An Environmental Friendly Oxidation of Styrene by Anhydrous Hydrogen Peroxide on γ-alumina-supported V_xO_y Nanoparticle Catalysts with the Adsorption of Reaction Water by Anhydrous MgSO_4: Optimization Studies Using RSM

摘要

In this work, the oxidation of styrene by anhydrous hydrogen peroxide as an environmental friendly oxidant on y-alumina-supported V_xO_y nanoparticles catalysts was performed with the continuous adsorption of water by anhydrous MgSO_4. This catalyst, with a surface area of 174 m~2/g, showed good selectivity for benzaldehyde. Poor styrene conversion and benzaldehyde selectivity due to the presence of water can be enhanced by the addition of a water scavenger such as MgSO_4. Response surface methodology (RSM) was employed to examine the effect of anhydrous H_2O_2 concentration (from 20 to 80mmol), reaction time (from 2.5 to 6h), temperature (from 45 to 90℃), amount of anhydrous MgSO_4 (from 8 to 33mmol) and catalyst concentration (from 0.014 to 0.036 g/ml) on the conversion of styrene and the selectivity of benzaldehyde and styrene oxide. Based on the RSM analysis, the optimum conditions for obtaining maximum styrene conversion (61.7%) and benzaldehyde selectivity (84.2%) were as follows: a reaction temperature of 63℃, a reaction time of 4.9h, a H_2O_2/styrene/anhydrous MgSO_4 molar ratio of 2.7:1:1.08 and a catalyst concentration of 0.024g/ml.