Study on the structure-reactivity correlation of SO₄^2-/ZrO₂-Al₂O₃ in n-butane isomerization reaction

A series of alumina-promoted sulfated zirconia catalysts were prepared by precipitation-impregnation method. The catalysts were characterized by N₂ sorption, pyridine adsorption Fourier transform infrared spectroscopy (Py-FTIR), X-ray diffraction (XRD). Their catalytic performance in n-butane isomerization was evaluated in a continuous flow type fixed-bed micro-reactor at atmospheric pressure, 200℃, and H₂:C₄=2:3, with a weight hourly space velocity of n-butane (WHSV) of 3 h^-1. The structure-reactivity relationship between surface acidity and catalytic behavior was revealed. Py-FTIR indicates that the sulfated treatment enhances the strength and density of catalytic Brønsted acid sites, which are essential for n-butane isomerization. Therefore, sulfated treatment can significantly improve the activity of n-butane isomerization, and Lewis acidity has no direct effect on it.