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

Catalytic gas-phase dehydration of glycerol to produce acrolein was investigated at 315 degrees 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/ZrO2 catalysts showed that the nature of support materials had a significant effect on the thermal stability of HPW; after thermal treatment at 650 degrees 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/ZrO2 catalysts 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/ZrO2 catalysts can be as high as 70 mol% and 54%, respectively, even after 10 h reaction.