Korean Journal of Chemical Engineering

, Volume 19, Issue 3, pp 357–362 | Cite as

Room temperature ionic liquids as replacements for conventional solvents – A review

  • Kenneth N. MarshEmail author
  • Alex Deev
  • Alex C-T. Wu
  • Emma Tran
  • A. Klamt
Featured review


Room temperature ionic liquids are salts that are liquids at ambient temperature. They are excellent solvents for a broad range of polar organic compounds and they show partial miscibility with aromatic hydrocarbons. Typical room temperature ionic liquids have a stable liquid range of over 300 K and have a very low vapor pressure at room temperature. Ionic liquids that are not hydrolyzed show a wide range of solubility in water. These unique properties have suggested that they might be useful as environmentally benign solvents that could replace volatile organic compounds (VOC). By varying the length and branching of the alkane chains of the cationic core and the anionic precursor, the solvent properties of ionic liquids should be able to be tailored to meet the requirements of specific applications to create an almost infinitely set of “designer solvents”. A review of recent applications of ionic liquids is presented along with some results of measurements of liquid-liquid equilibria and partition coefficients with alcohols. The results are compared with predictions based on quantum mechanic calculations.

Key words

Ionic Liquids Liquid-Liquid Equilibria Prediction Quantum Chemical Calculations 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Anthony, J. L., Maginn, E. J. and Brennecke, J. F., “Solution Thermodynamics of Imidazolium Based Ionic Liquids and Water”,J. Phys. Chem. B,105, 10942 (2001).CrossRefGoogle Scholar
  2. Armstrong, D. W., He, L. and Liu, Y, “Examination of Ionic Liquids and Their Interaction with Molecules, When Used as Stationary Phases in Gas Chromatography”,Anal. Chem.,71, 3873 (1999).CrossRefGoogle Scholar
  3. Bates, E. D., Mayton, R. D., Ntai, I. and Davis, J. H., “CO2 Capture by a Task-Specific Ionic Liquid”,J. Am. Chem. Soc,124, 926 (2002).CrossRefGoogle Scholar
  4. Blanchard, L. A. and Brennecke, J. F., “Recovery of Organic Products from Ionic Liquids using Supercritical Carbon Dioxide”,Ind. Eng. Chem. Res.,40, 287 (2001).CrossRefGoogle Scholar
  5. Blanchard, L. A., Gu, Z. and Brennecke, J. F., “High Pressure Phase Behavior of Ionic Liquids/CO2 Systems”,J. Phys. Chem. B,105, 2437 (2001).CrossRefGoogle Scholar
  6. Blanchard, L. A., Hancu, D., Beckman, E. J. and Brennecke, J. F., “Green Processing using Ionic Liquids and CO2”,Nature,399, 28 (1999).CrossRefGoogle Scholar
  7. BÔnhote, P., Dias, A.-P., Papageorgiou, N., Kalyanasundaram, K. and Graetzel, M., “Hydrophobic, Highly Conductive Ambient-Temperature Molten Salts”,Inorg. Chem.,35, 1168 (1996).CrossRefGoogle Scholar
  8. Boesmann, A., Datsevich, L., Jess, A., Lauter, A., Schmitz, C. and Wasserscheid, P., “Deep Desulfurization of Diesel Fuel by Extraction with Ionic Liquids”,Chem. Comm.,23, 2494 (2001).CrossRefGoogle Scholar
  9. Brennecke, J. F. and Maginn, E. J., “Ionic Liquids: Innovative Fluids for Chemical Processing”,AIChE J.,47, 2384 (2001).CrossRefGoogle Scholar
  10. Chauvin, Y., Mussmann, L. and Olivier, H., “A Novel Class of Versatile Solvents for Two-Phase Catalysis: Hydrogenation, Isomerisation, and Hydroformylation of Alkenes Catalyzed by Rhodium Complexes in Liquid 1,3-Dialkylimidazolium Salts”,Angew. Chem. Int. Ed. Engl.,34, 2698 (1995).CrossRefGoogle Scholar
  11. Cull, S. G., Holbrey, J. D, Vargas-Mora, V., Seddon, K. R. and Lye, G. J., “Room-Temperature Ionic Liquids as Replacements for Organic Solvents in Multiphase Bioprocess Operations”,Biotech. Bioeng.,69, 227 (2000).CrossRefGoogle Scholar
  12. Erbeldinger, M., Mesiano, A. J. and Russell, A. J., “Enzymatic Catalysis of Formation of Z-Aspartame in Ionic Liquid-An Alternative to Enzymatic Catalysis in Organic Solvents”,Biotechnol. Prog.,16, 1129 (2000).CrossRefGoogle Scholar
  13. Fannin, A. A., Jr., Floreani, D. A., King, L. A., Landers, J. S., Piersma, B. J., Stech, D. J., Vaughn, R. L., Wilkes, J. S. and Williams, J. L., “Properties of 1,3-Dialkylimidazolium Chloride-Aluminium Chloride Ionic Liquids. 2. Phase Transitions, Densities, Electrical Conductivities, and Viscosities”,J. Phys. Chem.,88, 2614 (1984).CrossRefGoogle Scholar
  14. Fuller, J., Carlin, R. T. and Osteryoung, R. A., “The Room Temperature Ionic Liquid 1-Ethyl-3-methylimidazolium Tetrafluoroborate: Electrochemical Couples and Physical Properties”,J. Electrochem. Soc.,144, 3881 (1997).CrossRefGoogle Scholar
  15. Huddleston, J. G., Willauer, H. D., Swatloski, R. P., Visser, A. E. and Rogers, R. D., “Room Temperature Ionic Liquids as Novel Media for Clean Liquid-Liquid Extraction”, Chem. Commun., 1765 (1998).Google Scholar
  16. Huddleston, J. G., Visser, A. E., Reichert, W. M., Willauer, H. D., Broker, G. A. and Rogers, R. D., “Characterization and Comparison of Hydrophilic and Hydrophobic Room Temperature Ionic Liquids Incorporating the Imidazolium Cation”,Green Chemistry,3, 156 (2001).CrossRefGoogle Scholar
  17. Klamt, A. and Eckert, F., “COSMO-RS: A Novel and Efficient Method for the a priori Prediction of the Thermophysical Data of Liquids”,Fluid Phase Equilib.,172, 43 (2000).CrossRefGoogle Scholar
  18. Koel, M., “Physical and Chemical Properties of Ionic Liquids Based on the Dialkylimidazolium Cation”,Proc. Est. Acad. Sci., Chem.,49, 145 (2000).Google Scholar
  19. Kaufmann, D. E., Nouroozian, M. and Henze, H., “Molten Salts as an Efficient Medium for Palladium-Catalysed C-C Coupling Reactions”,Synlett, 1091 (1996).Google Scholar
  20. Liao, Q. and Hussey, L., “Densities, Viscosities, and Conductivities of Mixtures of Benzene with the Lewis Acidic Aluminium Chloride+1- Methyl-3-ethylimidazolium Chloride Molten Salt”,J. Chem. Eng. Data,41,1126 (1996).CrossRefGoogle Scholar
  21. Müller, L. A., DuPont, J. and De Souza, R. F., “Two-phase Catalytic NBR Hydrogenation by RuHCl(CO)(PCy3)2 Immobilized in 1- Butyl-3-methylimidazolium Tetrafluoroborate Molten Salt”,Macromol. Rapid Communun.,19, 409 (1998)CrossRefGoogle Scholar
  22. Ngo, H. L., LeCompte, K., Hargens, L. and McEwen, A. B., “Thermal Properties of Imidazolium Ionic Liquids”,Thermochim. Acta,357–358, 97 (2000).CrossRefGoogle Scholar
  23. Seddon, K. R. Private Communication (2001).Google Scholar
  24. Seddon, K. R., Stark, A. and Torres, M. J., “Influence of Chloride, Water, and Organic Solvents on the Physical Properties of Ionic Liquids”,Pure Appl. Chem.,72, 2275 (2000).Google Scholar
  25. Silva, S. M., Suarez, P. A. Z., de Souza, R. F. and DuPont, J., “Selective Linear Dimerization of 1,3-Butadiene by Palladium Compounds Immobilized into l-n-Butyl-3-methyl Imidazolium Ionic Liquids”,Polmer Bull.,40, 401 (1998).CrossRefGoogle Scholar
  26. Suarez, P. A. Z., Dullius, J. E. L., Einoft, S., de Souza, R. F. and Dupont, J., “Two-Phase Catalytic Hydrogenation of Olefins by Ru(II) and Co(II) Complexes Dissolved in l-n-Butyl-3-methyl Imidazolium tetrafluoroborate Ionic Liquid”,Inorganica Chimica Acta,255, 207 (1997).CrossRefGoogle Scholar
  27. Suarez, P. A. Z., Einoft, S., Dullius, J. E. L., de Souza, R. F. and Dupont, J., “Synthesis and Physical-Chemical Properties of Ionic Liquids Based on l-n-Butyl-3-Methylimidazolium Cation”,J. Chim. Phys. Phys.-Chim. Biol.,95, 1626 (1998).CrossRefGoogle Scholar
  28. Wasserscheid, P. and Keim, W., “Ionic Liquids-New ‘Solutions’ for Transition Metal Catalysis”,Agnew. Chem. Int. Ed,39, 3772 (2000).CrossRefGoogle Scholar
  29. Welton, T., “Room-Temperature Ionic Liquids. Solvents for Synthesis and Catalysis”,Chem. Rev.,99, 2071 (1999).CrossRefGoogle Scholar
  30. Welton, T. private communication (2000).Google Scholar
  31. Wong, D. S. H., Chen, J. P., Chang, J. M. and Chou, C. H., “Phase Equilibria of Water and Ionic Liquids [emim][PF6] and [bmim][PF6]”,Fluid Phase Equilib. in press (2002).Google Scholar

Copyright information

© Korean Institute of Chemical Engineering 2002

Authors and Affiliations

  • Kenneth N. Marsh
    • 1
    Email author
  • Alex Deev
    • 1
  • Alex C-T. Wu
    • 1
  • Emma Tran
    • 1
  • A. Klamt
    • 1
    • 2
  1. 1.Department of Chemical and Process EngineeringUniversity of CanterburyNew Zealand
  2. 2.CosmologicLeverkusenGermany

Personalised recommendations