Kinetics of the Reactions of Methyl Radical with Hydrogen, Methyl and Ethyl Peroxides

The HOOH+CH3, CH3OOH+CH3 and CH3CH2OOH+CH3 reactions were characterized using accurate ab initio methods with reliable basis sets. The reaction rate constants were calculated by canonical variational transition state theory as applied to a complex mechanism involving the formation of reactant complexes. The formation of aldehyde or formaldehyde was observed when the CH3 radical attacks on the CH2 group in CH3CH2OOH or on the CH3 group in CH3OOH. The results showed that the channels of H-abstraction from OH group are dominant channels at low temperature, while the channels of OH-transfer to CH3 become predominant with increasing temperature. For the CH3OOH+CH3 reaction, the channel producing CH2O+OH and the OH-transfer channel have a similar rate coefficient.