Kinetics of hydrogen and deuterium atom abstraction by methyl radicals from hydrazines and substituted hydrazines

Abstract

The reactions of methyl radicals with seven substituted and deuterated hydrazines have been investigated and values for the velocity constant and Arrhenius parameters of hydrogen abstraction have been obtained. The positions of attack on dimethyl hydrazines, and the size of the kinetic isotope effects in abstraction from N—H bonds, have been derived from experiments using deuterium-substituted compounds. Arrhenius parameters (based on Shepp's value for the combination of methyl radicals) have been determined for the following reactions: [graphic omitted]

Kinetic isotope effects (k_H/k_D, etc.) are substantially in accord with expectations based on zeropoint-energy differences. The general patterns of reactivity are similar to those found in related isoelectronic and homologous compounds.