The effect of heteropolyacid-based ionic liquid catalysts for oxidative desulfurization of fuel

Oxidative desulfurization technology is of interest due to its high efficiency in sulfur removal and mild conditions. The aim of this study is to synthesize a heteropolyacid-based ionic liquids for the removal of benzothiophene compound from model fuel under relatively mild conditions with high efficiency. The catalysts were characterized by FT-IR, ¹H-NMR, ¹³C-NMR, TGA, EDX. Among the studied catalysts, [CMDMAPy]₃PW₁₂O₄₀ emerged as the most effective catalyst. With optimized catalyst for the removal of less active BT, using 0.04 g of catalyst, O/S ratio of 8, temperature of 70 °C and 1.5 mL of CH₃CN, removal of 99% of benzothiophene was achieved within 2.5 h. The catalyst exhibits good amphiphilic activity. Which can be attributed to active sites. The reaction results show that the polyoxometalate and carboxylic acid groups have significant effects on the catalytic activity, which can improve the efficiency of ODS. Radical scavenger analysis results indicate that the synergistic effect proceeds from the O₂^•- radical pathway. EDX analysis and characterization of the recovered catalyst do not show significant leaching of the catalytic active component.