We presented the first in situ FTIR spectroscopic study of ionic liquids subjected to high-pressure or supercritical CO2. The combination of these solvents provides a new opportunity for chemical synthesis and the purification and separation of reaction products. Implications of this work include broader applications of ionic liquids and supercritical fluids to chemical processes using the combination of these environmentally benign solvents.

Using ATR-FTIR spectroscopy we assessed the molecular state of water in a range of ionic liquids and demonstrated the major role of the nature of anions in interactions with water and in determining water solubility in ionic liquids. This information is needed for the technological use of ionic liquids as alternatives to volatile organic solvents in environmentally friendly programmes. The molecular state of water is fundamental for the properties of ionic liquids as evidenced by over 1500 citations of this work. This study is also one of the top cited papers published in Physical Chemistry Chemical Physics.

Key References:

  • Kazarian S. G., Briscoe B. J., Welton T. Combining Ionic Liquids and Supercritical Fluids: In Situ ATR-IR Study of CO2 Dissolved in Two Ionic Liquids at High-Pressures, Chemical Communications, (2000), 2047-2048. (doi)
  • Cammarata L., Kazarian S. G., Salter P., Welton T. Molecular states of water in room temperature ionic liquids, Physical Chemistry Chemical Physics 3 (2001) 5192-5200. (doi)
  •  Kazarian S. G., Sakellarios N., Gordon C. M. High-pressure CO2-induced reduction of the melting temperature of ionic liquids, Chemical Communications (2002) 1314-1315.
  •  Sakellarios N. I, Kazaian S. G. Solute partitioning between an ionic liquid and high-pressure CO2 studied with in situ FTIR spectroscopy, J. Chem. Thermodynamics. 37 (2005) 621-626.
  • Hojniak S.D.,  Silverwood I. P.,  Khan A. L., Vankelecom I. F. J.,  Dehaen W., Kazarian S. G., Binnemans K Highly Selective Separation of Carbon Dioxide from Nitrogen and Methane by Nitrile/Glycol-Difunctionalized Ionic Liquids in Supported Ionic Liquid Membranes (SILMs) J. Phys. Chem (2014) 118 (26), 7440–7449(doi)
  • Muginova S. V.,  Myasnikova D. A, Kazarian S. G., Shekhovtsova, T. N. Applications of Ionic Liquids for the Development of Optical Chemical Sensors and Biosensors   Analytical Sciences (2017)  33(3), 261-274 (doi)
  • Angelini G., Gasbarri, C., Kazarian S. G.  Pluronic L121, BMIM BF4 and PEG-400 comparison to identify the best solvent for CO2 sorption Journal of Molecular Liquids  (2018)  258, 85–88 (doi).
  • Shalygin A. S., Nesterov N.S., Prikhod’koS. A., Martyanov O.N., Kazarian S. G. Interactions of CO2 with the homologous series of СnMIMBF4 ionic liquids studied in situ ATR-FTIR spectroscopy: spectral characteristics, thermodynamic parameters and their correlation. Journal of Molecular Liquids  (2020)  315, 113694 (doi)
  • Chan K. L. A., Shalygin A. S., Martyuanov O. N., Welton T., Kazarian S. G. High throughput study of ionic liquids in controlled environments with FTIR spectroscopic imaging  Journal of Molecular Liquids (2021)  accepted and in press (doi).