Highly active and durable WO 3 /Al 2 O 3 catalysts for gas-phase dehydration of polyols.

Gas-phase glycerol dehydration over WO 3 /Al 2 O 3 catalysts was investigated. WO 3 loading on γ-Al 2 O 3 significantly affected the yield of acrolein and the catalyst with 20 wt% WO 3 loading showed the highest activity. The WO 3 /Al 2 O 3 catalyst with 20 wt% WO 3 loading showed higher activity and durability than the other supported WO 3 catalysts and zeolites. The number of Brønsted acid sites and mesopores of the WO 3 /Al 2 O 3 catalyst did not decrease after the reaction, suggesting that glycerol has continuous access to Brønsted acid sites inside the mesopores of WO 3 /Al 2 O 3 , thereby sustaining a high rate of formation of acrolein. Dehydration under O 2 flow further increased the durability of the WO 3 /Al 2 O 3 catalyst, enabling the sustainable formation of acrolein. In addition, the WO 3 /Al 2 O 3 catalyst with 20 wt% WO 3 loading showed high activity for the dehydration of various polyols to afford the corresponding products in high yield.