Catalytic aerobic desulfurization of fuels in the presence of nanosized mixed carbide FeWC

Nanosized mixed tungsten-iron carbide (FeWC) was successfully applied in aerobic oxidative desulfurization. The combination of catalytically active centers responsible for the activation of oxygen and the oxidation of sulfur-containing compounds made it possible to obtain a highly efficient catalyst. The catalyst was synthesized by microwave irradiation, allowing to obtain a nanoscale catalyst in just 15 min. The catalyst was characterized in detail by a variety of methods: XRD, HRTEM, EDX, SEM, XPS, and low-temperature nitrogen adsorption/ desorption. The key factors influencing the dibenzothiophene (DBT) oxidation were investigated. Under opti-mized conditions DBT conversion was 100% in 1 h at 130 degrees C, 6 atm. The possible mechanisms including oxygen activation, alkyl peroxide formation, and substrate oxidation by tungsten peroxo-complexes were discussed. The catalyst retains its activity for at least 5 cycles of oxidation-regeneration. Aerobic oxidative desulfurization of straight-run gasoline in the presence of FeWC was performed and sulfur content was reduced from 995 to 6 ppm.