Abstract
•Mutual solubility of ILs and fuel oil were determined by experimental and COSMO-RS method.•A variety of factors affecting the mutual solubility were investigated.•Desulfurization is favorably performed in a lower temperature.•ILs composed of anions/cations with stronger HB acceptor/donor capacity are more soluble in fuel oils.•Polar components dissolving in ILs have big influence on the mutual solubility.
Extractive and oxidative desulfurization of fuel oil using ionic liquids (ILs) as solvents have been intensively studied recently. In such processes, the mutual solubility of ILs and fuel oil is an issue that has to be addressed, and less mutual solubility is desired. In this work, we synthesized five kinds of ILs, i.e., [C1pyr]H2PO4, [C1pyr]Cl/ZnCl2, [BMIM]H2PO4, [BMIM]Cl/ZnCl2, [BPy]H2PO4 and studied their mutual solubility with fuel oil by employing experiment and conductor-like screening model for real solvents (COSMO-RS). A variety of factors such as time, IL structure, temperature, polar component in ILs and composition of fuel oil on the mutual solubility were investigated, and σ-profiles were used to understand the mutual solubility. ILs, which investigated in this work, composed of anions with stronger HB acceptor capacity and cations with stronger HB donor capacity, dissolving some polar components such as water and methanol, are more soluble in fuel oils with more polar components; while the fuel oils are more soluble in ILs with anions that have strong HB acceptor capacity and with cations that have strong HB donor capacity. The factors uncovered will provide some information for researchers, the factors affecting the mutual solubility of ILs and fuel oil and is expected to contribute to the rational selection of conditions and ILs for desulfurization.
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