Reactivity and stability of vanadium oxide catalysts for the oxidation of butan-2-ol by hydrogen peroxide Original Research Article

Vanadium oxide catalysts supported on titanium oxide have been tested as catalysts for the selective oxidation of butan-2-ol to methylethylketone by hydrogen peroxide at 90°C with a mixture of acetone and water as solvent. A range of catalyst preparation methods were used including wet impregnation and grafting and a number of unsupported oxides were also tested. The main side product observed was acetic acid, probably derived from oxidation of the enol form of methylethylketone. The selectivity of alcohol utilization was always better than the corresponding value for oxidant utilization for all catalysts studied and at all conversion levels. None of the catalysts tested were stable to leaching in the reaction environment. A steady state vanadium concentration became established in the reaction medium a short time after the reaction started. An attempt was made to differentiate between the contribution to the observed catalysis by the homogeneous and heterogeneous forms of vanadium present in the reactor. No correlation was observed between the amount of dissolved vanadium species and the catalytic activity, but there was a correlation between the activity and the total amount of vanadium species present. In addition, the selectivity improved as the dispersion of the vanadium oxide on the surface of the titania increased.