Copper sulphate immobilized on P(AN-NIPAM-MBAM) terpolymer as a highly efficient catalyst for the selective reduction of nitro-arenes

Abstract

A new copper sulphate anchored to an acrylonitrile-N-isopropylacrylamide-bisacrylamide based P(AN-NIPAM-MBAM) terpolymer support has been employed as a catalyst for the hydrogenation of varied substituted nitro-arenes affording corresponding amines with excellent yield. Application of hydrogen source from NaBH₄ in combination with NaOH under water and/or methanol solvent system at 50-55°C has been investigated. The terpolymer and catalyst have been characterized by ICP-OES, FT-IR, TGA, SEM and EDAX analysis methods. Different parameters supporting chemo-selective hydrogenation such as concentration of NaBH₄, TP-CuSO₄, assisting base and solvents have been investigated. Controllable vigorous H₂ gas evolution, low-temperature requirement, feasibility under air atmosphere, low catalyst loading, use of non-toxic reagents and solvents, high isolated yield, easy work-up procedure, purification without involving tedious column or flash chromatographic separation techniques, makes this protocol highly significant from the implementation point of view.