Preparation and Characterization of Ru/Al2O3/Cordierite Monolithic Catalysts for Selective Hydrogenation of Benzene to Cyclohexene

A series of Ru/Al2O3/cordierite monolithic catalysts were prepared and characterized by BET, XRD, TPR, TEM and SEM-EDAX. The catalytic performances in selective hydrogenation of benzene to cyclohexene were investigated in a continuous fixed-bed reactor. The preparation conditions significantly influence morphology, particle size, and surface area of the catalyst, subsequently affecting the catalytic performances. It was found that higher calcination temperature of the Ru-based monolithic catalyst led to the conglomeration and crystallite growth of the t-RuO2, which will decrease the catalytic activity. The lower thickness and the larger pore size of the alumina washcoating layer are the preferential choices to obtain higher cyclohexene selectivity due to the improved internal mass transfer of cyclohexene. It was also found that high ruthenium loading resulted in deep hydrogenation of cyclohexene. Moreover, the reduction temperature was optimized to 473 K and excess high temperature led to the deterioration of both activity and cyclohexene selectivity.