吸电子基团诱导的离子液体的快速蒸馏回收研究

项目名称： 吸电子基团诱导的离子液体的快速蒸馏回收研究

项目编号： No.21503050

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 陈正件

作者单位： 贵州师范学院

项目金额： 21万元

中文摘要： 离子液体由于挥发性极低，被视为新一代的“绿色溶剂”。但正因为如此，离子液体不能像传统的有机溶剂那样通过简单的蒸馏就能被纯化回收，不利于其大规模应用。本项目拟利用可逆的季铵烷基化反应实现离子液体的快速蒸馏回收，即将离子液体热裂解成分子前体化合物的同时进行蒸馏，所得的馏分能自发发生烷基化反应，因此最终得到的蒸馏物是离子液体，不需要后处理即可重复使用。为此，我们在阳离子的一个侧链上引入吸电子基团（如+N-CH2-EWG）。一方面EWG能提高该侧链上亚甲基的亲电性，使得与阴离子（X-）的热裂解脱烷基化反应集中发生在这一点上，减少副产物的生成；另一方面EWG能提高X-CH2-EWG的反应活性，使之能与另一热分解产物（如叔胺）自发反应重新生成离子液体。我们将具体考察阴/阳离子与吸电子基团等结构变化、真空度、温度与加热方式（传统或微波）对蒸馏回收效果的影响，以及离子液体在实际应用之后的蒸馏回收情况。

中文关键词： 离子液体；吸电子基团；季铵烷基化；可逆性；蒸馏

英文摘要： Ionic liquids are considered as a new generation of “green solvent”, due to their extremely low volatility. But precisely because of this, ionic liquids can’t be easily recovered by simple distillation like traditional organic solvents, limiting their large-scale application. The aim of this project is to achieve the rapid distillation of ionic liquids by use of reversible quaternization (alkylation) reaction. Namely, when an ionic liquid is thermally decomposed into molecular precursors, the precursors are collected by distillation, and the precursors can react spontaneously to regenerate the ionic liquid, so that the final distillate is ionic liquid, requiring no post processing. For this purpose, an electron withdrawing group is introduced into a side chain in cation (e.g. +N-CH2-EWG). On the one hand, EWG enhances the electrophilicity of the methylene in this side chain, so that the pyrolysis dealkylation with anion (X-) will be concentrated in this point, to reduce by-product formation; on the other hand, EWG can increase the reactivity of X-CH2-EWG precursor, so that it can react spontaneously with another pyrolysis product (such as tertiary amine) to regenerate ionic liquid. We will specifically study the distillation recovery of ionic liquids in different conditions of anion/cation combinations, electron withdrawing groups, the degree of vacuum, temperature and heating methods (conventional and microwave), and after a practical application.

英文关键词： ionic liquids;electron withdrawing group;quaternization alkylation;reversibility;distillation