Precisely regulating the acidity of mesoporous silica on the catalytic performance of 1-decene oligomerization

Abstract

Significant progresses have been made in the performance of homogeneous catalysts in the oligomerization of 1-decene to polyalphaolefin (PAO), whereas it remains a big challenge to design heterogeneous catalysts with high catalytic activity in the PAO synthesis. Herein, a series of heterogeneous mesoporous catalysts with different acidity were successfully synthesized by the in situ incorporation of Al in the channels of mesoporous silica under room temperature and atmospheric pressure. These samples were characterized by various techniques including XRD (X-ray diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), BET (N₂ adsorption–desorption analyses), Py-IR (pyridine-adsorbed IR) and XPS (X-ray photoelectron spectroscopy). The obtained samples exhibit a high surface area, high ordering, and controllable Brønsted and Lewis acid sites. The results indicated that the increasing acidity promotes oligomer selectivity, especially for the trimer (C₃₀). The resulting heterogeneous catalyst exhibited excellent performance with high conversion (70.7%) and high oligomer selectivity (96.7%) due to the suitable acid sites. Moreover, the spent heterogeneous catalyst could be regenerated and its catalytic activity maintained after five cycles.