Binary Vapor-Liquid and Liquid-Liquid Equilibria of Task-Specific Ionic Liquids with Water

Task-specific ionic liquids (TSILs) are ionic liquids containing an appended functional group which chemically complexes with a solute molecule of interest. The TSILs in this study contain either one or two appended amine groups on the cation and/or anion which chemically react with carbon dioxide. The chemical complexation of the TSIL with carbon dioxide provides the potential for further carbon dioxide storage capacity than is possible in ionic liquids which only physically absorb carbon dioxide. In order for a TSIL to be effectively used in an adsorbing /stripping process to capture carbon dioxide, it is also necessary to determine its capacity for absorbing water because this will directly correlate to the amount of energy required to regenerate the TSIL during the stripping phase. Water solubility isotherms were determined experimentally with a Hiden Intelligent Gravimetric Analyser (IGA003) and are reported for various TSILs at 40⁰C at pressures below saturation (73.849 mbar) along with infinite dilution activity coefficients. In addition, gravimetrically determined liquid-liquid equilibrium values are reported for these TSILs with water at room temperature and atmospheric pressure.