Role of OH and HO2 radicals in the slow combustion of mixtures of methane, ethane and ethylene

The combustion of methane is facilitated by the addition of ethane. The induction period is reduced and the maximum rate of combustion is increased. This effect is due to the formation of ethylene which in turn forms formaldehyde. Relative rate constants are deduced for the rates of reaction of hydroxyl radicals with methane, ethane and ethylene over the temperature range 461°C to 525°C. Thus, at 500°C hydroxyl radicals react 5 times as fast with ethylene and 10 times as fast with ethane as with methane. Less accurate rate constant ratios are obtained for the reaction of hydroperoxyl radicals with carbon monoxide, ethane and ethylene.