采用等体积浸渍法制备了介孔分子筛SiMCM-41负载的ZnCl2、ZnO、FeCl3和Fe2O3催化剂,并用于苯酚与二氧化碳在CCl4溶液中合成碳酸二苯酯.采用29SiNMR、ICP、XRD和UV-Raman等技术对催化剂的结构性质、活性组分和载体间的相互作用以及反应前后催化剂结构变化等进行了研究.结果表明,载体SiMCM-41在反应过程中表现出较高的稳定性,ZnCl2、ZnO、FeCl3及Fe2O3负载到介孔SiMCM-41上,金属离子和载体表面硅羟基结合生成固载型活性中心,防止了金属离子在反应过程中从催化剂表面的流失.以二氧化碳、苯酚和碳酸钾为原料,在四氯化碳溶液中反应合成碳酸二苯酯(DPC)时,锌负载催化剂具有较高的催化活性和DPC选择性.
Mesoporous SiMCM-41 supported ZnCl2, ZnO, FeCl3 and Fe2O3 catalysts prepared through impregnation were characterized by 29SiNMR, ICP, XRD and UV-Raman. Their behaviors on the synthesis of diphenyl carbonate (DPC) from phenol and CO2 in CCl4 were examined. The dispersion of active components, the interaction between metal and support, and changes in catalyst structure during reaction were investigated. The results proved that mesoporous SiMCM-41 was stable during reaction; when ZnCl2, ZnO, FeCl3 and Fe2O3 were loaded into SiMCM-41, the activated sites were bounded on the surface of support by the reaction with silanol groups of pore wall in the molecular sieves, which prevented them from leaching out of catalyst. Among the catalysts examined, ZnO/SiMCM-41 exhibited the highest yield and selectivity for DPC synthesis.