On the Effect of Hydrocarbon/Oxygen Ratios During the Dehydrogenation of n-Octane Over a VMgO Catalyst

Abstract

A vanadium–magnesium oxide catalyst (VMgO) with a V2O5 concentration of 15% by weight was employed for the oxidative dehydrogenation of n-octane to produce the corresponding linear octenes and C8 aromatics. The catalyst was synthesized by the wet impregnation method, and was characterized by in situ XRD, TGA-DSC, and 51V MAS NMR. The used catalysts were characterized by powder XRD, BET, pore volume analysis, SEM, EDX, ICP-OES, and 15V MAS NMR. The catalytic testing was carried out at different n-octane/O2 molar ratios (viz. 0.1, 0.4, 0.8, 1.2, and 1.6) at a GHSV of 8,000 h−1 in a continuous flow fixed bed reactor. The results showed that the catalytic performance with regard to both activity and selectivity was very sensitive to the strength of the oxidative environment (n-octane to oxygen ratio). No phasic changes were observed in the used catalysts. However, some textural changes were induced by the catalytic testing.