Abstract: The cationic surfactant 1,3-dibenzyl-2-undecyl benzimidazole quaternary ammonium salt(UBS) was prepared by the reaction of benzyl chloride with 2-undecyl benzimidazole(UB), which was synthesized with o-phenylenediamine and lauric acid. The structures of UB and UBS were characterized by IR and 1H-NMR. The surface activities of UBS in aqueous solution were studied at different temperature. At 35 ℃, the critical micelle concentration (CMC) of UBS is 0.51 mmol/L and the surface tension at CMC (γCMC) is 39.6 mN/m. As the temperature decreases, the CMC of UBS lessens slightly and the γCMC increases. The foam properties of UBS aqueous solution were determined and compared with LAS and OP-10, the foaming power of UBS is the highest and its steady of foam is the lowest among of them. 

Key words: Benzimidazole, Quaternary ammonium salt, Surfactant

摘要： 以邻苯二胺和月桂酸为原料，合成了中间体2-十一烷基苯并咪唑，进一步与苄基氯反应合成了阳离子表面活性剂1,3-二苄基-2-十一烷基苯并咪唑季铵盐(UBS)。通过IR和 1H-NMR对中间体及目标产物进行了结构表征。研究了UBS在水溶液中的表面活性。35 ℃下，它的临界胶束浓度(CMC)为0.51 mmol/L，临界胶束浓度时的表面张力(γCMC)为39.6 mN/m；随着温度降低，其CMC略有减小，γCMC升高。比较了UBS与常见表面活性剂LAS和OP-10的泡沫性能，UBS的发泡能力强于LAS和OP-10，稳泡性较低。

关键词: 苯并咪唑 , 季铵盐 , 表面活性剂