Extractive oxidative desulfurization of fuels using choline chloride and tetraethylene glycol-based eutectic solvent

Due to ever-increasing environmental problems, special attention has been paid to removing the organosulfur compounds present in transportation fuel. Therefore, to minimize the adverse effects of automotive exhaust emissions, sulfur level in motor fuels is minimized. Nowadays, DESs have become eco-friendly solvents due to their significant properties such as low toxicity, low volatility, etc. Thus, found attractive toward extraction process also. In this study, a series of DES using CHCl, MTTPBr, TEAC as HBA and PYG, EG, and TetEG as HBD in the different mole ratios were synthesized and investigated their extraction performance for sulfur in model and diesel fuels. Densities, viscosity & FTIR spectra of synthesized DESs were recorded. ODS was also performed for diesel. Results concluded that among all the synthesized DESs, [CHCl][TetEG](1:5) worked better for the desulfurization of fuels. In a single-stage, around 43% extraction efficiency was achieved for model sulfur compounds using [CHCl][TetEG](1:5), which can be enhanced up to 86% using successive extraction stages at low-temperature 30 °C. However, around 34% and 29%, respectively, extraction efficiency was achieved for diesel due to their complex nature. While on oxidation of diesel, it was increased up to 52% and 43% respectively in one single stage at a low-temperature 30 °C.