新型酯基咪唑类表面活性剂的合成与性能

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

摘要:

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），结果表明，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5 h，目标产物产率可达80 %，产物结构通过元素分析、IR、1H NMR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。

Abstract:

The target product 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.The main reaction includes esterification and quaternization.The reaction process was studied as follows: n (lauric acid) ／n(2,2-bis(bromomethyl)-1,3-propanediol)=2.2:1,reacted at 115 ℃ for 7 h , with p-toluenesulfonic acid as catalyst and methylbenzene as the water absorbent,the yield rate of 1,3-dibromine-2,2-bis(dodecanoatemethyl)-propane（DEC12） was 87 %.The quaternization conditions: the yield rate of target product which was identified by IR、elementary analysis and 1H NMR could reach to 80 % when the intermediate and N-methylimidazole reacted at 150 ℃ for 5 h.The critical micelle concentration of CMC is 0.3 mmol／L and γcmc is 39 mN／m at 25 ℃.This new surfactant shows higher foaming and stability.