脂肪酸甲酯磺酸钠盐的纯化

Purification of Sulfonated Fatty Acid Methyl Ester

二步溶剂结晶法纯化了脂肪酸甲酯磺酸钠盐表面活性剂。将每10 gα-磺酸脂肪酸甲酯工业品用NaOH的无水乙醇溶液中和至pH=7.0,再加入无水乙醇定容至80 mL,60℃过滤,得到的滤液加无水乙醇定容至80 mL,在10℃结晶2 h,所得晶体中α-磺酸脂肪酸甲酯钠盐、α-磺酸脂肪酸二钠盐和脂肪酸钠皂的质量分数分别由74.38%、16.30%和8.83%改善为94.74%、1.12%和4.01%。同时,黑色的脂肪酸甲酯磺酸钠盐工业品纯化为浅黄色的晶体,收率为48.03%。纯化前后脂肪酸甲酯磺酸钠盐在30℃时的临界胶束浓度由6.47×10-3mol/L降低到6.68×10-4mol/L,c20由2.14×10-4mol/L降低到9.48×10-5mol/L。

Sulfonated fatty acid methyl ester surfactant is purified by two-step solvent crystallization. Dissolve 10 g of this surfactant in 80 mL ethanol ,filter at 60 ℃ ,and crystallize at 10 ℃ for 2 h. In this way, the black crude surfactant becomes light yellow crystals, composed of 94. 74% of α-sulfo-fatty acid methyl ester sodium salt, 1.12% of α-sulfo-fatty acid disodium salt and 4. 01% of fatty acid sodium salt （soap）. By contrast, in the original sulfonated fatty acid methyl ester, contents of these ingredients are respectively 74. 38% , 16. 30% and 8. 83%. The yield of two-step solvent crystallization is 48.03% of the raw material. Before and after purification, the critical micelle concentration and c20 of the sulfonated fatty acid methyl ester surfactant at 30 ℃ decreases from 6. 47 ×10^-3 mol/L and 2. 14 ×10^-4 mol/L to 6. 68 ×10^-4 mol/L and 9.48×10^-5 mol/L respectively.