Deep oxidative desulfurization of dibenzothiophene by novel POM-based IL immobilized on well-ordered KIT-6

Oxidative desulfurization (ODS) process is one of the most promising desulfurization technologies because of its energy-efficient and mild operation condition. In this study, a novel active phase POM-based IL-[Omim]3PMo12O40 was synthesized, and then it was supported on well-ordered KIT-6. [Omim]3PMo12O40/KIT-6 catalyst was used in the dibenzothiophene (DBT) and real diesel oxidative desulfurization with tertbutyl hydroperoxide (TBHP) as an oxidant. The composite materials [Omim]3PMo12O40 and [Omim]3PMo12O40/KIT-6 catalysts were characterized by means of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photo-electron spectroscopy (XPS) and nitrogen adsorption–desorption analysis. [Omim]3PMo12O40/KIT-6 catalyst showed high catalytic activity, at the optimal conditions of mcatalyst/VOil = 0.1 g/20 ml, m[Omim]3PMo12O40/mKIT-6 = 30%, O/S = 5 (molar ratio), 60 °C, S of 1000 ppm (DBT in n-octane) can be completely removed within 80 min due to the superior mass transfer ability of the cubic Ia3_d mesoporous structure of KIT-6 and excellent catalytic ability of [Omim]3PMo12O40. In addition, [Omim]3PMo12O40/KIT-6 could be easily separated and the catalytic activity remains stable after 9 cycles. The ODS reaction mechanism is also investigated.