Unsaturated Mo in Mo4O4N3 for efficient catalytic transfer hydrogenation of nitrobenzene using stoichiometric hydrazine hydrate

Abstract

Transfer hydrogenation of nitroarenes to the corresponding anilines using hydrazine hydrate and non-noble metal catalysts has already been widely studied. However, the toxicity resulting from excess hydrazine hydrate and the high reaction temperature limit its industrial application. Herein, a novel N-doped molybdenum oxide compound (Mo₄O₄N₃) was in situ prepared from g-C₃N₄ and (NH₄)₆Mo₇O₂₄·4H₂O (AHM). The as-prepared Mo₄O₄N₃ can achieve a 99% yield of aniline using a stoichiometric molar ratio of hydrazine hydrate (–NO₂ : N₂H₄·H₂O = 1 : 1.5) at room temperature for 50 minutes. Mechanistic experiments and characterization techniques indicate that the acidic sites of unsaturated Mo in Mo₄O₄N₃ can efficiently activate N₂H₄ molecules to form active hydrogen species for catalytic transfer hydrogenation of nitroarenes without the generation of hazardous NH₃. Besides, Mo₄O₄N₃ still exhibited excellent catalytic performance for the large-scale reaction without solvent. This work may offer a feasible and efficient strategy for arylamine production.