Gas-phase dehydration of glycerol to acrolein catalysed by caesium heteropoly salt

Abstract

Caesium 12-tungstophosphate, Cs2.5H0.5PW12O40 (CsPW), possessing strong Brønsted acid sites is an active catalyst for the dehydration of glycerol to acrolein in the gas-phase process at 275 °C and 1 bar pressure. The initial glycerol conversion amounts to 100% at 98% acrolein selectivity, however, decreases significantly with the time on stream (∼40% after 6 h) due to catalyst coking, without impairing acrolein selectivity. Doping CsPW with platinum group metals (PGM) (0.3-0.5%) together with co-feeding hydrogen improve catalyst stability to deactivation, while maintaining high selectivity to acrolein. The enhancing effect of PGM was found to increase in the order: Ru ∼ Pt