REACTIVITY AND STABILITY OF VANADIUM-OXIDE CATALYSTS FOR THE OXIDATION OF BUTAN-2-OL BY HYDROGEN-PEROXIDE

Vanadium oxide catalysts supported on titanium oxide have been tested as catalysts for the selective oxidation of butan-2-ol to methylethylk etone by hydrogen peroxide at 90 degrees C with a mixture of acetone a nd water as solvent. A range of catalyst preparation methods were used including wet impregnation and grafting and a number of unsupported o xides were also tested. The main side product observed was acetic acid , probably derived from oxidation of the enol form of methylethylketon e. The selectivity of alcohol utilization was always better than the c orresponding value for oxidant utilization for all catalysts studied a nd at all conversion levels. None of the catalysts tested were stable to leaching in the reaction environment. A steady state vanadium conce ntration became established in the reaction medium a shea time after t he reaction started. An attempt was made to differentiate between the contribution to the observed catalysis by the homogeneous and heteroge neous forms of vanadium present in the reactor. No correlation was obs erved between the amount of dissolved vanadium species and the catalyt ic 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 th e titania increased.