Highly active and durable WO3/Al2O3 catalysts for gas-phase dehydration of polyols

Abstract

Gas-phase glycerol dehydration over WO₃/Al₂O₃ catalysts was investigated. WO₃ loading on γ-Al₂O₃ significantly affected the yield of acrolein and the catalyst with 20 wt% WO₃ loading showed the highest activity. The WO₃/Al₂O₃ catalyst with 20 wt% WO₃ loading showed higher activity and durability than the other supported WO₃ catalysts and zeolites. The number of Brønsted acid sites and mesopores of the WO₃/Al₂O₃ catalyst did not decrease after the reaction, suggesting that glycerol has continuous access to Brønsted acid sites inside the mesopores of WO₃/Al₂O₃, thereby sustaining a high rate of formation of acrolein. Dehydration under O₂ flow further increased the durability of the WO₃/Al₂O₃ catalyst, enabling the sustainable formation of acrolein. In addition, the WO₃/Al₂O₃ catalyst with 20 wt% WO₃ loading showed high activity for the dehydration of various polyols to afford the corresponding products in high yield.