A detail kinetic study on vapour phase oxidation of diphenylmethane over mesoporous V-KIT-6 catalyst

Mesoporous V-KIT-6 catalysts with different Si/V ratios of 25,50,75 and 100 were synthesized by hydrothermal method under the controlled acidic conditions and characterized by using low angle XRD, ICP-OES, Diffuse reflectance UV-vis, SEM and TEM analysis. The characterization results are confirmed that most of the vanadium was mainly incorporated in the form of an isolated tetrahedral environment with terminal V=O bond units. The synthesized catalysts were tested for the vapour phase selective oxidation of diphenylmethane (DPM) using air as an oxidant. A detail kinetic study was carried out on V-KIT-6 (25) catalyst using Langmuir-Hinshelwood (LH) model. The combined studies of Langmuir-Hinshelwood (LH) model and transition state theory (TST) explain that the reaction follows a second-order rate expression with respect to surface coverage of DPM and molecular oxygen. The reaction data derived from the LH modeling is allowed us to calculate the true activation energy and activation entropy of the reaction. The nature of transition state was determined from transition state theory and possible reaction mechanism was proposed for this reaction. (C) 2017 Published by Elsevier B.V.