Kinetic calculation on the hydrogen abstraction reaction between CH_3 radical and CH_3NH_2

Hydrogen abstraction reaction between CH3 radical and CH3NH2 is explored using the QCISD(T)/6-311++G(d,p)//MP2(full)/6-311G(d,p) method.This reaction takes place through two channels: CH3 abstraction from methyl group(CH3)(R1) and amido group(NH2)(R2).The potential barrier of R1,about 3.42 kJ/mol,is lower than that of R2,which shows that two reaction channels will compete mutually.On the basis of the ab initio data,the rate constants for each channel were evaluated using canonical variational transition state theory(CVT) with the small-curvature tunneling correction(SCT) method over a wide temperature range of 200～2 000 K.The total rate constants are excellent to agree with the experimental values.The kinetic calculation indicates that the variational effect on the calculation of rate constants is small over the whole temperature range and the tunneling correction plays an important role in the lower temperature range for all the channels.