The effects of microwaves on the catalyst preparation and the oxidation of o-xylene over a V₂O₅/SiO₂ system

With microwave irradiation, phthalic anhydride was obtained with a high yield of 67 mol% at ca. 563 K by the oxidation of o-xylene with air over V₂O₅/SiO₂ system. It is found that dispersion of V₂O₅ on SiO₂ is more homogeneous when the catalyst is prepared by microwave irradiating method. In the microwave catalytic process the optimum reactor bed temperature of the title reaction decreases to 563 K (653 K in the conventional process). The effects of the microwave electromagnetic field on the catalysts are discussed.