Green and highly efficient approach for the reductive coupling of nitroarenes to azoxyarenes using the new mesoporous Fe₃O₄@SiO₂@Co–Zr–Sb catalyst

Abstract

Efficient, green, simple and environmentally friendly approach for the straightforward reductive coupling of nitroarenes to the corresponding azoxyarenes has been developed in the presence of Fe₃O₄@SiO₂@Co–Zr–Sb as a novel recyclable nanocatalyst. The Co–Zr–Sb trimetallic nanoparticles immobilized on silica-layered magnetite have been prepared by the co-precipitation method. The mesoporous catalyst has been characterized by FT-IR, SEM, EDX, VSM, TEM and XRD analyses. The chemoselective hydrogenation of nitrobenzenes was carried out successfully in refluxing water to afford the corresponding azoxybenzenes within 2–10 min in good to high yields. The reusability of the heterogeneous nanocatalyst has also been studied using the FT-IR and SEM analyses. The catalyst was utilized four times in sequential runs without significant loss of activity. The current research includes remarkable advantages of short reaction times, absence of hazardous organic solvents, mild reaction conditions, high yields, using water as a green solvent and the ability to utilize the recyclable nanomagnetic catalyst.