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合成了联结基团分别为亚甲基链及含羟基亚甲基链的两种季铵盐Gemini表面活性剂,即C12-3-C12.2Br及C12-3(OH)-C12.2Cl。用红外光谱、核磁共振及元素分析对它们的结构进行了鉴定,并对影响反应的因素进行了研究,得出了合成C12-3-C12.2Br的最佳条件为:n(N,N-二甲基十二烷基胺)∶n(1,3-二溴丙烷)=2.2∶1.0,以乙醇作溶剂,在回流温度下反应24 h,产率可达80%以上。合成C12-3(OH)-C12.2Cl的最佳条件为n(二甲基十二烷基叔胺)∶n(二甲基十二烷基叔胺盐酸盐)∶n(环氧氯丙烷)=2.0∶1.0∶1.0,以正丙醇为溶剂,在回流温度下反应3 h,产率可达94.5%以上。测定了它们的表面张力γ、临界胶束浓度cmc及降低水溶液表面张力的效率C20,结果表明:与相应的单头基单烷烃链表面活性剂相比,Gemini表面活性剂具有很低的cmc和很强的表面活性,联结基团对其性能有较大的影响。
Two kinds of quaternary ammonium salt Gemini surfactants, C12-3-C12.2Br and C12-3 (OH) -C12.2Cl, were synthesized. They were methylene chain and hydroxyl-containing methylene chain respectively. Their structures were identified by IR, 1H NMR and elemental analysis, and the factors affecting the reaction were studied. The optimum conditions for synthesizing C12-3-C12.2Br were as follows: n (N, N- Dimethyldodecylamine): n (1,3-dibromopropane) = 2.2:1.0, using ethanol as solvent, the reaction was carried out at reflux temperature for 24 h, and the yield could reach over 80%. The optimum conditions for the synthesis of C12-3 (OH) -C12.2Cl are n (dimethyldodecyl tertiary amine): n (dimethyldodecyl tertiary amine hydrochloride): n (epichlorohydrin Propane) = 2.0: 1.0: 1.0. With n-propanol as solvent, the reaction was carried out at reflux temperature for 3 h, and the yield was up to 94.5%. The surface tension γ, the critical micelle concentration cmc and the efficiency C20 of reducing the surface tension of the aqueous solution were measured. The results show that the Gemini surfactant has a very low cmc and a lower surface area than the corresponding monoalkylmonoalkyl chain surfactants Strong surface activity, the coupling group has a greater impact on its performance.