Effects of microwaves on selective oxidation of toluene to benzoic acid over a V2O5/TiO2 system

Abstract Two series of catalysts, V 2 O 5 /TiO 2 and modified V 2 O 5 /TiO 2 , were prepared with a conventional impregnation method. They were tested in the selective oxidation of toluene to benzoic acid under microwave irradiation. The reaction conditions were optimized over V 2 O 5 /TiO 2 . It was found that in the microwave catalytic process the optimum reactor bed temperature of the titled reaction decreases to 500 K (600 K in the conventional process). The modification of V 2 O 5 /TiO 2 with MoO 3 , WO 3 , Nb 2 O 5 or Ta 2 O 5 , which has no negative influence on the reaction in the conventional catalytic process, can greatly promote the catalytic activities in the microwave process, leading to a high yield of benzoic acid (∼41%). The effects of microwave electromagnetic field on the catalysts are discussed.