Anaerobic oxidation of isobutane was studied using MgV2O6, Mg2V2O7 and Mg3V2O8. Isobutene, a small amount of COx, and trace amount of oxygen containing compounds were formed. CO2 Was formed mainly at the beginning of the reaction and decreased with reaction time. Catalytic activity of Mg2V2O7 was slightly higher than that of MgV2O6 but the CO., formation over MgV2O6 was more than over Mg2V2O7. Mg3V2O8 was the least active. Therefore, Mg2V2O7 is the most suitable for oxidative hydrogenation of isobutane under the anaerobic reaction conditions. The equilibration between O-16(2) and O-18(2) over MgV2O6 was faster than over Mg2V2O7 or Mg3V2O8 at 673 K. The rate of equilibration between O-18(2) and lattice oxygen over MgV2O6 was similar to that over Mg2V2O7, which was faster than over Mg3V2O8. Highest yield of isobutene formation over Mg2V2O7 would come from the character of Mg2V2O7, in which mobility of the lattice oxygen is great but surface reaction of isobutane was not so fast. Higher activity for isobutene formation may come from the nature Of Mg2V2O7, of which mobility of the lattice oxygen is great but surface reaction of isobutane was not so much fast. Mn, Cr, Fe, Ni and Co can be introduced into Mg2V2O7 to give a single phase. Substitution of Co, Cu and Cr for Mg increased the activity Of Mg2V2O7 for isobutane oxidation and substitution of Ni and Mn scarcely affected the activity but substitution of Fe and Zn decreased the activity. Substitution of all the metal ions slightly increased the isobutene selectivity. MgO, MgV2O4 and Mg3V2O8 were observed in the sample after the anaerobic oxidation of isobutane. Cu containing catalyst was reduced to give Cu metal. (c) 2005 Elsevier B.V. All rights reserved.