Synthesis, characterization & reactions of vanadium substituted 12-molybdo heteropoly acids

Abstract

12-Phosphomolybdic acid and its mono-, di-, and tri- substituted vanadium analogues have been synthesized and characterized by instrumental techniques. The catalytic activity of these compounds has been studied and compared for the oxidation of cyclohexanol to cyclohexanone using hydrogen peroxide as the co-oxidant. It has been found that at low concentrations of hydrogen peroxide the catalytic activity is lowered as the number of vanadium atoms is increased, but when excess of hydrogen peroxide is used the catalytic activity is found to follow the reverse trend. The results are explainable in terms of the V⁴⁺ content in the compounds.