Magnetic CuNi Alloy Nanoparticles for Catalytic Transfer Hydrogenation of Nitroarene

Magnetic CuNi alloy nanoparticles (CuNi NPs) for the catalytic transfer hydrogenation (CTH) of nitroarene were successfully prepared by the facile thermal decomposition of copper formate (Cuf) and nickel formate (Nif) simultaneously. Liquid paraffin served as solvent, and oleylamine (OAM) acted as both complexing agent and stabilizer. The particle size and Cu/Ni composition of CuNi NPs could be controlled by adjusting the amount of OAM and the Cu/Ni ratio of the precursor. The average diameter of the prepared CuNi NPs ranged from 10.2 to 56.9 nm. It had been confirmed that CuNi NPs were an alloy of Cu and Ni and effectively resistant to oxidation. The prepared CuNi NPs could be separated under an external magnetic field without any energy consumption since they were superparamagnetic. Among the prepared CuNi NPs with different compositions, the Cu3Ni7 NPs were the best catalyst for catalytic transfer hydrogenation of nitrobenzene with ethylene glycol (EG) as the hydrogen donor, giving a nitrobenzene conversion of 99% and an aniline yield of >97%. The conversion and yield remained above 95% and 80% respectively after 10 cycles of NOBF4-treated Cu3Ni7 NPs, demonstrating good reusability for the CTH reaction. This work reported a novel method for preparing magnetic CuNi NPs and also provided a new approach for the hydrogenation of nitroarene catalyzed by non-noble metals in a green environment.