title: Hydrophobic task-specific ionic liquids: synthesis, properties and application for the capture of SO2.
abstract: The capture of SO2 by ionic liquids (ILs) has drawn much attention all over the world. However, ILs can absorb not only SO2 but also water from flue gas. The removal of water from ILs is necessary for reusing the absorbent. In order to reduce the energy costs of removing water, it would be helpful to weaken the interactions between ILs and water. In this work, two kinds of hydrophobic task-specific ILs, 1-(2-diethyl-aminoethyl)-3-methylimidazolium hexafluorophosphate ([Et2NEmim] [PF6]) and 1-(2-diethyl-aminoethyl)-1-methylpyrrolidinium hexafluorophosphate ([Et2NEmpyr][PF6]), were designed and synthesized. Thermal stability and physical properties of the ILs were studied. Furthermore, the application of the ILs for the capture of SO2 and the absorption mechanism were systematically investigated. It has been found that both of the ILs are immiscible with water, and [Et2NEmim][PF6] has much lower viscosity, much higher thermal stability and much higher SO2 absorption rate than [Et2NEmpyr][PF6]. [Et2NEmim][PF6] shows high SO2 absorption capacities up to 2.11 mol SO2 per mole IL (pure SO2) and 0.94 mol SO2 per mole IL (3% SO2) under hydrous conditions at 30 °C. The result suggests that [Et2NEmim][PF6] is a promising recyclable absorbent for the capture of SO2.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Shidong
authors.initials: S
authors.lastname: Tian
authors.affiliation: Department of Chemistry, Taiyuan Normal University, Taiyuan 030031, China.
authors.forename: Yucui
authors.initials: Y
authors.lastname: Hou
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: wzwu@mail.buct.edu.cn.
authors.forename: Weize
authors.initials: W
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Shuhang
authors.initials: S
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Qian
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D052578:Ionic Liquids / Q000737:chemistry*; D059027:Recycling; D013458:Sulfur Dioxide / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D052578:Ionic Liquids; D014867:Water; D013458:Sulfur Dioxide
keywords: Hydrophobic ionic liquid; Property; SO(2) capture; Synthesis