Tehrani-Bagha A R, Oskarsson H, van Ginkel C G, Holmberg K
Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
J Colloid Interface Sci. 2007 Aug 15;312(2):444-52. doi: 10.1016/j.jcis.2007.03.044. Epub 2007 Mar 27.
Two cationic gemini surfactants having ester bonds between the hydrophobic tail and the cationic moiety have been synthesized. The ester bonds were either with the ester carbonyl group away from the positive charge (esterquat type arrangement) or facing the positive charge (betaine ester type arrangement). The chemical hydrolysis of the surfactants was investigated and compared with the hydrolysis of the corresponding monomeric surfactants. The betaine ester type of surfactants was found to hydrolyze much faster than the esterquat surfactants. It was also seen that above the critical micelle concentration the gemini surfactants were much more susceptible to alkaline hydrolysis than the corresponding monomeric surfactants. The biodegradation of the geminis and the monomeric surfactants were also studied. It was found that whereas the monomeric surfactants were rapidly degraded, the two gemini surfactants were more resistant to biodegradation and could not be classified as readily biodegradable. The 60% biodegradation was reached after 35-40 days. Thus, there was no correlation between rate of chemical hydrolysis and rate of biodegradation.
已合成了两种在疏水尾部和阳离子部分之间具有酯键的阳离子双子表面活性剂。酯键要么是酯羰基远离正电荷（酯季铵盐型排列），要么是面对正电荷（甜菜碱酯型排列）。研究了这些表面活性剂的化学水解，并与相应的单体表面活性剂的水解进行了比较。发现甜菜碱酯型表面活性剂的水解速度比酯季铵盐表面活性剂快得多。还可以看出，在临界胶束浓度以上，双子表面活性剂比相应的单体表面活性剂更容易受到碱水解的影响。还研究了双子表面活性剂和单体表面活性剂的生物降解。结果发现，单体表面活性剂迅速降解，而两种双子表面活性剂对生物降解更具抗性，不能归类为易生物降解。35 - 40天后达到60%的生物降解率。因此，化学水解速率和生物降解速率之间没有相关性。
