硅胶固定化离子液体的合成与催化醚化性能

Synthesis and Catalyzed Etherification of Silica-immobilized Ionic Liquids

室温离子液体是近年来开发并逐渐应用于有机反应中的绿色溶剂和新型催化剂。将离子液体固定于固相载体上可大大减少离子液体在使用过程中的流失。以硅胶为载体,KH-560为偶联剂合成了烷基硅烷化环氧硅胶,再与N-甲基咪唑在浓硫酸作用下制备硅胶固定化离子液体。探讨了在H+促进下的离子液体对醚化反应的催化性能。实验表明,当仅用浓硫酸催化合成正丁醚时,其产率为34%,当体系中仅加入0.5g离子液体和少量浓盐酸时产率则提高至42%,合成固定化离子液体易回收,可重复利用,当重复使用5次后,正丁醚的产率仍可达37.5%。

Room temperature ionic liquids （RTIL） were recently developed and gradually applied to various sorts of reactions as green solvents and novel catalysts. The loss of ionic liquids can be reduced by being confined to solid supports in the using process. In the concentrated sulfuric acid conditions, silica gel confined ionic liquids could be prepared by the reaction of N-methylimidazoe with alkyl epoxy silica gel, which was synthesized by silica gel as solid support and KH-560 as the coupling agent. The catalytic function of the ionic liquid with H^＋ was also studied in the etherification reaction. The results showed that the yield of n-butyl ether was approximately 34 % under the concentrated sulfuric acid. While 0.5 g the ionic liquid and 4mL concentrated HCl were joined, the yield was up to 42 %. At the same time, the ionic liquid was easily to recycle. The remaining ionic liquid catalytic system could be reused without much loss in activities. After using 5 times, the yield of n-butyl ether still reached 37.5 %.