Bifunctional pyridinium-based Brønsted acidic porous ionic liquid for deep oxidative desulfurization

Porous ionic liquids have been highlighted with special interest for their desirable catalytic activity and extraction properties. Herein, bifunctional porous ionic liquids (denoted UiO-66-BAPILs) were synthesized by dispersing UiO-66 into a pyridinium-based Br & oslash;nsted acidic ionic liquid ([BSPy][CF3SO3]) for oxidative desulfurization. The permanent cavity of UiO-66 moiety in UiO-66-BAPILs was validated as well-preserved by the SO2 uptake experiments and molecular size simulations. Under the optimum reaction conditions, the sulfur removal could reach up to 99.5% with hydrogen peroxide as the oxidant. Additionally, bifunctional UiO-66-BAPILs were deemed as both extractants and catalysts during the reaction. A possible mechanism has been proposed that UiO66-BAPILs extract the aromatic sulfur compounds via pi...pi interactions and C-H...pi interactions and meanwhile oxidize them with peroxysulfonic acids and center dot OH radicals. These findings will open up new avenues to facilitate the catalytic oxidation performance by constructing bifunctional Br & oslash;nsted acidic porous ionic liquids.