Partial oxidation of CH4 to HCHO over a MoO3-SiO2 catalyst: A kinetic study



There is considerable economic incentive to convert methane into formaldehyde, which is used in the manufacture of insulating materials and adhesives. This paper discusses the kinetics of a one-step oxidation of methane with molecular oxygen over a MoO3-SiO2 catalyst. The space velocity was varied between 2,500 and 10,000 h−1 (at NTP) over a range of temperatures from 848 to 923 K.

Selectivities to formaldehyde between 30 and 89% were observed in the 0–5% methane conversion range, the other principal products being CO, CO2, and H2O. Kinetic analysis indicates that methane is directly oxidized to CO2 and HCHO, with HCHO being further oxidized to CO. The reactions were all found to be zero order in oxygen concentration, with methane and formaldehyde oxidation following overall first-order rate laws. Kinetic rate constants have been determined and there is good agreement between model predictions and experimental data.