Oxidative dehydrogenation and aromatization of n-octane over VMgO catalysts obtained by using different MgO precursors and different precursor treatments

• Changing the MgO precursor and treatment gave different VMgO catalysts.
• These catalysts had differing properties.
• At iso-conversion the product distribution is better explained by surface acidity.
• Treating MgO precursor under vacuum induced positive effects on the resultant catalysts.

VMgO catalysts with a V2O5 loading of 15% were prepared by the wet impregnation method. Catalysts synthesis was carried out by employing different MgO precursors (MgC2O4 and Mg(OH)2) and different precursors treatments (under vacuum and under static air). The synthesized catalysts were characterized by ICP-OES, BET, powder XRD, SEM, EDX, 51V NMR, H2-TPR, and NH3-TPD. The catalysts were tested for the oxidative dehydrogenation of n-octane using a continuous flow fixed bed reactor at GHSV of 8000 h−1 and n-octane/O2 molar ratio of 0.8. Changing the above synthesis parameters led to the formation of catalysts with different morphologies, textural properties, and acidity. As a consequence, the results of the catalytic testing were also different, and treating the MgO precursors under vacuum induced a general positive effect on the catalytic performance. The aromatization of n-octane was predominantly via C1–C6 bonding.

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