PRODUCTION OF HIGHLY CONCENTRATED SALT OF ALPHA-SULFOALKYL ESTER OF FATTY ACID

摘要

PROBLEM TO BE SOLVED: To minimize the by-product di-salt, obtain a high-purity highly concentrated product and realize the long-term operation by mixing anα-sulfoalkyl ester of a fatty acid with a specified amount of its neutralized reaction product beforehand and then neutralizing the mixture with aqueous alkali. SOLUTION: An alkyl ester of a fatty acid is mixed with a sulfonating agent (e.g. sulfuric anhydride) at a molar ratio of 1:(1.0 to 1.5), and the mixture is heated at 50-100 deg.C for 30-100min and then aged at 50-100 deg.C for 5-120min. Esterification is effected by mixing 100 pts.wt. sulfonated product with 1-5 pts.wt. alcohol (preferably 1-4C alcohol) under agitation at 60-90 deg.C for 10-30min. Neutralization is effected by sufficiently mixing an acid with a neutralized reaction product (recycled product) in an amount fiveto twenty-fold based on the total weight of the acid and aqueous alkali beforehand and adding a highly concentrated aqueous alkali (15-50wt.%) to the mixture. The neutralization is effected at a pH of 4 to 9 at 50-105 deg.C. This method gives an objective salt having a concentration as high as 60-80wt.%.