Propane oxidative dehydrogenation on Cs-doped Cr-Mo-Al-O catalyst: kinetics and mechanism

Abstract

Previous kinetic study reports on oxidative dehydrogenation (OXD) have suggested different mechanisms—Mars-van Krevelen (MV), Langmuir–Hinshelwood (L–H) and Rideal—depending on the nature of the catalyst. Earlier, we have demonstrated that Cs-Cr-Mo-Al-O is active and selective as a catalyst in propane oxidative dehydrogenation (POD). Here results of the reaction kinetic study on the catalyst at 300–340 °C are reported. Propane is oxidatively dehydrogenated to propene. Carbon dioxide is also produced directly from propane. Further oxidation of propene produced mainly CO. Rates of propane consumption and propene production are not significantly affected by changes in oxygen partial pressure, indicating a Mars-van Krevelen reaction mechanism. On the other hand, rates of CO 2 and CO productions have shown strong dependence on the partial pressure. Thus, oxygen species of difference types may be involve in the two cases.