Oxidative-Extractive Desulfurization of Model Fuels Using a Pyridinium Ionic Liquid

Abstract

In this research, <i>N</i>-butyl-pyridinium tetrafluoroborate ([BPy][BF₄]) ionic liquid (IL) was synthesized and characterized by ¹H-NMR, ¹³C-NMR, and FT-IR spectroscopy. The synthesized ionic liquid was employed as an extractive agent for the removal of dibenzothiophene (DBT), a typical organosulfur pollutant from the organic medium. The effect of extractive desulfurization on a model fuel with DBT was investigated. The impact of operating parameters, i.e., temperature, extraction time, IL-to-fuel ratio, and fuel to oxidizing agent ratio, on the extraction efficiency was investigated. It was observed that the IL to model fuel ratio and the H₂O₂ dosage have significant effects on desulfurization efficiency. An 89.49% DBT removal efficiency was obtained at a temperature of 30 °C after 35 min of extraction when the volume ratio of IL:model fuel:H₂O₂ was 1:1:0.04. A density functional theory (DFT) study was carried out to investigate the interactions between the IL and the sulfur-containing compounds DBT/DBTO₂.