New magnetic nanocomposites of ZrO2–Al2O3–Fe3O4 as green solid acid catalysts in organic reactions

Abstract

A series of magnetic solid acid nano-catalysts were designed and prepared through a facile co-precipitate approach. The original nanocomposites ZrO₂–Al₂O₃–Fe₃O₄ were characterized by means of ICP-AES, BET, XRD, TEM, HRTEM, VSM, FT-IR, NH₃-TPD and TG. Their catalytic behaviours were investigated via esterification, the synthesis of bis-indolylmethanes, Hantzsch reaction, Biginelli reaction and Pechmann reaction. In all of these organic reactions, the corresponding products were obtained in moderate to excellent yields. The optimal catalyst was ZAF-16/16, which retained catalytic activity after several recycles.