Globe Trotting Distinguished Faculty
Distinguished Foundation Professor Mark Shiflett was in beautiful Graz, Austria this week at the world renowned European Conference on Thermophysical Properties. The title of his presentation was “Ionic Liquids – Phase Behavior to Applications.” (A full abstract will be posted below.)
We are extremely proud to have Dr. Shiflett represent our department as well as the CEBC and KU at this amazing event. To learn more about the conference, click here. Other invited speakers included Michal Fulem from UCT Prague, Hioyuki Shibata from Tohoku University, Manuel Monte from the University of Porto, Douglas Matson from Tufts University, and Boris Wilthan from NIST. To read their full profiles, click here.
Presentation Abstract: “The history of ionic liquids (ILs) effectively started in 1914, when the physical properties of ethylammonium nitrate ([CH3CH2NH3+][NO3-], m.p. 13-14 °C) were first reported. ILs are generally defined as salts composed of discrete cations and anions with melting points below 100 °C, and many are liquid at ambient temperature. IL research has grown rapidly over the past two decades due to the realization that these materials have many unique properties such as negligible vapor pressure and outstanding solvation potential. Ionic liquids have been further emphasized by the fact that their physical and chemical properties can be finely tuned by varying both the cation and anion. Our research has focused on accurately measuring vapor-liquid equilibria (VLE) and vapor-liquid-liquid equilibria (VLLE) and using thermodynamic models to understand the phase behavior of binary gas mixtures in ILs. This presentation will focus on the importance of characterizing the global phase behavior of gases in ionic liquids and how this can provide insight into new applications. Solubility measurements of several gases in ILs will be discussed and important experimental details regarding VLE measurements using a gravimetric microbalance and VLLE measurements using a mass-volume technique will be highlighted. VLE data have been successfully correlated with a modified Redlich-Kwong equation of state (EOS), and in certain cases (e.g. hydrofluorocarbons) the EOS predicts partial immiscibilities (LLE) with lower critical solution temperatures (LCSTs) in the fluorocarbon-rich side solutions. We have also found that gases such as CO2 can exhibit different solubility behaviors in ILs (i.e. physical and chemical absorption) and that these behaviors can be analyzed with the EOS using a simple association model and excess thermodynamic functions. Knowledge of gas and IL phase behavior has led to several practical applications including separation of azeotropic gas mixtures, removal of CO2 from flue gas and new fluid pairs for absorption cooling. These along with other interesting examples from the literature will be discussed.”