Nanomagnetic zirconia-based sulfonic acid (Fe3O4@ZrO2-Pr-SO3H): a new, efficient and recyclable solid acid catalyst for the protection of alcohols via HMDS under solvent free conditions

Abstract

In the present work, sulfonic acid functionalized nanomagnetic zirconia is prepared by the reaction of (3-mercaptopropyl)trimethoxysilane and nanomagnetic zirconia. Then, nanomagnetic zirconia-based sulfonic acid (Fe₃O₄@ZrO₂-Pr-SO₃H) is synthesized through direct oxidation of the thiol group by hydrogen peroxide and H₂SO₄ subsequently. The catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) imaging, energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) measurements and vibrational sample magnetometry (VSM). It was used as an effective nanocatalyst with high catalytic activity for the protection of alcohols using hexamethyldisilazane (HMDS) under solvent-free conditions at room temperature. The solid nanocatalyst can easily be separated and reused several times without significant loss of its catalytic activity. Also, in addition to its being inexpensive and the simplicity of the separation process, this heterogeneous catalyst has shown a good chemoselectivity in the reactions.