Oxidative desulfurization of diesel fuel using a Brønsted acid room temperature ionic liquid in the presence of H2O2

The Brønsted acid ionic liquid N-methyl-pyrrolidoniumtetrafluoroborate ([Hnmp]BF4) was utilized as the extractant and catalyst for extraction/oxidative desulfurization (ODS) of model oil and diesel fuel in the presence of H2O2 by a combination of both chemical oxidation and solvent extraction. A coordination compound was generated between hydrogen peroxide and the cation of the ionic liquid, and the hydrogen peroxide on the coordination compound decomposed to produce hydroxyl radicals. The sulfur-containing compounds in model oil or diesel fuel were extracted into the ionic liquid phase and oxidized to their corresponding sulfones by the hydroxyl radicals. The room temperature ionic liquid [Hnmp]BF4 can be recycled 7 times without a significant decrease in desulfurization.