CuNiP2O7/CuFe2O4 as Magnetically Separable Solid Acid Nanocatalyst for Synthesis of 1-Amidoalkyl-2-naphthols

Abstract

There is increasing interest in the environmentally friendly synthesis of nanoparticles. In this regard, we report a green method to prepare a novel metal diphosphate nanocatalyst, CuNiP2O7, using ginger extract as a stabilizing agent. The nanocatalyst was further decorated with CuFe2O4 to obtain a magnetically separable nanocatalyst. Characterization was performed using XRD, FESEM, EDX, FTIR, and Raman analyses. The FESEM image clearly reveals the effectiveness of the ginger extract in synthesizing uniformly sized nanoparticles. FT-IR and Raman spectroscopy confirmed the formation of metal-phosphate bonds acting as strong acid sites. The nanocatalyst efficiently facilitated the three-component synthesis of 1-amidoalkyl-2-naphthol under solvent-free conditions, with the best results obtained at an optimized temperature of 90 °C and a reaction time of only 10 min. The optimum amount of the nanocatalyst was found to be 0.04 g, leading to a high yield of 97%. The reusability of the nanocatalyst was confirmed through five successive reaction cycles without significant loss of activity. Various derivatives of amidoalkyl-2-naphthol were successfully synthesized using the prepared nanocatalyst.