Octenes and Aromatics from the Oxidative Dehydrogenation of n-Octane over Co/TiO2 Catalysts

Abstract

Titania supported cobalt catalysts with cobalt loadings between 5 and 25 wt% were synthesised via the wet impregnation technique and characterized by XRD, XPS, BET, SEM-EDX, TEM, ICP, TGA, Laser Raman and TPR analysis. Catalytic testing was carried out at a GHSV of 4,000 h−1 in a fixed bed reactor at atmospheric pressure, with air as the oxidant and nitrogen as the diluent from 350 to 550 °C. An n-octane to oxygen molar ratio of 1:1 was maintained. The dominant products were found to be the octenes, C8 aromatics and carbon oxides, with selectivities of up to 80 % to the former two products. Comparative studies based on the different metal loadings indicate that higher cobalt content enhanced the selectivities to octenes. COx formation was found to decrease significantly with an increase in temperature, as the pathway to octenes and C8 aromatics was favoured. TiO2 based cobalt catalysts transform n-octane, a model FT product, to octenes and C8 aromatics via oxidative dehydrogenation in a continuous flow fixed bed reactor with air as the oxidant and nitrogen the diluent, spanning the temperature range of 350–550 °C at atmospheric pressure.