Oxidative desulfurization of thiophene catalyzed by (C4H9)4NBr•2C6H11NO coordinated ionic liquid

Oxidative desulfurization (ODS) of thiophene with hydrogen peroxide/acetic acid using a quaternary ammonium coordinated ionic liquid (IL) (C4H9)(4)NBr center dot 2C(6)H(11)NO as an effective catalyst has been studied. The catalyst of coordinated IL (C4H9)(4)NBr center dot 2C(6)H(11)NO without fluorous anions is environmentally benign and easy prepare from cheap amines. Thiophene can be oxidized in the oil phase to greater polar sulfoxide, sulfone, SO42-. Most of the oxidation products transfer to the water phase for their higher polar property, resulting in the removal of thiophene from the n-octane phase without additional extraction by solvent. The effect of the amount of catalyst, hydrogen peroxide, and acetic acid, reaction time, and temperature were investigated in detail. Optimal amounts of catalyst, hydrogen peroxide, and acetic acid were obtained at amounts near 0.20 g, 2, and 4 mL/18 mL of model oil, respectively. The catalytic oxidative desulfurization, 98.8% removal rate thiophene in n-octane, and 95.3% sulfur removal rate of actual fluidized catalytic cracking (FCC) gasoline were achieved after 30 min under optimal experimental conditions. Kinetics parameters of the catalytic oxidation of thiophene were measured and calculated. The results show that the kinetics of catalytic oxidation of thiophene is pseudo-first-order, with an apparent rate constant of 1.05 x 10(-3) s(-1) and half-life of 660 s.