ARTICLE IN PRESS JID: JTICE [m5G;October 22, 2016;13:24] Journal of the Taiwan Institute of Chemical Engineers 000 (2016) 1–7 Contents lists available at ScienceDirect Journal of the Taiwan Institute of Chemical Engineers journal homepage: www.elsevier.com/locate/jtice Mutual solubility of acidic ionic liquid and model gasoline of n-octane + 1-octene + toluene Shurong Gao a , Xiaochun Chen a,∗ , Rashid Abro a , Zhan Su a , Ahmed A. Abdeltawab b , Salem S. Al-Deyab b , Guangren Yu a,∗ a Beijing Key Laboratory of Membrane Science and Technology & College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China b Department of Chemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia a r t i c l e i n f o Article history: Received 9 March 2016 Revised 13 September 2016 Accepted 7 October 2016 Available online xxx Keywords: Desulfurization Fuel oil Ionic liquids Mutual solubility COSMO-RS a b s t r a c t Extractive and oxidative desulfurization of fuel oil using ionic liquids (ILs) as solvents have been inten- sively 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., [C 1 pyr]H 2 PO 4 , [C 1 pyr]Cl/ZnCl 2 , [BMIM]H 2 PO 4 , [BMIM]Cl/ZnCl 2 , [BPy]H 2 PO 4 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 under- stand 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 af- fecting the mutual solubility of ILs and fuel oil and is expected to contribute to the rational selection of conditions and ILs for desulfurization. © 2016 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers. 1. Introduction Desulfurization of fuel oil is an important process in oil refin- ing. Hydrodesulfurization (HDS) is widely employed in industry [1]. Increasing environmental concerns, more stringent statutory limits [2] (Fig. 1) imposed on sulfur content (S-content) in fuel oil [3,4], and the ineffectiveness of HDS to remove cyclic S-compounds have driven researchers to seek alternative desulfurization methods to HDS. Recently, ionic liquids (ILs) have attracted interests as solvents substituting traditional volatile organic solvents in extractive desul- furization (EDS) and oxidative desulfurization (ODS) [5–9]. Owing to the overwhelming advantages of ILs such as nonvolatility, high thermal/chemical stability, wide liquidus range, non-flammability and tunable dissolving or extracting capability for inorganic or or- ganic compounds, some problems from using volatile organic sol- ∗ Corresponding authors. Fax: +86 1064433570. E-mail addresses: chenxc@mail.buct.edu.cn (X. Chen), gryu@mail.buct.edu.cn (G. Yu). vents such as solvent loss and difficult recovery are avoided by em- ploying ILs. It has been observed that such EDS and ODS using ILs can effectively remove those HDS-immune cyclic S-compounds and reduce the S-component in fuel oils to less than 10 ppm [10–12], which presents a good industrial prospect. Many concerns are focused on S-removal efficiency [12–16]; the mutual solubility of ILs and fuel oil, however, is rarely taken into account [17,18]. It is simply presumed that ILs does not dis- solve into fuel oils [19,20]. However, Meindersma et al. [21] ob- served that the solubility of [C 4 mpy][BF 4 ] and [C 2 mim][EtSO 4 ] in n-heptane were 0.3 mol% and 0.9 mol%, respectively. Lu et al. [22] observed the solubility of piperazinium-based ILs in n-heptane was about 1 w%, while the solubility of some gasoline in ILs were in the range of 0.7–7 w%. The mutual solubilities between ILs and aromatics or aliphatics were also observed [23–26]. Although these references above have showed results on the mutual solubility of ILs with hydrocarbons, the solubility data available do not allow any discussion on the factors of ILs or hydrocarbons affecting the mutual solubility, and are not adequate for understanding of the mutual solubility of ILs and fuel oil. To identify the ILs to be used in particular applications of desulfurization, it is necessary to know http://dx.doi.org/10.1016/j.jtice.2016.10.008 1876-1070/© 2016 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers. Please cite this article as: S. Gao et al., Mutual solubility of acidic ionic liquid and model gasoline of n-octane + 1-octene + toluene, Journal of the Taiwan Institute of Chemical Engineers (2016), http://dx.doi.org/10.1016/j.jtice.2016.10.008