Enhanced catalytic performance of H3PO4/SiO2 by doping WO3 and Ag for the vapor-phase dehydration of 1,2-propanediol to form propanal

Vapor-phase dehydration of 1,2-propanediol to form propanal was performed over H 3 PO 4 /SiO 2 catalyst with Brønsted acid sites, which exhibited a high activity for the formation of propanal , and the successive modification of H 3 PO 4 /SiO 2 by WO 3 and Ag could further improve both the activity and the stability of catalysts. The H 3 PO 4 /SiO 2 catalyst modified by both Ag and WO 3 could provide a propanal selectivity of 94.6% with a complete conversion of 1,2-propanediol in an H 2 flow at 250 °C and a weight hourly space velocity of 2.70 h −1 . Brønsted acid sites were effective for the formation of propanal, and the doping of WO 3 could significantly increase the amount of Brønsted acid sites, resulting in the improvement of catalytic activity. On the other hand, the doping of Ag could protect the Brønsted acid sites and inhibit coke deposition on the catalyst surface in an H 2 atmosphere, leading to the improvement of catalyst stability.