离子液体修饰磁性二氧化硅担载的Pd-Ru双功能催化剂的设计、合成及应用

The olefin metathesis Grubbs catalysts modified by ionic liquids are more active in ionic liquids than in conventional organic solvents, and the catalysts can be recycled for several times. However, this kind of catalyst requires large amount of expensive ionic liquid as solvent to maintain the high activity and recyclability. This project plans to design a new type of Grubbs catalyst by grafting ionic liquids and ionic liquid modified Grubbs catalysts onto the surface of silica particals with a magnetic Fe3O4 core.The activity of the catalyst can be improved by tuning the two-dimensional ionic liquid layer and it can be separated from the reaction mixture by magnetic adsorption. We will further immobilize palladium nano particales on the catalyst to form a Pd-Ru dual-functional(olefin metathesis-hydrogenation) catalyst. From an economic and environmental point of view, this catalyst will save a lot of expensive ionic liquid. The combination of ionic liquid layer and magnetic silica will not only increase the activity of the catalyst, but also increase the recyclability. Pd-Ru dual-function catalyst will achieve one-pot reaction of olefin metathesis and hydrogenation sequencely. The catalysts modified by chiral ionic liquids will be also designed and applied to asymmetric reactions.

离子液体修饰的Grubbs金属钌催化剂催化烯烃复分解反应时，在离子液体中比在传统有机溶剂中有更高的活性，并且催化剂可以多次回收再利用。然而，这种经离子液体改造的催化剂需用大量昂贵的离子液体做溶剂，才能保持高活性和实现回收再利用。本项目试图将离子液体和离子液体修饰的Grubbs金属钌催化剂共同固载到具有Fe3O4磁性核的二氧化硅表面，制备催化活性由二维离子液体层调控的、可通过磁性吸附分离的Grubbs型催化剂；并且进一步利用二维离子液体层对Pd纳米粒的稳定作用将其担载到二氧化硅表面，形成Pd-Ru双功能催化剂。该项目不仅可以节省大量的离子液体溶剂，实现经济、环保；离子液体层与磁性二氧化硅的结合不仅可以增加催化剂的活性，也将增加其回收利用性；形成的Pd-Ru双功能催化剂可以一锅（one-pot）实现烯烃复分解反应和催化氢化反应；试图引入的手性离子液体，将一般的有机反应扩展到不对称合成反应中。

离子液体修饰的Grubbs-Hoveyda金属钌卡宾催化剂分别担载到有二氧化硅包裹的、和没有二氧化硅包裹的磁性Fe3O4表面。这种磁性纳米粒子担载的催化剂在催化双烯扣环和偶联反应时，只用0.85mol%的金属钌催化剂就可以有效催化反应，催化活性可以和只用离子液体担载的催化剂的活性相媲美，而且可以通过磁铁吸附实现催化剂的回收再利用。有二氧化硅包裹的催化剂的重复利用性优于没有二氧化硅包裹的，可以重复利用14次。