Studies on the Selection of a Catalyst–OxidantSystem for the Energy-Efficient Desulfurization and Denitrogenationof Fuel Oil at Mild Operating Conditions

This study reports the selection of an ideal catalyst–oxidant system for the energy-efficient catalytic oxidative desulfurization (CODS) of dibenzothiophene (DBT) and denitrogenation (CODN) of pyridine over Mn–Co–Mo/Al2O3 and acid-functionalized 1-butyl-3-methyl imidazolium chloride ([Bmim]Cl/ZnCl2) ionic liquid (IL) catalysts using H2O2 and NaClO as oxidants. The NaClO–catalyst system realized 100% CODS/CODN activity within 15 min at 25 °C at comparatively low activation energies of 4.9 and 5.4 kJ/mol for DBT and pyridine, respectively, under optimal conditions of oxidant-to-sulfur ratio of 4, oxidant-to-nitrogen ratio of 8, ionic liquid-to-oil ratio of 1.5/5, and 0.1 g of Mn–Co–Mo/Al2O3 catalyst for 15 mL of model fuel. Both catalytic activity and kinetics results revealed a NaClO–catalyst system with greater efficiency and lesser energy requirements than a H2O2–catalyst system, and hence the former realized enhanced CODS and CODN than the latter. Furthermore, the Mn–Co–Mo/Al2O3 catalyst favored CODS, w...