Abstract: The content of di-sodium salt（DSS）in every step of MES’s synthesis was measured，the maximal decrease of DSS is in reesterification stage，the maximal increase of DSS is in neutralization stage. It could be resulted from the methanol introduction in reesterification stage， strong alkaline environment and higher temperature in neutralization stage. Meanwhile，improvement is also proposed for every stage in ameliorated method. By optimizing the experiment，the optimal condition for every stage was obtained as，bleaching temperature 75 ℃，reesterification time 6h，the mole ratio of methanol to fatty acid methyl ester sulfonic acid 30∶1，neutralization pattern，dry neutralization by sodium carbonate powder when the content of di-sodium salt is the lowest.

Key words: di-sodium salt, bleach, reesterification, neutralization

摘要： 实验考察了脂肪酸甲酯磺酸盐（MES）合成的各工序中α-磺基脂肪酸二钠（二钠盐）的变化量。其中再酯化阶段二钠盐减少最多，中和阶段二钠盐产生最多，这是由于再酯化阶段引入了部分甲醇以及中和阶段的强碱性环境和较高温度引起的。同时提出了各阶段的改进方法。经过优化实验，得到二钠盐含量最低时，各阶段最佳条件为：漂白温度75 ℃，再酯化时间6 h，甲醇与脂肪酸甲酯磺酸摩尔比30∶1，中和方式为以碳酸钠粉末干法中和。

关键词: 二钠盐, 漂白, 再酯化, 中和