Ionic Liquid-based Extraction of Sulfur Compounds From Gasoline as a Complementary Process to Oxidative Desulfurization

The extractive desulfurization of a model and several real gasoline samples was investigated using imidazolium-based ionic liquids (ILs). Factorial design of experiments indicated that, among several process variables, the number of extraction steps and the IL/gasoline volume ratio were statistically highly significant. The results showed a desulfurization efficiency of 95.2% under the optimal conditions. The following order was observed for the extraction of thiophenic compounds: benzothiophene>thiophene>3-methylthiophene>2-methylthiophene, with 96.1% removal efficiency for the first one. The IL extraction was applied as a complementary process for the oxidative desulfurization by hydrogen peroxide and formic acid, which provided high efficiency and selectivity for desulfurization of gasoline.