Understanding temperature dependency of hydrogen solubility in ionic liquids, including experimental data in [bmim][Tf2N]


  • Sona Raeissi,

    Corresponding author
    1. School of Chemical and Petroleum Engineering, Shiraz University, Shiraz 71345, Iran
    • School of Chemical and Petroleum Engineering Shiraz University, Shiraz 71345, Iran
    Search for more papers by this author
  • Cor J. Peters

    1. Dept. of Process and Energy, Faculty of Mechanical, Maritime and Materials Engineering, Laboratory of Process Equipment, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands
    2. The Petroleum Institute, Chemical Engineering Dept., Abu Dhabi, United Arab Emirates
    3. Dept. of Chemical Engineering and Chemistry, Separation Technology Group, Eindhoven University of Technology, Eindhoven, The Netherlands
    Search for more papers by this author


Previously unavailable high-pressure solubility data of hydrogen in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide has been measured experimentally up to temperatures and pressures of 450 K and 15 MPa, respectively. In contrast to CO2 solubility, H2 tends to dissolve better in the ionic liquid at higher temperatures. This “inverse” temperature effect has been studied from a thermodynamic perspective and the underlying reason for this effect is explained. It is shown that the negative P-T slope is not limited to this particular binary mixture, but is the typical behavior in most, if not all, H2 + ionic liquid systems. However, there is a certain range of temperatures, pressures, and concentrations in which this phenomenon occurs. By predicting the Scott-van Konynenburg phase diagram for systems of H2 + ionic liquids to be of type III, it is shown how and why the solubility increases with temperature in some regions, but decreases in others. © 2012 American Institute of Chemical Engineers AIChE J, 2012