Surface Active Properties and Soil Removal Ability of Biosurfactant

采用甲醇钠中和法制备了木耳酸单钠盐、二钠盐和三钠盐(2-羟基-1，2，3-十一烷基三羧酸)。木耳单钠降低表面张力的能力最强，在蒸馏水中去除土壤的能力最强。在硬水中，除钙能力最强的木耳酸三钠盐的脱除能力与蒸馏水中相当，同时合成了5种具有一定烷基链长(碳数分别为12、16、20、24、28)的棒状真菌酸(2-烷基-3-羟基烷酸)：(1)烷酸乙酯缩合；(2)NaBH_4选择性还原C=O为O-H；(3)碱性条件下羟基酯的水解。表面张力和水与正庚烷之间的界面张力随着碳数的增加而显著降低。

The properties of carboxylic-type biosurfactant as detergents were investigated.Mono-, di- and trisodium salts of agaricic acid (2-hydroxy-1,2,3-nonadecanetricaboxylic acid) were prepared by neutralization with sodium methoxide. Monosodium salt of agaricic had the most ability for lowering surface tension and was best capable of soil removal in distillled water. In hard water, the removal ability of trisodium salt of agaricic acid which had the highest calcium binding capacity was retained at the same level as in distillled water.Also, five kinds of Corynomycolic acids (2-alky1-3hydroxy alkanoic acid) having definite alkyl chain lengths (carbon number = 12, 16, 20, 24 and 28) were synthesiztd by the following scheme : (1) Claisen ester condensation of ethyl alkanoate, (2) selective reduction of C=O to O-H by NaBH_4 and (3) hydrolysis of hydroxyester under alkaline condition. Surface tension and the interfacial tension between water and decane decrease significantly with increasing carbon numbers.