One-Step Oxidative Desulfurization of Dibenzothiophene Using Cyclohexanone Peroxide in N-Alkyl-imidazolium–Based Ionic Liquid Extraction Systems

Abstract

One-step oxidative desulfurization of dibenzothiophene (DBT) using cyclohexanone peroxide (CYHPO) was performed in the presence of N-alkyl-imidazolium-based ionic liquids (ILs). CYHPO is an oil-soluble oxidant and ILs are employed as extractants. The effect of the ILs, the molar ratio of CYHPO/S (O/S), volume ratio (V_IL/V_{model oil}), reaction time (T), and reaction temperature (t) were investigated in detail. The results showed that the desulfurization ability of the ILs followed the order [OMim]BF₄ > [HMim]BF₄ > [BMim]BF₄, reversing the length of the alkyl group to the imidazolium ring. When IL [OMim]BF₄ was used, O/S was 2 and V_IL/V_{model oil} was 1:1, and 93.5% of DBT in the model oil was removed at 40°C for 30 min. The desulfurization rate of gasoline was 70.8% under optimal conditions. IL ([OMim]BF₄) could be recycled for five times without a significant decrease in activity.

Keywords:

• cyclohexanone peroxide
• dibenzothiophene
• ionic liquid
• one step
• oxidative desulfurization

Notes

^aTen milliliters of model oil with IL ([BMim]BF₄) heated to 40°C for 2 hr.

^bTen milliliters of model oil with CYHPO heated to 40°C for 2 hr.

^cTen milliliters of model oil with CYHPO and IL ([BMim]BF₄) heated to 40°C for 2 hr in two steps.

^dTen milliliters of model oil with CYHPO and IL ([BMim]BF₄) heated to 40°C for 2 hr in one step.