Two-path reduction of molecular nitrogen by transition metal hydroxides

The kinetics of the reduction of N₂ to N₂H₄ and NH₃ by Ti^III-Mo^III hydroxide was studied at pH I I and 303-333 K, and the activation energies for these reactions and also for the reaction N₂H₄ 2 NH₃ were determined (29, 70, and 25 kJ mol^– respectively). It was concluded that -90 % of ammonia was formed by the direct reduction of N₂ without intermediate formation of hydrazine. A mechanism of this reaction is suggested, which includes the proton insertion into the N-N bond favored by an enhanced electron density at the nitrogen atoms, according to the data of the quantum-mechanical calculation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1402–1405, June, 1996.