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 < Pd. The catalyst 0.5%Pd/CsPW gives 96% acrolein selectivity at 79% glycerol conversion, with a specific rate of acrolein production of 23 mmol h−1 gcat−1 at 275 °C and 5 h time on stream, exceeding that reported previously for supported heteropoly acids (5–11 mmol h−1 gcat−1 per total catalyst mass). Evidence is presented regarding the nature of acid sites required for the dehydration of glycerol to acrolein, supporting the importance of strong Brønsted sites for this reaction.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.