The oxidation of isobutane was investigated over various complex vanadium oxide catalysts. Mg2V2O7, MgV2O6, and Mg3V2O8 are effective catalysis for isobutene formation at >300°C. Cu2V2O7 and CaV2O6 showed intermediate activity and BiVO4 and Ca7V4O17 were slightly active. The active catalysts had relatively strong acidic sites, and H abstraction from the t-carbon of isobutane by acidic site was considered to be the initial and rate-determining step because a linear relationship was observed between the amount of acidic sites and the catalytic activity of the catalysts. The introduction of transition metals into the Mg sites of the Mg2V2O7 crystal lattice formed Mg1.8V2M0.2O7 (M = Mn, Cr, Fe, Co, Ni) catalysts. This substitution significantly promoted the catalytic activity without changing the selectivity for isobutene. Introduction of these transition metals increased the reactivity of lattice oxygen in Mg1.8V2M0.2O7 catalysts. Decreased WIF, increased the selectivity for isobutene to approaching 100%, suggesting that the initial reaction is the oxidative dehydrogenation of isobutane without parallel COx formation.
All Science Journal Classification (ASJC) codes
- Fuel Technology
- Energy Engineering and Power Technology