Propane Oxydehydrogenation to Propylene Over Molybdenum-based Catalysts

Catalytic oxidative dehydrogenation of propane to propylene has received great research interest in recent years. This reaction stands as a promising alternative to steam cracking and catalytic dehydrogenation, although most of the catalysts proposed need further improvements. This work presents results of the propane oxidative dehydrogenation reaction on alumina supported chromium-molybdenum oxides catalysts - CrxMo(1− x) (where x = 0 − 1). The reaction was conducted at atmospheric pressure, 300 − 420 °C and total feed flowrate of 75 cm3/min (20 cm3/min propane, 5 cm3/min oxygen and the balance helium). The catalysts are active for the reaction. Increase in Mo-ions in the catalysts decreased the reducibilities and changed the nature of the lattice oxygen as indicated by TPR and XPS results. The catalysts with lower reducibilities exhibited corresponding increase in the propylene selectivities. Alkali metals (Li, K, Cs) doped Cr gMo2 (alkali/CrMo weight ratio of 0 − 0.175), showed maxima in both propane conversion and propylene yields for the ratio ranges used. One of the catalysts (Cs/CrMo = 0.125) exhibited the best performance (propane conversion is 15.1% and selectivity to propylene is 64.5%) at 420 °C. It holds promise as a catalyst for oxidative dehydrogenation of propane.