Chelation and calcination promoted preparation of perovskite-structured BiFeO3 nanoparticles: a novel magnetic catalyst for the synthesis of dihydro-2-oxypyrroles

Abstract

Perovskite-structured Bismuth ferrite (BiFeO3) nanoparticles as a novel heterogeneous catalyst were designed by an auto combustion route using a different chelating agent and calcination temperature. The effect of different chelating agents like disaccharide (sucrose), α-hydroxy acid (citric acid, tartaric acid), amide (urea) and calcination (150–750 °C) temperature on structure and the catalytic performance of BiFeO3 have been analyzed. The catalytic performance of BiFeO3 has been increased by modifying its synthesis with the addition of suitable organic compound and calcination. BiFeO3 synthesized without the use of chelating agent gave very poor yield, i.e., 36.89%. The augmented effect of the chelating agent on the catalytic performance of BiFeO3 was obtained in the order of blank 750 °C. The calcination temperature results in augmentation in yield of approximately 30% with model reaction on increasing temperature from 150 to 650 °C. Different calcination temperatures (150–750 °C) have been employed to obtain single phase BiFeO3 nanoparticles. All synthesized BiFeO3 nanoparticles were fully characterized by FT-IR; XRD; VSM; BET; TGA; XPS and Raman spectroscopy. For the very first time ever we have used them as a recyclable magnetic nanocatalyst in the formation of highly substituted dihydro-2-oxypyrrole by using one-pot, three-component reaction of DMAD, aniline and formaldehyde in methanol at room temperature with 63–88% yield. All the synthesized oxypyrroles have been characterized by various spectroscopic techniques.