CuO-Fe(III)-Zeolite-Y as efficient catalyst for oxidative alcohol-amine coupling reactions

Abstract

CuO nanocatalyst with layered structure was supported over Fe-exchanged zeolite-Y (CuO-Fe(III)-Y) for selective synthesis of amides by oxidative coupling of aromatic primary alcohols and amines. The CuO-Fe(III)-Y catalyst was characterized by different physicochemical and spectroscopic techniques. The amide bond formation reaction was found to occur in absence of any external base and reagents. The temperature-programmed desorption (TPD) study predicted the development of strong basic sites in the CuO-Fe(III)-Y catalyst that boosted the dehydrogenative coupling process. The activity of the material in such coupling reaction was found to be comparable to those of other costly metal catalysts under different reaction conditions. The product yield of the reaction was found to be substrate-dependent giving moderate to maximum yield of 85%. The anomalies in the reaction appeared in case of 5-nitro-2‑chloro-benzylalcohol that undergoes a C[sbnd]N coupling product through C[sbnd]Cl bond activation. The mechanism of the reaction was believed to proceed through FeIV=O species that helped in the activation of the benzylic C[sbnd]H bond.