金属有机多面体基包覆型微球制备及CO2环加成反应

Preparation of coated microsphere based upon metal organic polyhedra for CO2 cycloaddition reaction

采用原位合成法在铜基海藻酸-壳聚糖-SiO2(Cu-ALG-CS-SiO2)内部生长金属有机多面体(MOP),制备MOP基包覆型微球MOP-ALG-CS-SiO2。通过X线衍射(XRD)、N2吸附-脱附、透射电子显微镜(TEM)等方法对MOP-ALG-CS-SiO2的晶形、孔径和形貌进行分析并考察MOP-ALG-CS-SiO2催化环氧化合物与CO2环加成制备环状碳酸酯的反应性能。结果表明:MOP-ALG-CS-SiO2具有无定形的介孔结构,MOP在MOP-ALG-CS-SiO2中高度分散,解决了MOP基复合材料中普遍存在的稳定性和分散性不好的问题。MOP-ALG-CS-SiO2在催化环氧丙烷与CO2环加成反应中,环氧丙烷转化率为84.1%、碳酸丙烯酯选择性为99.7%,催化性能优于MOP、MOP-ALG-CS和HKUST-1。此外,MOP-ALG-CS-SiO2在催化其他类型环氧化物与CO2环加成反应中均表现出较高的催化活性和产物选择性。

Coated microspheres based upon metal organic polyhedra(MOP)were prepared by in-situ synthesis in which MOP grew in the copper-based alginate-chitosan-SiO2(Cu-ALG-CS-SiO2)microspheres.The crystal form,pore size and morphology of MOP-ALG-CS-SiO2 were characterized by X-ray diffraction(XRD),N2 adsorption-desorption and transmission electron microscopy(TEM).The catalytic activity of MOP-ALG-CS-SiO2 was evaluated by the CO2 cycloadditon with epoxides.Results showed that MOP-ALG-CS-SiO2 had an amorphous mesoporous structure and MOP were highly dispersed within the microspheres,which solved the problems of poor stability and aggregation in the MOP-based composites.MOP-ALG-CS-SiO2 had better catalytic activity than MOP,MOP-ALG-CS and HKUST-1 in the CO2cycloaddition with propylene oxide.The conversion of propylene oxide and the selectivity of propylene carbonate were 84.1%and 99.7%,respectively.In addition,MOP-ALG-CS-SiO2exhibited excellent catalytic activity for CO2 cycloaddition with other epoxides.