新型酯基咪唑类表面活性剂的合成与性能

Synthesis and Properties of a Novel Type of Ester-containing Imidazole-based Surfactants

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。

A novel type of cationic ester-containing gemini surfactants called 1, 3-bis （3- methylimidazolium）-2, 2-bis （ dodecanoatemethyl ）-propane （ EminC12 ） was synthesized with laurie aeid,2,2-bis（bromomethyl）-I ,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 （ laurie acid ） ： n [ 2,2-bis （ bromomethyl ） -1,3-propanediol~ = 2.2 ： 1, the reaction taking place at 115 ℃ for 7 h,with p-toluenesulfonie 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 TCMC is 39 mN/m at 25 ℃ in aqueous solution. This new surfactant exhibits higher foaming ability and foam stability.