有序立方介孔短孔道有机金属铑催化水介质清洁有机反应

Ordered cubic mesoporous short-channel Rh-organometal catalyst for water-medium clean organic reactions

绿色化学是实现化工生产源头控制的必由之路.水介质有机反应是重要的发展方向,可有效地去除有机溶剂挥发和排放造成的污染.通常采用均相催化剂,但由于其难以回收,导致成本较高,甚至存在重金属离子污染的风险.非均相催化可克服上述缺点,但催化效率较低,需要解决传质吸附和活性位微环境的问题.报道了一种新型的三维有序立方介孔短孔道有机金属铑(Rh)催化剂(PMO-Rh(I)),有机金属Rh均匀镶嵌于乙烷修饰的二氧化硅(SiO_(2))孔壁.所制备的催化剂在水介质Heck类反应中显示出高活性、优选择性和长寿命的特点,主要归因于其扩散吸附优化、Rh(I)活性位环境匹配及稳定性增强.

Green chemistry isan ultimate way to control pollution production of chemical reactions from the beginning,in which the water-mediumorganic reactions represent an important way to avoid the pollution of discharge and evaporation of organic solvents.Those reactions are usually performed by using homogeneous catalysts,which are difficult to recycle and reuse,leading to high cost and even the pollution of heavy metal ions.Heterogeneous catalysts can solve those problems,but they usually display low catalytic efficiencies due to the limits of diffusion,adsorption and microenvironment of active sites.This work developed a novel Rh-organometal catalyst(PMO-Rh(I))in three-dimensional ordered cubic mesporous short-channelswith Rh(I)organometal embedded into the-CH_(2)-CH_(2)-doped SiO_(2) wall.The as-prepared catalyst exhibited high activity,good selectivity and long lifetime for water-medium Heck-type reactions,which could be attributed to the improved diffusion,enhanced adsorption,matchable microenvironment of Rh(I)active sites and enhanced stability.