功能化离子液体在室温下催化醛(酮)与二元醇的缩合反应

Acetalization of aldehydes(ketones) with diols catalyzed by functional ionic liquids under room-temperature

采用功能化离子液体1-甲基-3-丙磺酸基咪唑盐作为溶剂/催化剂双功能体系,通过探针反应,固定原料环己酮与离子液体催化剂的摩尔比为50∶1进行工艺参数的优化,得到优化工艺条件为:n(环己酮)∶n(1,2-丙二醇)=1∶1.5,在20℃条件下反应0.1 h可以得到缩合产物,转化率大于97%。研究了该催化剂对其他醛(酮)与二元醇的缩合反应的催化性能,结果表明,该工艺无需有机溶剂及脱水剂,反应结束产物与催化体系分层,通过倾析便可得到产物,简化了分离过程且离子液体可以循环使用。

Some functional ionic liquids （FILs） composed of 1 - methyl - 3 - propane sulfo - imidazolium salts were synthesized and used as solvent - catalyst dual system for aeetalization of aldehydes （ketones） with diols. The model reaction was carried out based upon molar ratio of raw material cyelohexanone and the FILs catalyst as 50： 1. The optimized conditions of the condensation reaction were identified as ： 1 ： 1.5 molar ratio of cyclohexanone and 1,2 - propanediol, under reaction temperature 20 ℃for 0.1 h. The eonversion achieves 97% and the reaction process is free of any organic solvent and water stripping agent. The condensation reactions of the other aldehydes （ketones） with other diols were also explored. After completion of the reaction, the product can be separated from the catalyst simply by decantation, and the catalyst can be recycled and reused for several times without noticeable decreasing of activity.