The effects of reaction pressures on the production of methanol through the selective oxidation of methane in CH4–O2–NOx (x=1 or 2) Original Research Article

The effects of reaction pressures on the selective formation of methanol in a gas phase selective oxidation of CH4 with NOx (x=1 or 2) were examined. Methane conversion was enhanced by the addition of a small amount of NOx (0.125–1.50% ) in a feed gas and also enhanced by raising reaction pressures. The transition barrier of hydrogen abstraction from methane with NO2, i.e. CH4+NO2→CH3radical dot+H–NO2 was lower than that with O2, and the number of these reactions between CH4 and NO2 in a higher pressure reactor was increased. A lower reaction temperature was favorable to enhance the selectivity of CH3OH, and a shorter mean free path in a higher-pressure reactor simultaneously increased the subsequential oxidation of CH3OH. The optimum pressure for the production of methanol at 4% conversion of CH4 was 1.0 MPa for the selective oxidation of methane with 0.50% NO.