| Résumé | The self-reactions of 1,1-dialkylhydrazyl radicals at ambient temperatures have been examined by kinetic epr spectroscopy. Dimethyl-, diethyl-, and dibenzylhydrazyls decay rapidly with bimolecular kinetics. The products suggest that the initial reaction is a dimerization but that the resulting tetrazane is unstable and decomposes to amine and nitrogen. Diisopropylhydrazyl and the hydrazyl derived from 1-amino-2,2,6,6-tetramethylpiperidine decay slowly with first-order kinetics. These radicals exist in equilibrium with their dimer. Decay involves a disproportionation reaction of the free radicals with the formation of the parent hydrazine and an N-nitrene. The dialkylaminonitrenes decompose to hydrocarbons and nitrogen. Arrhenius parameters for these decays and the heats of dimerization were determined. The results are discussed both in relation to classical studies of the oxidation of 1,1-dialkylhydrazines and in relation to the decay processes for the isoelectronic alkylperoxy radicals and dialkyl nitroxides. |
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