基于纳米二氧化硅与MCM-41的两种多相钯催化剂的合成及其在Suzuki反应中的应用

摘要

Palladium compounds containing diphosphine ligand with N atom were immobilized on the surface of nano silica and MCM-41 respectively.The resulting two novel heterogeneous Pd catalysts SiO2@PNPPdCl2 (1) and MCM-41@PNPPdCl2(2) were fully characterized by SEM (EDX),TEM (SAED),XRD,FT-IR,ICP-Ms and TGA.Microstructure tests showed that the two kinds of nanoparticles have completely different structures,1 has an irregular sphere structure and 2 has a honeycomb structure.The catalytic performance of nanoparticles 1 and 2 under mild conditions with EtOH/H2O (v/v =3/2) as solvent in Suzuki coupling reaction was further studied.The two catalysts had good group tolerance,and their average yields in four cycles were 81％ (1) and 89％ (2) respectively.Their catalytic properties are also slightly different.The catalytic rate of catalyst 1 is much faster than that of 2,while catalyst 2 has better recycling performance.%含氮膦配体的钯配合物分别被负载于纳米二氧化硅和MCM-41表面.由此得到的两种新型多相钯催化剂SiO2@PNPPdCl2(1)和MCM-41@PNPPdCl2 (2)均通过SEM(EDX)、TEM(SAED)、XRD、FT-IR、ICP-MS和TGA等手段进行全面表征.微观结构表明,这两种纳米颗粒具有完全不同的结构,1为不规则球体,2具有蜂窝孔状结构.然后进一步研究了纳米粒子1和2在Suzuki偶联反应中以乙醇和水为溶剂的温和条件下的催化性能.研究显示两种催化剂均具有较好的基团耐受性,循环利用4次的平均产率分别为81％(1)和89％(2).它们的催化性能也略有不同,催化剂1的催化速率高于2,催化剂2具有较好的循环利用性能.