Liquid phase propylene epoxidation with H2O2 on TS-1/SiO2 catalyst in a fixed-bed reactor: experiments and deactivation kinetics

BACKGROUNDThe epoxidation of propylene with H2O2 in liquid phase catalyzed by a TS-1/SiO2 catalyst in a fixed-bed reactor has been studied. The effects of reaction temperature (313-328 K), methanol concentrations (55-70 wt%) and hydrogen peroxide concentrations (9-15 wt%) on the reaction are investigated. The fresh, deactivated and regenerated catalysts were characterized with XRD, FT-IR, UV-vis, N-2 sorption and TG to study the reasons for catalyst deactivation. In addition, the kinetics of catalyst deactivation was studied by fitting the experimental data. RESULTSThe rate of decrease of H2O2 conversion decreases with increasing reaction temperature and methanol concentration, but increases with increasing hydrogen peroxide concentration. The reason for catalyst deactivation is that the bulky organic matter covers the active centers. The study on deactivation kinetics shows that the deactivation reaction order is 2, and an expression for H2O2 conversion as a function of reaction time is obtained. CONCLUSIONThe operating conditions such as reaction temperature, methanol concentration and hydrogen peroxide concentration remarkably affect the reaction. The kinetic parameters including deactivation reaction order and activation energy are developed by fitting the experimental data based on the Wojciechowski model. (c) 2014 Society of Chemical Industry