An Environmental Friendly Oxidation of Styrene by Anhydrous Hydrogen Peroxide on γ-alumina-supported VxOy Nanoparticle Catalysts with the Adsorption of Reaction Water by Anhydrous MgSO4: Optimization Studies Using RSM

Abstract

In this work, the oxidation of styrene by anhydrous hydrogen peroxide as an environmental friendly oxidant on γ-aluminasupported VxOy nanoparticles catalysts was performed with the continuous adsorption of water by anhydrous MgSO4. This catalyst, with a surface area of 174 m2/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 MgSO4. Response surface methodology (RSM) was employed to examine the effect of anhydrous H2O2 concentration (from 20 to 80mmol), reaction time (from 2.5 to 6h), temperature (from 45 to 90°C), amount of anhydrous MgSO4 (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°C, a reaction time of 4.9h, a H2O2/styrene/anhydrous MgSO4 molar ratio of 2.7:1:1.08 and a catalyst concentration of 0.024g/ml. Keywords: Nanocatalyst, oxidation, sol-gel, γ-alumina, benzaldehyde, RSM, Styrene