Waste-Derived Iron Nanoparticles for Solvent-Free Single-Step Reductive Acetylation of Nitroarenes

Abstract

A simple and single-step synthetic protocol is reported here for synthesizing medicinally important amide compounds such as acetanilide (N-phenylacetamide) and its derivatives (including paracetamol and phenacetin). Compared to the existing reports used for a single-step amidation that requires multiple reagents, herein, waste-derived iron nanoparticles (FeOx-NPs) isolated from the “free-of-cost available iron dust/powder” were used for the same single-step amidation reaction without using any external reagents and high pressure, resulting in the cost-effective viable reported procedure. The Soxhlet-purified iron dust is subjected to high-temperature heating at ∼800 °C in a muffle furnace to achieve its heterogeneously active form (Fe3O4-type moieties on its surface). The as-prepared catalyst (FeOx-NPs) has been used to synthesize 17 acetanilide derivatives including two essential antipyretic drugs, paracetamol and phenacetin, on a gram scale, and one industrially important dye/pigment precursor (2-nitroacetanilide). Based on the X-ray photoelectron spectroscopy and vibrating sample magnetometry results, a possible mechanism has been proposed. The sustainability associated with the whole process is the direct amide formation using a magnetically separable waste-derived metal catalyst in solvent-free conditions, which provides a possible way to utilize large-scale industrial waste, thus directly reducing some environmental stress.