New Approach to Ultrafast Oxidative Desulfurization in the Presence of Sulfated Alumina-Based Catalysts

Simple and highly efficient catalysts obtained by modifying aluminum oxide with sulfuric acid and molybdenum oxide were applied in the process of oxidative desulfurization of model and real diesel fuels. The sequence of modification of the support strongly influences both the chemical composition and acidity of the catalyst. When establishing the correlation between the acidic properties and the content of molybdenum oxide active species, it was shown that the decisive factor influencing the activity of the catalyst is the number of acid sites responsible for the coordination of sulfur-containing substrates. The catalysts were characterized by XRD, nitrogen adsorption–desorption, SEM, TEM, temperature-programmed desorption of ammonia, and X-ray fluorescence. Under optimal conditions of 1.0 wt % of catalyst, a H2O2/S molar ratio of 4:1, and T = 80 °C, dibenzothiophene was completely oxidized in just 5 min. The 99.9% efficiency of the synthesized S/Mo/Al2O3 catalyst in oxidative desulfurization of the sulfur-rich real diesel fuel (10 100 ppm) in the production of ultralow sulfur diesel was demonstrated in two-step oxidation (5 wt % of catalyst, H2O2/S molar ratio of 2:1, T = 80 °C).