n-Butane dehydrogenation over mono and bimetallic MCM-41 catalysts under oxygen free atmosphere

The present study investigates the dehydrogenation of n-butane over mono (Cr or V) and bimetal (Cr-V) loaded MCM-41 catalysts. Wet impregnation technique was used, where the metal content maintained around 4 wt.%. The unique properties of bimetal supported catalysts were evaluated by means of XRD, N-2 adsorption, and temperature programmed analysis H-2-TPR and NH3-TPD. The mixed oxides Cr and V impregnated MCM-41 was tested for dehydrogenation of n-butane at different temperatures ranging 525-600 degrees C. The catalytic evaluation shows that Cr content of 1.2 wt.% and V content of 2.8 wt.% over MCM-41 designated as 1.2Cr2.8V/M-41 exhibited the highest butane conversion of 20.1% and butenes selectivity of 88.5% at 600 degrees C. Monometallic forms synthesized through hydrothermal (Cr-MCM-41) and impregnation route (3.5 wt.% Cr/MCM-41 and 3.8 wt.% V/MCM-41) were found to be less active for the dehydrogenation reaction. In the presence of CO2, the stability of 1.2Cr2.8V/M-41catalyst improved with n-butane conversion of 8.2% at 10 min to 6.5% at 180 min. The improved performance of bimetal catalysts can be correlated to synergetic effect of uniformly dispersed Cr-V-O mixed oxides over MCM-41, high reducibility and surface acidity. (C) 2012 Elsevier B. V. All rights reserved.