Catalytic oxidative desulfurization of benzothiophene using silica-supported heteropolyacid catalyst: activity, deactivation and regeneration of the catalyst

摘要

A series of silica-supported heteropolyacid catalysts were prepared by the hydrothermal dispersion and ultrasonic impregnation methods, using phosphotungstic acid as active component and HMS molecular sieve as support. The catalytic stability of catalysts in the oxidative desulfurization of benzothiophene has been investigated. The results show that the sulfur removal of the two catalysts decreased from 97.81 and 95.63 to 81.28 and 75.3 % after eight cycles. The fresh and spent catalysts were characterized by Fourier transform infrared spectra, N-2 adsorption, X-ray diffraction and transmission electron microscopy. The main results indicate that the deactivation process of the catalysts went through two stages, i.e., the dissolution of active component is the main factor at prophase and the adsorption of N-hexadecane and sulfone is the primary reason at anaphase. Furthermore, the former is an irreversible deactivation and the latter is a reversible deactivation which can be regenerated by solvent extraction.