负载硅离子液体的合成及其催化性能

Synthesis and catalytic properties of ionic liquids supported on silica

首先合成了氯代1-(2-羟乙基)-3-甲基咪唑离子液体[He MIM]Cl、溴代1-乙胺基-3-甲基咪唑离子液体[Ae MIM]Br和氯代1-羧乙基-3-甲基咪唑离子液体[Ce MIM]Cl 3种功能化咪唑离子液体,然后将这3种离子液体分别与正硅酸乙酯通过溶胶凝胶法制备了3种负载硅型离子液体[He MIM]Cl-Si、[Ae MIM]Br-Si和[Ce MIM]Cl-Si,并利用红外与XRD对其化学结构与结晶结构进行测定。再利用制备的离子液体催化环氧乙烷与二氧化碳合成碳酸乙烯酯。结果表明,离子液体负载硅后其催化性能明显提高,在较温和的条件下即可高效完成催化过程,且无聚酯或聚醚等副产物生成。其中,[Ce MIM]Cl-Si催化性能最好,在110℃、1.6 MPa催化条件下得到的转化率为99.2%,选择性为96.4%,产率为97.6%。

Three kinds of functionalized imidazolium ionic liquids,1-chloride（ 2-hydroxyethyl）-3-methyl imidazole ionic liquid [Hemim]Cl,1-bromide ethylamine-3-methyl imidazolium ionic liquid [Aemim] Br and 1-chloride carboxyethyl-3-methyl imidazolium ionic liquid [Cemim]Cl,are synthesized,then reacted with tetraethoxysilane by solgel method to prepare [Hemim]Cl-Si,[Aemim]Br-Si and [Cemim]Cl-Si. The crystal structures and chemical structures of the ionic liquids supported on silica are analyzed by FTIR and XRD. The obtained ionic liquids supported on silica are subsequently used to catalyze the reaction between epoxy ethane and carbon dioxide to achieve ethylene carbonate. The results show that the catalytic properties of ionic liquids supported on silica are obviously improved. The catalytic process can be accomplished under a milder condition,without formation of polyester,polyether or other by-products. Among three kinds of functionalized imidazolium ionic liquids,[Cemim]Cl-Si exhibits the best catalytic performance. The conversion rate,selectivity and yield of ethylene carbonate at 110℃ and 1. 6 MPa are 99. 2%,96. 4% and 97. 6%,respectively.