Modified solid superacid S₂O₈^2-/ZrO₂-CoO for oxidative desulfurization of FCC gasoline

A series of solid super acid catalysts, S₂O₈^2-/ZrO₂, S₂O₈^2-/ZrO₂-CuO and S₂O₈^2-/ZrO₂-CoO, were synthesized by coprecipitation impregnation method with zirconium nitrate, copper nitrate and cobalt nitrate as the metal sources and with ammonium persulfate as the impregnation solution. The catalysts were characterized by XRD, FT-IR and NH₃-TPD. The characterization shows that the S₂O₈^2-/ZrO₂-CoO catalyst has the most super acid sites among the three catalysts. S₂O₈^2-/ZrO₂-CoO as the catalyst and hydrogen peroxide as the oxidant were used for oxidative desulfurization of FCC gasoline, and the effects of reaction temperature, catalyst dosage, reaction time and oxidant dosage on the desulfurization of FCC gasoline were studied. The optimal conditions were determined as:FCC gasoline of 15 mL, reaction temperature of 70℃, reaction time of 1.5 h, oxidant dosage of V(H₂O₂):V(oil)=7.5:1, and catalyst dosage of 0.02 g/mL. Moreover, the reaction product was extracted with N, N-dimethylformamide. When the volume ratio of extractant to gasoline is 1:1, the sulfur removal efficiency and recovery of FCC gasoline reach to 85.34% and 94.45%, respectively. The catalyst exhibits a relatively stable catalytic activity.