摘要
研究了在不同焙烧温度下, Cr3+修饰ZrO2催化剂的晶相变化, 以及不同晶相催化剂对苯甲酸加氢反应性能的影响. 结果发现400℃焙烧主要得四方(t)晶相ZrO2, 600℃焙烧主要得单斜(m)晶相, 并且m- ZrO2催化剂是决定苯甲醛选择性的主要因素. 同时还研究了以质量分数为25%的浓氨水作沉淀剂, 不同ZrOCl2·8H2O水溶液浓度和不同Cr3+与Zr4+摩尔比情况下的苯甲酸加氢制苯甲醛的反应性能. 从6组实验中优选出了一有较好性能的催化剂, 并且用这一催化剂再进行每次半小时的催化反应, 实验发现: 催化剂活性随反应次数的增加而降低, 但它们的选择性维持在95%左右, 失活后的催化剂进行再焙烧后可以恢复其活性, 在失活后的第二次焙烧时活性较高, 焙烧后的催化剂催化选择性维持在90%左右.
The change of crystal phases of Cr3+-modified ZrO2 catalysts under different calcination temperatureand the effect of the different catalysts with monoclinic and tetragonal structures on the hydrogenation ofbenzoic acid to benzaldehyde are studied. m-ZrO2 is easily prepared under 600℃, which is the major factor ofselectivity of benzaldehyde. Moreover, the catalytic reaction is also studied with catalysts of Cr3+-modified ZrO2prepared in 25% concentrated ammonia water adjusting the different concentration of solution and the differentmolar ratio of Cr3+ and Zr4+. Every reaction time is half an hour. The best one of these catalysts is selected.Theresults of the reaction with the selected catalyst show that the activity of the catalyst decreases when the time ofusing catalyst increases ,but their selectivity is about 95%.The deactivited catalysts can be reactivated undercalcination, during which the activity is higher and after which the selectivity remains about 90%.
出处
《昆明理工大学学报（理工版）》
2003年第3期146-149,共4页
Journal of Kunming University of Science and Technology(Natural Science Edition)
