Catalytic performance of chromium oxide supported on Al2O3 in oxidative dehydrogenation of isobutane to isobutene

In this study, the performance of chromium oxide catalysts supported on Al2O3 was evaluated. The effects of the percent loading of Cr on Al2O3 and the pretreatment conditions on the activity and the selectivity of the catalysts in the oxidative dehydrogenation of i-C4H10 to i-C4H8 were also tested. Different types of Al2O3 were tested as supports for chromium oxide, and the activity and selectivity of these samples were correlated with the alumina properties. The obtained results show that the optimum loading of Cr on Al2O3 lies between 5 and 15%. Also, it has been observed that the calcination temperature affects the conversion at lower reaction temperatures, whereas its influence on product selectivity is limited by O-2 availability in the reaction mixture. The catalyst samples were characterized by FTIR and XPS measurements. The XPS analysis confirmed the presence of Cr6+ and Cr3+ On the surface of the catalyst. Cr3+ was dominant in the spent catalyst.