Kinetics of Methane Oxidation in Shock Waves

The mechanism of methane oxidation in reflected shock waves has been studied by measuring the induction period of the OH absorption and that of the pressure increase simultaneously, and also by using the single-pulse technique combined with gas chromatography. As a result, it has been found under the present experimental conditions that the rate-determining step for the over-all reaction of the methane-rich mixtures with the ratio [CH4]/[O2]=6 is CH4 + O2→ CH3 + HO2, and that the rate-determining step for the over-all reaction of the methane-lean mixtures with the ratio [CH4]/[O2]=3/ 7 is CH2O + O2→ HCO + HO2. Also, the rate-determining step for the OH formation of the lean mixtures has been found to be CH3 + O2→ CH2O + OH under the present conditions. In the case of the intermediate mixtures with the ratio [CH4]/[O2]=1.5, the over-all reaction is considered to be controlled mainly by the reaction CH4 + O2→ CH3 + HO2.