Hydrodeoxygenation of benzophenone on Pd catalysts

Catalytic hydrogenation and hydrogenolysis of benzophenone in a liquid phase at the reaction temperature of 130 °C and pressure 6 MPa on supported palladium catalysts were investigated. A number of different supports including active carbon, alumina, Beta and ZSM-5 zeolites with different Si/Al ratios and MCM-41 was tested. The effects of solvent, support and its acidity on the course of benzophenone transformations were studied. Catalysts using acid zeolite or active carbon as supports were found very effective in hydrodeoxygenation reaction. Based on the kinetic model applied, possibilities of conversion of benzophenone to diphenylmethane were discussed. The model confirmed that both the possible mechanisms (the hydrogenation-hydrogenolytic and the direct hydrogenolysis of the CO bond of benzophenone) took place in a significant manner.