Mechanisms and kinetics of hydrogen abstraction of methylhydrazine and deuterated methylhydrazine with H/D atoms

The mechanisms of multi-channel reactions (1) CH 3 NHNH 2 + H → products (R1) and (2) (CH 3 ) 2 NNH 2 + H → products (R2) have been investigated, and the dynamic properties are studied by using the dual-level direct dynamics method. The electronic structures and energies of the stationary points are calculated by the combination of various methods and basis sets. The rate constants of reactions are evaluated in a temperature range of 200–2,000 K by using the canonical variational transition state theory with a small-curvature tunneling correction at the MCG3-MPWPW91//MPW1K/6-311G(d,p) level. The effect of treating torsional anharmonicity with different models on the rate constants is compared. Theoretical and experimental studies indicate that substitution of H by –CH 3 group on NH 2 NH 2 leads to a significant rate coefficients increase. The kinetic isotope effects are studied for both the methylhydrazine with hydrogen/deuterium and the methylhydrazine/deuterated methylhydrazine with hydrogen atom.