Nickel Boride Supported on Graphitic Carbon Nitride as Robust and Efficient Catalyst for Transfer Hydrogenation of Nitroarenes

Abstract

Hydrogenation of nitroarenes to aromatic amines is an essential reaction in chemical synthesis, commonly employed in pharmaceutical and industrial applications. Typically, this transformation employs molecular hydrogen (H₂) as a reducing agent, but its use comes with challenges, such as flammability, handling of high-pressure systems, sophisticated reaction setup, and so on all of which increase the costs and reduces the sustainability for large-scale operations. Catalytic transfer hydrogenation (CTH) presents a facile and simple alternative. Herein, a series of nickel boride (Ni₃B) supported graphitic carbon nitride (GCN) are used as catalysts to convert aromatic nitroarenes to aromatic amines via transfer hydrogenation, using hydrazine hydrate as the hydrogen source. Among a series of different weight percentage of Ni₃B on GCN catalysts, the sample with 25 wt% Ni₃B, shows the highest activity in nitroarene hydrogenation. The reaction conditions are thoroughly optimized by varying various parameters, including temperature, time, catalyst loading, and hydrogen source amount. In addition, the optimized catalyst shows good recyclability and stability for four reaction cycles. These findings indicate that these catalysts offer a promising solution for robust and efficient hydrogenation in organic synthesis, with potential applications in industry.