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

Abstract

A series of Ru/Al 2 O 3 /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-RuO 2 , 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.

Promotional Role of Surface Defects on Carbon‐Supported Ruthenium‐Based Catalysts in the Transfer Hydrogenation of Furfural

“…For the reduced Co/C sample, the first small peak at approximately 405 °C is assigned to the reduction of surface Co 3+ species, the second peak at approximately 541 °C represents the reduction of Co 3+ to Co 2+ species in the bulk phase, and the third peak at approximately 643 °C is associated with the further reduction of Co 2+ to Co 0 species . In the case of the Co‐Ru/C sample, a small peak at approximately 150 °C is ascribed to the further reduction of cationic Ru species . Interestingly, with the addition of Ru, the reduction of Co species shifts to lower temperatures, presumably because of the hydrogen spillover from the reduced Ru, which reduces cobalt oxide species easily .…”

Surface Species of Supported Ruthenium Catalysts in Selective Hydrogenation of Levulinic Esters for Bio-Refinery Application

“…While in case of alumina supported Ru catalyst, sharp diffraction peaks with higher intensities were observed due to highly crystalline nature of the sample. In all the samples no characteristic peaks of Ru were observed indicating either very high dispersion of Ru and/or Ru being diffused in the bulk matrix of the support [19].…”

Selective Hydrogenation of Benzene to Cyclohexene over 2Ru/La2O3‐ZnO Catalyst without Additional Modifiers

“…The decreasing performance of the catalyst at ah igher reduction temperature may be ar esult of the agglomeration of ruthenium particles. [14] In conclusion, ar eduction temperature of 400 8Cl eads to av ery active and highly effective catalyst for the formation of cyclohexenew ithout any further additives.…”