新型酯基咪唑类表面活性剂的合成与性能

以月桂酸、二溴新戊二醇和N-甲基咪唑为主要原料,经酯化、季铵化反应合成了一种新型双酯双咪唑类表面活性剂二溴-1,3-双(3-甲基咪唑)-2,2-双(十二酸酯甲基)-丙烷(EminC12)。实验得到酯化反应条件:n(月桂酸)∶n(二溴新戊二醇)=2.2∶1,反应温度为115℃,反应时间7 h,对甲苯磺酸为催化剂,甲苯为带水剂,得到中间体1,3-二溴-2,2-双(十二酸酯甲基)-丙烷(DEC12),产率为87%;季铵化反应条件:反应温度150℃,反应时间5 h,目标产物产率可达80%;产物结构通过元素分析、IR、1HNMR得到证实。25℃时其水溶液的临界胶束浓度为0.3 mmol/L,表面张力为39 mN/m,具有较好的起泡性和稳泡性。

Synthesis and properties of a novel of ester-containing imidazole-based cationic gemini surfactants

A novel type of cationic ester-containing gemini surfactants called 1,3-bis(3-methylimidazolium)-2,2-bis(dodecanoatemethyl)-propane(EminC12) was synthesized with lauric acid,2,2-bis(bromomethyl)-1,3-propanediol and N-methylimidazole as the main starting materials.The main reaction includes esterification and quaternization.The optimum reaction process was ascertained as follows:n(lauric acid)∶ n(2,2-bis(bromomethyl)-1,3-propanediol)=2.2∶ 1,the reaction taking place at 115 ℃ for 7 h,with p-toluenesulfonic acid as catalyst and methylbenzene as the water absorbent.Under such conditions,the yield rate of 1,3-dibromine-2,2-bis(dodecanoatemethyl)-propane(DEC12) was 87%.In the quaternization process,the yield rate of the target product,which was identified by IR,elementary analysis and 1HNMR could reach 80% when the intermediate and N-methylimidazole reacted at 150 ℃ for 5 h.The critical micelle concentration(CMC) is 0.3 mmol/L and γCMC is 39 mN/m at 25 ℃ in aqueous solution.This new surfactant exhibits higher foaming ability and foam stability.