负载型TiO_2催化剂的制备及其酯交换反应性能

Preparation and Property of Supported Titania Catalysts for Transesterification of Dimethyl Oxalate with Phenol

采用水解法制备负载型TiO2／SiO2催化剂,用于苯酚和草酸二甲酯酯交换反应．通过考察催化剂焙烧温 度、载体粒径、催化剂用量、活性组分负载量和反应时间等因素对该酯交换反应的影响,确定出较佳的催化剂制备 工艺及反应条件．负载型氧化钛催化剂在该酯交换反应中表现出活性好、选择性高、催化剂易分离回收等优点．以 550℃焙烧的TiO2／SiO2为酯交换催化剂,TiO2负载量为13％,反应时间2h,反应温度180℃,草酸二甲酯的转化 率、甲基苯基草酸酯和草酸二苯酯的选择性分别为53．1％、72．1％和27．3％．

The transesterification of dimethyl oxalate （DMO） with phenol over TiO2/SiO2 catalysts was conducted to produce methyl phenyl oxalate（MPO） and diphenyl oxalate（DPO）. The TiO2/SiO2 catalysts prepared by wet impregnation of anhydrous ethanol solutions of tetrabutyl titanate showed high activity and excellent selectivity for the transesterification and good separability for reclaim. Various factors affecting the transesterification of DMO with phenol, such as calcination temperature, particle size of support, catalyst amount, TiO2 loading amount, and reaction time, were investigated. The study showed that the optimum calcination temperature for TiO2/SiO2 was 550 ℃. 53.1% conversion of DMO, 72.1% and 27.3% selectivity to MPO and DPO respectively, were obtained after 2-hour reaction at 180 ℃ with 13% TiO2 loading and in the presence of TiO2/SiO2 calcinated at the above optimum temperature.