Surface Active Properties and Soil Removal Ability of Biosurfactant

研究了羧酸型生物表面活性剂作为洗涤剂的性能，用甲醇钠中和法合成了琼胶酸（2-羟基-1，2，3-十九烷三羧酸）的单钠、双钠和三钠盐。在蒸馏水中，降低表面张力的能力最强，去污能力最强的是琼胶单钠盐。在硬水中，具有最高钙结合能力的琼脂酸三钠盐的去除能力保持在与纯水相同的水平。具有一定烷基链长的（2-烷基-3-羟基链烷酸）（碳数= 12、16、20、24和28）通过以下方案合成：（1）链烷酸乙酯的Claisen酯缩合反应;（2）NaBH_4选择性还原C=O为O-H;表面张力和水与癸烷之间的界面张力随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.