Deep Extractive Desulfurization of Gasoline with xEt₃NHCl·FeCl₃ Ionic Liquids

x Et 3 NHCl·FeCl 3 ( x = 1.4−1.8) ionic liquids were synthesized by mixing Et 3 NHCl and anhydrous FeCl 3 at 80 °C. These were liquid at room temperature, with low viscosities, and exhibited remarkable abilities in effective desulfurization of thiophene in n -octane and fluid catalytic cracking (FCC) gasoline. Among them, 1.6Et 3 NHCl·FeCl 3 showed the highest sulfur removal. The anionic species FeCl 4 − existed in 1.6Et 3 NHCl·FeCl 3 ionic liquid, as detected by electrospray ionization−mass spectrometry (ESI−MS), and the ionic liquid was stable in air and moisture. Sulfur-free (<10 mg/L) gasoline could be obtained after extraction twice using an ionic liquid/oil volume ratio of 1. The ionic liquid could be recycled 10 times by distillation with a slight decrease in activity.