Magnetically Retrievable CuNi Alloy as Catalyst for Reductive Coupling of Nitroarenes with 2-Propanol

Abstract

Magnetic nanoparticles (NPs) are potentially useful in various areas of catalysis because of their unique physical and chemical properties. Especially, magnetic alloy NPs gain more interest due to their magnetic behavior and chemical stability. Herein, we demonstrate a heterogeneous magnetically retrievable CuNi catalyst system for the reductive coupling of nitroarenes through transfer hydrogenation using 2-propanol as both a solvent and a hydrogen donor. The catalyst was prepared by a modified hydrothermal method without use of any surfactant and structure-directing agent. It exhibited unique catalytic activity for the reductive coupling of various substituted nitroarenes to the corresponding valued-added products with yields >95%. The nitroarenes with electron donating and withdrawing substituents exhibit remarkable activity towards aniline derivatives signifying that these functionalities do not impact on the reaction. Moreover, the prominent magnetic features of the NPs allow easy retrievability from the reaction mixture. It was reused for five consecutive cycles without significant loss in the activity. Thus, magnetic non-noble catalysts tender a new environment friendly approach for the sustainable reductive coupling of nitroarenes with nontoxic 2-propanol.