Removal of Thiophene and Its Derivatives from Model Gasoline Using Polymer-Supported Metal Chlorides Ionic Liquid Moieties

A series of polymer-supported metal chlorides imidazolium ionic liquid (IL) moieties, M/CMPS-Im(Cl) (M = CuCl, ZnCl2 and FeCl3), were synthesized by grafted method using chloromethylated polystyrene (CMPS) resin as support. Meanwhile, the structures of synthesized ILs were characterized by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). The results showed that the surface of CMPS resin was covered with a thin layer of extraction activity components. Then, the synthesized CMPS-supported imidazolium-based ILs were investigated to extract thiophene and its derivatives from model gasoline (n-octane/thiophene) under certain conditions. For a given imidazolium-based IL: first, the order of extraction capacity of extractant was CuCl/CMPS-Im(Cl) > ZnCl2/CMPS-Im(Cl) > FeCl3/CMPS-Im(Cl); the reason for this was that the pi-complexation capability between Cu+ and thiophene was stronger than those of Fe3+ and Zn2+. Second, the sulfur removal selectivity of sulfur compound followed the order of TS < BT < DBT under the same conditions; it indicated that the extraction was favored for those aromatic heterocyclic sulfur compounds with higher density aromatic pi-electrons density. Meanwhile, the effect of mass ratio of model gasoline to M/CMPS-Im(Cl) ILs, different initial sulfur concentrations, and extraction time on desulfurization rates of M/CMPS-Im (Cl) its was performed, respectively. Finally, regeneration of M/CMPS-Im(Cl) ILs was investigated.