Kinetics, mechanism and thermodynamics of reactions of CH₃NHNH₂ with OOH

Abstract

Reactions between CH 3 NHNH 2 and OOH radical were studied using computational methods. The activation energies (E a ) and Gibbs free energies of activation ( G # ) were calculated at the MP2 and B3LYP levels of theory. The calculated activation energies of the hydrogen abstraction reactions were less than 100 kJ/mol and those for the substitution reactions were about 150-250 kJ/mol. The calculated activation energies for the intra-molecular hydrogen transfer reactions in CH 3 NHNH, CH 2 NNH 2 and CH 3 NN molecules were 210-250 kJ/mol. Catalytic effect of the water molecule on the intra-molecular hydrogen transfer reactions was studied. It was found that the water molecule decreases the activation energies by about 70-100 kJ/mol. Rate constants of the reactions were calculated using transition state theory in the temperature range of 298-2000 K. Consecutive hydrogen abstraction reactions from CH 3 NHNH 2 led to the formation of CH 2 NN, which was a very stable molecule.