Oxidative Desulfurization of Fuel Oil with Hydrogen Peroxide Catalyzed by Keggin-type Polyoxotungstate in a DC Magnetic Field

Abstract

The oxidation of sulfur-containing compounds was conducted in a DC magnetic field-assisted system, composed of model compound or diesel, 30 wt% hydrogen peroxide, and an iron mono-substituted Keggin-type heteropolytungstate [(C₄H₉)₄N]₄ [PW₁₁Fe(H₂O)O₃₉] catalyst. By combining oxidative desulfurization (ODS) in a magnetic field and acetonitrile extraction, when magnetic field intensity was at 17.3 mT, the removal efficiency of the model compound dibenzothiophene (DBT) in petroleum ether with 1,000 ppm S can reach 98% at 70°C within 30 min with O/S ratio = 3 and catalyst dosage 5%, with 2% increase over that without magnetic field assistance. Under the same reaction conditions, the sulfur level of diesel oil was reduced from 5,647 to 508 ppm. This shows that the DC magnetic field facilitates the oxidation of sulfur-bearing compounds, which allowed greater sulfur removal efficiency under milder reaction conditions.