新型Gemini咪唑表面活性剂的合成及表面性能

摘要

以2,2-双(溴甲基)-1,3-丙二醇为连接基合成了新型的连接基为枝状的Gemini咪唑表面活性剂2,4-二(溴化-3-烷基咪唑)-1,3-丙二醇([cn-P-Cnim] Br2,n=10,12,14).产物经核磁共振氢谱(1H NMR)、红外(IR)光谱和元素分析等进行了分析,证明所得产物即为目标产物.通过表面张力法和电导法测量其表面活性并计算胶束形成热力学参数(△G(φ)m,△H(φ)m,△S(φ)m).结果表明,25℃时3种表面活性剂均具有很高的表面活性,胶束的形成是自发的熵驱动过程.%Gemini imidazolium surfactants 2,4-[bis(3-alkylimidazolium-l-yl)bromide]-l ,3-propanediol ( [Cn-P-Cnim]Br2, n =10, 12, 14) were synthesized with dibromoneopenty glycol as the spacer. The surfactants were characterized via 1H NMR spectra, IR spectra and elemental analysis, and the results prove that they are all the objective products. The surface activity and thermodynamic properties of micellization of the surfactants were characterized by surface tension and electrical conductivity measurements. The values of critical micelle concentration ( cmc) , γcmc, Γmax , Amin, pc20 and πcmc derived from surface tension measurement at 25℃ suggest that the surface activities of [Cn-P-Cnim]Br2 are high. While the thermodynamic parameters of micellization ( ΔGθm , ΔHθm, ΔSθm ) of all the surfactants derived from electrical conductivity indicate that the formation of micelles is spontaneous and the micellization of [ Cn-P-Cnim]Br2 is entropy-driven.