The Research on the Esterification Deacidification of Vacuum Gas Oil by FeZn Bimetal–Organic Frameworks Catalysts

The FeZn-MOFs@Al₂O₃ catalyst was synthesized under solvothermal conditions. Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), temperature-programmed desorption of ammonia (NH₃-TPD), and specific Brunauer-Emmett-Teller (BET) surface area and pore volume were used to systematically investigate the effects of different parameters such as molar ratio of iron to zinc, synthesis temperature, and synthesis time on the properties of the materials. The results showed that the optimum synthesis conditions of FeZn-MOFs@Al₂O₃ composites were 140 °C for 1 h, and the optimum molar ratio of Fe³⁺ and Zn²⁺ was 1.3:0.7. Under the aforesaid conditions, FeZn-MOFs@Al₂O₃ had the deacidification rate of vacuum gas oil (VGO) up to 96.3%. The optimum esterification parameters were as follows: the amounts of catalyst and ethylene glycol were, respectively, 2.5 wt% and 4.0 wt% of the sample oil, the reaction temperature was 250 °C, and the reaction time was 1 h.