustic alkali solution (see Group IV (b)).ALSO:Esters of sulphonic acids obtained by reacting the sulpho chlorination products of kerosene, boiling range 160 DEG C. to 280 DEG C., and diesel oil, boiling range 245 DEG to 345 DEG C. with hydroxy compounds, are decolorized by treating the esters at elevated temperatures with a dienophilic compound and then removing the reaction products together with any unreacted dienophilic compound by treatment with aqueous caustic alkali solution, the dienophilic compound being an acid having the formula X1X2C = CX3X4, or an anhydride thereof, where X1 is a hydrogen atom or an alkyl group; X2 is a hydrogen atom, an alkyl group or a -CO.OH group; X3 is a -CO.OH group; and X4 is a hydrogen atom or an alkyl group when X2 is a carboxylic group or if X2 is hydrogen or alkyl, is a -CX5X6 COOH group where X5 and X6 are each either a hydrogen atom or an alkyl group. Specified dienophilic compounds are maleic anhydride, fumaric acid, citraconic anhydride and itaconic acid. The esters are generally heated with 1 to 5 per cent by weight of the dienophilic compound at 100-160 DEG C. for 2-24 hours. Removal of the reaction products and unreacted dienophilic compound may be effected with dilute aqueous caustic alkali and separating the resulting two layers or with highly concentrated alkali and filtering off the solid product, often removal of water by calcium chloride, alumina, sodium sulphate or other dehydrant. The esters may be further decolorized by charcoal treatment. Examples describe the decolorization as above of esters obtained by reacting a kerosene with sulphur dioxide and chlorine in the presence of ultra-violet light and reacting the resultant product with cresylic acid in presence of ammonia. In place of cresylic acid, phenol or nonanol may be used. The ammonia may be replaced by caustic soda. Such esters may be used as plasticizers for polyvinyl polymers.