Fe₃O₄@SiO₂-SO₃H nanocomposites were successfully synthesised as the efficient magnetically separable solid acid catalysts for an esterification reaction. The resultant catalysts were characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, vibrating sample magnetometer (VSM), and nitrogen physical adsorption analyses [Brunauer–Emmett–Teller (BET) theory]. The catalytic activities of as-prepared Fe₃O₄@SiO₂-SO₃H nanocomposites were also investigated for the esterification of n-butyl acetate and isoamyl acetate. The acid esterification rate was confirmed by gas chromatography. The results showed that the Fe₃O₄@SiO₂-SO₃H nanocomposites can be as candidate cataysts for the concentrated H₂SO₄ for the esterification reaction of n-butyl alcohol or isoamyl alcohol. More importantly, the magnetic catalysts can be easily separated from the reaction system by a magnetic bar and reused at least three recycles without significant degradation of their activities.

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Fe₃O₄@SiO₂-SO₃H nanocomposites: an efficient magnetically separable solid acid catalysts for esterification reaction

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Fe₃O₄@SiO₂-SO₃H nanocomposites: an efficient magnetically separable solid acid catalysts for esterification reaction