Preparation of sodium salts of N-sulfonic acids by sulfomethylation of nitro oligomers obtained from waste rubbers

摘要

The sulfomethylation of nitro oligomers obtained from waste rubbers (NO-GWR) with sodium hydroxymethane sulfonate was studied in aqueous-alkali solutions from 50 to 80degreesC for reaction times of 3.5-5.5 h with weight ratios of 1.0:0.3-0.6. The initial NO-GWR was produced by the oxidation/ destructive nitration of waste rubbers with nitric acid in a heterogeneous medium. The influence of the reaction conditions on the yields and functional compositions of the sodium salts of two types of N-sulfonic acids was investigated. Some of the nitro groups transformed into sulfaminate groups at 80degreesC or lower. One type of N-sulfonic acid was isolated from its sodium salt by ion exchange. The oligosulfo derivatives were characterized by elemental and thermal analyses, IR and H-1-NMR spectroscopy, and the number-average molecular weight. The sodium salts of the N-sulfonic acids obtained from NO-GWR possessed functional compositions similar to those of sodium salts from butadiene-styrene nitro oligomers prepared from butadiene-styrene latexes. Therefore, NO-GWR obtained from available raw materials can be used as the initial derivative for the preparation of salts of N-sulfonic acids instead of the nitro oligomers used now from elastomers. The salts can be used in galvanic coating techniques as brighteners. (C) 2005 Wiley Periodicals, Inc.