OXIDATION OF CYCLOHEXENE WITH HYDROGEN-PEROXIDE CATALYZED BY HETEROPOLY COMPOUNDS

Oxidation of cyclohexene by hydrogen peroxide was investigated by using as catalysts various heteropoly compounds having different central and poly atoms. The reaction scheme was proposed based on the time course of the oxidation of cyclohexene as well as the reactivity of the products, i.e., cyclohexene oxide and trans-1,2-cyclohexanediol, and the stoichiometry of the oxidation of cyclohexene and cyclohexene oxide. The catalytic activity and selectivity of 12-molybdophosphoric acid for the oxidation of cyclohexene was affected by the presence of water. The catalytic activity of heteropoly acid increased with the increase in the valence of the central atom ; B3+ < Si4+ < C4+ less-than-or-equal-to P5+, and as for poly atom ; Mo > W. These trends indicate that the catalytic activity increases with the increase of the redox potential of the polyanion.