Oxidation of isobutane over Mo-V-Sb mixed oxide catalyst

The catalytic performances of Mo-V-Sb mixed oxide catalysts have been studi ed in the selective oxidation of isobutane into methacrolein. V-Sb mixed ox ide showed the activity for oxidative dehydrogenation of isobutane to isobu tene. The selectivity to methacrolein increased by the addition of molybden um species to the V-Sb mixed oxide catalyst. In a series of Mo-V-Sb oxide c atalysts, Mo1V1Sb10Ox exhibited the highest selectivity to methacrolein at 440 degrees C. The structure analyses by XRD, laser Raman spectroscopy and XPS showed the coexistence of highly dispersed molybdenum suboxide, VSbO4 a nd alpha-Sb2O4 phases in the Mo1V1Sb10Ox. The high catalytic activity of Mo 1V1Sb10Ox can be explained by the bifunctional mechanism of highly disperse d molybdenum suboxide and VSbO4 phases. It is likely that the oxidative deh ydrogenation of isobutane proceeds on the VSbO4 phase followed by the oxida tion of isobutene into methacrolein on the molybdenum suboxide phase.