Sustainable production of acrolein: gas-phase dehydration of glycerol over 12-tungstophosphoric acid supported on ZrO2 and SiO2

Abstract

Catalytic gas-phase dehydration of glycerol to produce acrolein was investigated at 315 °C over ZrO₂- and SiO₂-supported 12-tungstophosphoric acid (H₃PW₁₂O₄₀, HPW) catalysts with different treatment temperatures. Characterizations with XRD and Raman spectroscopy of the prepared HPW/SiO₂, HPW/ZrO₂catalysts showed that the nature of support materials had a significant effect on the thermal stability of HPW; after thermal treatment at 650 °C, the Keggin structure of HPW remained intact on the surface of ZrO₂ but was completely destroyed on SiO₂. HPW on ZrO₂ also showed higher dispersion than on SiO₂. In comparison to HPW/SiO₂, HPW/ZrO₂catalysts exhibited significantly higher activity and selectivity for the formation of acrolein, as well as a slower deactivation rate during the dehydration reaction. The selectivity and yield for acrolein over the better HPW/ZrO₂catalysts can be as high as 70 mol% and 54%, respectively, even after 10 h reaction.