Reactions of propane on supported Mo2C catalysts

The adsorption and reactions of propane over Mo2C deposited on ZSM-5 and SiO2 have been investigated. Propane adsorbed weakly and nondissociatively on Mo2C catalyst at 150-273 K. At higher temperatures, the characteristic vibrations of pi -bonded and di-sigma -bonded propylene and propylidyne were identified by Fourier transform infrared spectroscopy. The dominant reaction of propane over Mo2C/SiO2 at 773-873 K is its dehydrogenation into propylene. At 873 K the selectivity of propylene formation attained a value of 35-50% at a conversion of 35-25%. The reaction pathway of propane was completely different on Mo2C/ZSM-5: in this case the aromatization of propane was the main process. It was shown that Mo2C improved the effect of pure ZSM-5 in this reaction. The positive influence of Mo2C is explained by its high activity toward the dehydrogenation of propane. The effect of Mo2C was also examined on the aromatization of propylene occurring on the acidic sites of ZSM-5, and no inhibition was observed. (C) 2000 Academic Press.