Oxidative Coupling of CH4 over Molybdates: Catalyst Performance and Characterization

Article abstract of DOI:10.1021/j100182a060

To effect oxidative coupling of methane, a variety of molybdates were used as catalysts with sustained activity for more than 280h.The reaction was studied by cofeeding methane and oxygen at atmospheric pressure, through continuous conventional flow reactors containing the catalyst.The effects of operating conditions were studied and the optimum reactor temperature to achieve high yields of ethane and ethylene was ca. 700-780 deg C, depending on the reactor dimensions.The influence of reactor dimensions on the distribution of products is also reported.Molybdate catalysts are active and yet resistant to deactivation and sintering.Selectivities X(C₂)percent and yields Y(C₂)percent up to 20.0 and 7.0percent were observed, respectively.The reactor feed had a CH4 to O2 ratio of ca. 1.1.Our results present the effects of varying several operating conditions and the significant gas-phase products observed were H2, C2H4, C2H6, C3H6, H2O, and traces of HCHO and CH3OH.C2H2 formation was not observed.The main oxidation products were CO2 and CO.Structural characterization of the molybdates was carried out by elemental analysis, infrared spectroscopy (IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS).