Partial oxidation of benzene catalysed by heteropolycompounds

Vanadium substituted phosphomolybdic acids could hydroxylate benzene with nearly 100% selectivity at appreciable conversion levels in the presence of oxidising agents like H2O2 and CH3COOOH. There appears to be a correlation, for the liquid phase, between phenol yield and its rate of formation with vanadium content in the phosphomolybdic acid. Unfortunately, these materials do not show the same activity in gas-phase with N2O as oxidant. Therefore, it has been demonstrated that the high acidity of these solids is not involved in the reaction pathway.