Phosphotungstic\nAcid-Supported Hercynite: A Magnetic\nNanocomposite Catalyst for the Selective Esterification of Chloroacetic\nAcid

This study presents the synthesis and characterization\nof a novel\nphosphotungstic acid-functionalized hercynite@SiO<sub>2</sub> magnetic\ncore–shell through a three-step procedure. The characterization\ninvolved various analyses including Fourier-transform infrared spectroscopy,\nP-XRD, TGA-DSC, EDAX, inductively coupled plasma optical emission\nspectroscopy, elemental mapping, scanning electron microscopy, transmission\nelectron microscopy, and value stream mapping. The catalytic performance\nof the hercynite@SiO<sub>2</sub>–PTA nanomagnetic composite\nwas examined in the esterification of chloroacetic acid. Results indicate\nthat the developed procedure enables the production of chloroacetic\nacid esters using a wide range of primary, secondary, and tertiary\naliphatic and aromatic alcohols with good to excellent yields and\nhigh selectivity. The significance of this work lies in its straightforward\nsynthesis method, minimal time requirement, reduced utilization of\nhazardous chemicals, and cost-effectiveness. Additionally, the catalyst\nexhibited magnetic recyclability for up to five cycles with negligible\nloss in activity. Notably, the synthesized catalyst demonstrated nontoxicity\nand environmental friendliness.