Method for purifying alpha-sulfo fatty acid salt

The invention relates to a method for purifying a crude alpha-sulfo fatty acid salt obtained by reacting a fatty acid with a sulfur oxide, comprising the following steps: a) diluting the crude alpha-sulfo fatty acid in a solvent and adjusting the pH to 2 to 4; b) heating the slurry of the alpha-sulfo fatty acid salt obtained in step a) until complete dissolution; c) gradually cooling the alpha-sulfo fatty acid salt solution obtained in the step b) to room temperature to obtain crystals; and d) filtering the crystals obtained in step c) to remove the mother liquor, and flushing the filter cake with an acidic aqueous solution at least twice to obtain the purified alpha-sulfo fatty acid salt. 本发明涉及一种用于纯化由脂肪酸与硫氧化物反应获得的粗α-磺基脂肪酸盐的方法，其包括以下步骤：a)将粗α-磺基脂肪酸在溶剂中稀释并将pH调节到2至4；b)加热步骤a)中获得的α-磺基脂肪酸盐的浆料直至完全溶解；c)将步骤b)中获得的α-磺基脂肪酸盐溶液逐渐冷却至室温，以获得晶体；d)将步骤c)中获得的晶体过滤以除去母液，并用酸性水溶液冲洗滤饼至少两次，以获得纯化的α-磺基脂肪酸盐。