Effect of different VOPO 4 phase catalysts on oxidative dehydrogenation of cyclohexane to cyclohexene in acetic acid

Abstract

α I-VOPO 4, α II-VOPO 4 and β-VOPO 4 have been investigated as catalysts for the gas phase oxidative dehydrogenation (ODH) of cyclohexane to cyclohexene with the addition of acetic acid (HOAc) in the feeds in a fixed bed reactor. Different VOPO 4 phases showed different acidity and reducibility. β-VOPO 4 phase is more active than α I-VOPO 4 and α II-VOPO 4 in the ODH without acetic acid addition. In the presence of acetic acid, the acidity of the catalyst may play an important role in the ODH process. Due to higher acidity, α I-VOPO 4 phase catalyst gives better catalytic performances than α II-VOPO 4 and β-VOPO 4 for the ODH of cyclohexane by adding of acetic acid in the reactants.