Exceptional functionalized dual-acidic ionic liquid: High-efficiency catalytic reaction medium for oxidation desulfurization

The development of highly active functionalized ionic liquids (ILs) as both extractants and catalysts for use in achieving deep desulfurization continues to pose challenges. In this study, a highly efficient oxidative desulfurization system was constructed, composed of dual-acidic ionic liquids (DILs) and H 2 O 2 -AcOH. The investigation results of four DILs prepared from different metal chlorides ([HSO 3 C 3 NEt 3 ]Cl-MnCl n , MnCl n = AlCl 3 , ZnCl 2 , CuCl 2 , FeCl 3 ) in oxidative desulfurization showed that [HSO 3 C 3 NEt 3 ]Cl-AlCl 3 had an outstanding catalytic effect and significantly promoted the oxidation of sulfides. With a 0.2 g [HSO 3 C 3 NEt 3 ]Cl-AlCl 3 , the removal rate of dibenzothiophene (DBT) reached 100% in 10 mL model oil under mild conditions at 55 °C for 20 min. The key is its ability to induce the dismutation of superoxide anions (•O 2 − ), which facilitates the generation of singlet oxygen ( 1 O 2 ). The efficient oxidation of DBT is accomplished through a predominantly 1 O 2 -mediated non-radical mechanism. [HSO 3 C 3 NEt 3 ]Cl-AlCl 3 serves as a favorable medium for contact to be made between 1 O 2 and sulfides, which indicates an efficient catalytic-adsorption synergy.