Catalysts Based on Immobilized Ionic Liquids with Bronsted Acid Sites in the Oxidation of Dibenzothiophene

Immobilized ionic liquids with Bronsted acidity containing fragments of nicotinic and phosphomolybdic acids are synthesized by two methods: suspension impregnation and chemical immobilization. The obtained catalysts are characterized by the low-temperature adsorption/desorption of nitrogen, elemental analysis, and transmission electron microscopy. The conditions for exhaustive oxidation of dibeznothiophene are determined: 30 min, the molar ratio of hydrogen peroxide and dibenzothiophene = 6 : 1, the weight fraction of catalyst = 0.5 wt %, and T = 80 degrees C. The catalysts obtained by impregnation lose their activity after regeneration and the catalysts obtained by chemical immobilization retain their activity after at least five oxidation/regeneration cycles.