Designing of a novel heterogeneous nanocatalyst ZIF-4@HAp for solvent free base catalyzed esterification reaction

Abstract

Herein, ZIF-4@HAp, a novel hydroxyapatite, HAp-based catalyst, was prepared by a conventional stirring method. Various characterization techniques such as FT-IR, PXRD, UV-DRS, HR-TEM, FE-SEM, NMR, XPS, TGA–DTG and BET were carried out to ensure the effective production of the as-synthesized catalyst. The catalyst, ZIF-4@HAp, was found to be an effective heterogeneous catalyst in organic reaction transformation. Esterification reaction was chosen to evaluate the efficacy of the as-synthesized catalyst. The reactions were carried out between different aliphatic and aromatic acids with methanol under solvent free conditions. Various reaction parameters such as the effect of catalyst doses, reaction temperature, and reaction time were examined to achieve optimal conditions with high product yield. The newly fabricated catalyst converted the chosen acids and alcohols to their corresponding esters with a minimum product yield of 90% in 2 h in each reaction. The organic transformation mechanism of the chosen reaction was also investigated in this study. Further, the prepared catalyst was repeatedly utilized to check its stability and recyclability.