苯甲酸气相加氢制苯甲醛负载型CeO2／Al2O3催化剂的研究

Hydrogenation of Benzoic Acid to Benzaldehyde over CeO_2/Al_2O_3 Catalysts

分别采用浸渍法和共沉淀法制备了一系列CeO2/Al2O3催化剂,并考察了它们在苯甲酸加氢制备苯甲醛反应中的催化性能。结果表明,共沉淀法制备的催化剂的催化性能优于浸渍法制备的催化剂。采用共沉淀法制备催化剂时,焙烧温度为600℃和CeO2负载量为40%时的催化剂性能较好,进行苯甲酸加氢反应时,苯甲酸转化率可达98.4%,苯甲醛的选择性和收率分别为93.7%和92.2%。共沉淀法制得的催化剂在反应过程中因产生积炭而失活,再生后能恢复活性。对两种方法制备的催化剂分析,发现催化剂比表面、CeO2晶粒大小和CeO2在载体表面的分散性是造成活性不同的根本原因。

A series methods respectively. of CeO2/Al2O3 catalysts were prepared by coprecipitation and impregnation The catalytic performance for hydrogenation of benzoic acid to benzaldehyde of catalysts prepared by coprecipitation method was better than that of cayalystys prepared by impregnation method. The optimal conditions of CeO2/Al2O3 catalysts prepared by coprecipitation method were that the mass fraction of CeO2 in CeO2/Al2O3 was 40% and calcination temperature was 600 ℃. The benzoic acid conversion was 98.4%, and the selectivity and the yield of benzaldehyde were 93.7%and 92.2%, respectively, when the catalysts prepared under the optimal conditions were used for hydrogenation of benzoic acid to benzaldehyde. By comparing the catalysts prepared by different methods, it was found that the surface, crystalline size and CeO2 dispersion were the main reasons for the difference of catalytic performance.