Oxidative desulfurization of gasoline by ionic liquids coupled with extraction by organic solvents

Abstract

In this work, desulfurization of real fluidized catalytic cracking (FCC) gasoline was investigated in dual steps; first in oxidative desulfurization (ODS) using imidazolium and pyrrolidonium based Brønsted acidic ionic liquids (ILs) as solvent and catalyst and hydrogen peroxide as oxidant. In second step, extractive desulfurization took place using organic solvents of furfural, furfural alcohol and ethylene glycol. Variety of factors such as temperature, time, mass ratio of oil/ILs and regeneration and recycling of ILs, multiple-step desulfurization of ILs and organic solvents and solvent/oil ratio were also investigated. The S-content was significantly decreased to ca. 18 ppm from initial S-content of 260 ppm with a total S-removal of ca. 95% in one-step ODS using pyrrolidonium based ILs coupled with five-step extraction desulfurization (EDS) using furfural alcohol as extractant. This work shows that oxidative desulfurization using ionic liquids coupled with extractive desulfurization using organic solvents is a potential method to produce clean gasoline.