The influence of Si/V ratio of mesoporous V-SBA-15 on the structure and catalytic behavior has been investigated for the vapor phase oxidation of diphenylmethane (DPM) to benzophenone (BP) using CO2 free air as oxidant under atmospheric pressure. The reaction conditions were optimized for a maximum conversion of DPM and selectivity for BP on V-SBA-15 (25). These catalysts were synthesized with different Si/V ratios of 10, 25, 50, 75 and 100 by the direct hydrothermal method under mild acidic conditions and characterized by using X-ray diffraction, ICP-OES, EDAX, DRUV–Vis, photoluminescence and transmission electron microscopy techniques. It was found that a large amount of vanadium is incorporated mainly in isolated tetrahedral environment with a terminal V=O bond. Under the optimized conditions, the activity of all the catalysts were compared and found that V-SBA-15 with Si/V = 25 ratio, exhibited the maximum activity. The difference in the catalytic activity is related to their physico-chemical properties.
Graham Hutchings, J, Michael Scurrell, S (2003) Cattech. 7:90.