Statistical Optimization of Liquid Phase Oxidation of Benzyl Alcohol over Efficient Cobalt Promoted Vanadyl Pyrophosphate Catalysts by Box-Behnken Design

Vanadium phosphorus oxides (VPO) has been applied as a heterogeneous catalyst in gas phase oxidation reactions and its application is very limited in liquid phase. In this study a series of cobalt-doped vanadium phosphorus oxides (VPO-Co) catalysts with different loading of Co (0.01-1.0 mol ratio of Co/V) were prepared. Oxidation of benzyl alcohol was studied in the liquid phase over VPO and VPO-Co catalysts, using tert-butylhydroperoxide (TBHP) as an oxidant. These samples were characterized by XRD, SEM and Fouriertransform infrared (FT-IR) techniques. The optimal design of experiments using Box-Behnken method was employed to evaluate the effects of individual process variables (+1, 0, ‌1, levels) such as, reaction temperature (30, 60 and 90 °C), reaction time (30, 255 and 480 min) and molar ratio of Co/V (0, 0.5 and 1) and their optimum values were found to be 89.86 °C, 477.8 min and 0.64 molar ratio Co/V, respectively, to achieve a conversion of 65.44%.