Gas phase dehydration of glycerol catalyzed by gamma Al2O3 supported V2O5: a statistical approach for simultaneous optimization

Abstract

Selective gas-phase dehydration of glycerol to acrolein over V₂O₅/γ-Al₂O₃ catalysts was investigated. The catalysts with various V₂O₅ loading were facilely synthesized by an impregnation method. The prepared catalysts were characterized by several techniques such as scanning electron microscopy (SEM), temperature-programmed desorption of NH₃ (TPD-NH₃), temperature programmed reduction (H₂-TPR), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) and X-ray diffraction (XRD). The effects of V₂O₅ loading (5–25 wt%), gas hourly space velocity (GHSV) of O₂/N₂ (120–540 h⁻¹) and reaction temperature (250–320 °C) on yield of acrolein were studied by Box–Behnken design. The influence of independent factors and their quadratic interactions were examined by means of the analysis of variance (ANOVA). The present results indicate that temperature has a different effect on the conversion and selectivity of acrolein. The catalyst with 14.80 wt% of V₂O₅ loading, GHSV of 268.60 h⁻¹ and reaction temperature of 286.35 °C produced the maximum yield of acrolein (73.05%). The analysis revealed that the predicted results agree well with experimental data (12.5 wt% loading of V₂O₅ on γ-Al₂O₃, GHSV of the carrier gas = 330 h⁻¹ and reaction temperature of 285 °C with 68.31% yield).