Gasoline desulfurization using extraction with [C8mim][BF4] ionic liquid



Increased reductions of statutory sulfur content on fossil fuels as gasoline or diesel have led to intense research into all possible methods of desulfurization. With the aim to study [C8mim][BF4] ionic liquid as extraction solvent for desulfurization, the phase equilibria of different ternary systems involving hydrocarbons present in gasoline formulations, thiophene, and [C8mim][BF4], were obtained experimentally. Potential interest of this ionic liquid for desulfurization was confirmed by the phase equilibria determined. As design of a multistage separation process requires knowledge of phase equilibria, simultaneous correlation of liquid–liquid equilibrium data was done using the nonrandom two liquid (NRTL) activity coefficient model. A gasoline formulation was simulated as a mixture of n-hexane, cyclohexane, iso-octane, and toluene with thiophene and dibezothiophene as sulfur-components, and its desulfurization was performed by multistage extraction using the ionic liquid in three successive stages. © 2007 American Institute of Chemical Engineers AIChE J, 2007