Deep Extractive Desulfurization with Arenium Ion Deep Eutectic Solvents

Deep eutectic solvents (DESs), which were prepared by using AlCl3, chlorinated paraffins-52, and various aromatics, show excellent desulfurization performance to various thiophenic sulfur compounds. In DESs, aromatic compounds strongly influence the desulfurization performance, and the order is toluene > p-xylene > o-xylene > ethylbenzene > benzene > chlorobenzene. The DESs containing toluene (DES-T) can deeply remove the three thiophenic sulfur compounds, that is, 3-methylthiophene, benzothiophene, and dibenzothiophene, within 10 min at 293 K. The extractive desulfurization mechanism is considered to be a π–π interaction of the aromatic ring along with the acid–base complexation. Satisfactorily, the extractive desulfurization is still effective for real oils, and real oil quality is improved in this process.