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离子液体型表面活性物质的合成及其性能的研究

Synthesis and Properties of Ionic Liquid Surfactants

【作者】 董莉莉

【导师】 刘雪锋;

【作者基本信息】 江南大学 , 应用化学, 2011, 硕士

【摘要】 离子液体(ILs)型表面活性剂是功能化离子液体和新型表面活性剂的交叉新品种,它同时具有表面活性剂和离子液体的某些特性,是国际上关于离子液体和表面活性剂交叉领域研究的新兴前沿热点之一。本论文以咪唑环为中心连接基、通过侧链基的不同设计,分别得到羟基功能化的ILs阳离子表面活性剂和两性型ILs表面活性剂。(1)羟基功能化的ILs阳离子表面活性剂氯化1-(2-羟乙基)-3-十二烷基咪唑([C2OHC12im]Cl)。采用咪唑与1-溴代十二烷、2-氯乙醇烷基化、季铵化的方法合成了[C2OHC12im]Cl;其分子结构特征经红外光谱、电喷雾质谱、元素分析和核磁共振谱等手段进行确证;分别采用表面张力法、电导率法和稳态荧光探针法测定[C2OHC12im]Cl的临界胶束浓度(CMC1),电导率法和稳态荧光探针法实验结果提示该表面活性剂具有奇特的第二临界胶束浓度(CMC2);NaX (X=Cl, Br, I)使其CMC值减小,并且阴离子的水化能力越弱,其CMC值降低趋势越强;同时,还使其吸附效率(pC20),在CMC处的表面压(ΠCMC),最大表面过剩(Γm)增加,分子最小截面积(Amin)减小;对于NaBr-[C2OHC12im]Cl体系而言,其CMC值随NaBr浓度变化呈对数关系;利用稳态荧光淬灭法分别得到[C2OHC12im]Cl水溶液和无机盐-[C2OHC12im]Cl体系胶束聚集数(Nm)随其浓度(C)的增加而增大,分别按指数和线性关系拟合方程,推导出其CMC (CMC1, CMC2, CMCx)相对应的临界胶束聚集数(Nm,c1, Nm,c2, Nm,cx) ,其中存在关系Nm,c1<Nm,cx<Nm,c2 ;对于NaBr-[C2OHC12im]Cl体系而言,其Nm随NaBr的浓度变化呈指数关系。(2)两性型ILs表面活性剂1-羧甲基-3-十二烷基咪唑内盐(CMDim)。采用咪唑与1-溴代十二烷、2-氯乙酸钠烷基化、季铵化的方法合成了产物;其分子结构特征经红外光谱、电喷雾质谱、元素分析和核磁共振谱等手段进行确证;Krafft点和等电点分别为18±0.2 oC和3.8±0.2;分别采用表面张力法、稳态荧光法测定CMC和Nm,结果表明:CMC和Γm值随pH增大而减小,pC20和Amin则相应增大,pH改变对ΠCMC影响不大;在pH=7条件下CMDim的Nm随其浓度增加而增大,分别按指数和线性关系方程拟合Nm随CMDim浓度变化的数学方程,并推导出相应的Nm,c值。

【Abstract】 Ionic liquids (ILs) surfactants possess many characteristics of both surfactants and ionic liquids. Recently, the synthesis and the surface activities of these novel surfactants have been one of the attractive topics in the fields of ILs and surfactants. Here, two novel ILs surfactants, a hydroxy-functional ILs cationic surfactant and a zwitterionic ILs surfactant, have been designed and synthesized using imidazole as the starting material.(1) A hydroxy-functionalized ILs cationic surfactant, namely 1-hydroxyethyl-3-dodecyl imidazolium chloride ([C2OHC12im]Cl). [C2OHC12im]Cl was synthesized using imidazole, 1-bromododecane and 2-chloroethanol via alkylation and quarter amination. The molecular structure was confirmed by means of fourier transform infrared spectroscopy, electrospray mass spectrometry, elemental analysis and nuclear magnetic resonance. The first critical micelle concentration (CMC1) was determinated by surface tension method, conductive method and steady-state fluorescence probe method. The experimental results show that [C2OHC12im]Cl had the second critical micelle concentration (CMC2). The sodium halides (NaX, X=Cl, Br, I) cause a decrease of CMC values. The smaller the hydration of the anion was, the smaller the CMC was. In the presence of NaX, the adsorption efficiency (pC20), the surface pressure at the CMC (ΠCMC) and the maximum surface excess (Γm) values increase, and the minimum molecular cross-sectional area (Amin) values decreases. For NaBr-[C2OHC12im]Cl systems, the relationship between CMC and the concentration of NaBr (CNaBr) is logarimic. Under the conditions of with or without NaX, the micelle aggregation number (Nm) increase with the concentration of [C2OHC12im]Cl (C) increasing. The relationship between Nm and C was fitted by power law and linear equation, respectively. Consequently, the critical micelle aggregation number (Nm,c) was deduced by the equations. In NaBr-[C2OHC12im]Cl system, the Nm exponentially grows with CNaBr increasing.(2) A zwitterionic ionic liquid surfactant, namely 1-carboxylmethyl-3-dodecyl imidazolium inner salt (CMDim). CMDim was prepared using imidazole, 1-bromododecane and sodium chloroacetate via alkylation and quarter amination. The molecular structure was confirmed by means of fourier transform infrared spectroscopy, electrospray mass spectrometry, elemental analysis and nuclear magnetic resonance. The Krafft point is 18±0.2 oC, and isoelectric point is 3.8±0.2. The critical micelle concentration (CMC) and the micelle aggregation number (Nm) were determinated by surface tension method and steady-state fluorescence probe method, respectively. The experimental results show that CMC andΓm values decrease, pC20 and Amin values increase,ΠCMC values unchanges with the pH values increasing. In pH=7 aqueous solution, the Nm increase with the concentration of CMDim (C) increasing. The relationship between Nm and C was fitted by power law and linear equation, respectively. Consequently, the critical micelle aggregation number (Nm,c) was deduced by the equations.

  • 【网络出版投稿人】 江南大学
  • 【网络出版年期】2011年 08期
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