Solvent strength of ionic liquid/CO2 mixtures

C.P. Fredlake, Mark Muldoon, S.N.V.K. Aki, T. Welton, J.F. Brennecke

Research output: Contribution to journalArticlepeer-review

78 Citations (Scopus)


Previously we have shown that organic solutes can be extracted from ionic liquids (ILs) with supercritical CO2 and that ILs can be induced to separate from organic and aqueous mixtures by applying gaseous CO2 pressure. Thus, we are interested in the solvent strength of IL/CO2 mixtures. Here we use 4-nitroaniline, N,N-diethyl-4-nitroaniline and Reichardt's dye 33 to determine the Kamlet-Taft parameters for four different imidazolium based ILs and their mixtures with CO2 at 25 and 40degreesC. The effect of temperature and carbon dioxide concentration on these parameters was determined. The polarizability parameter depends weakly on the CO2 concentration. However, the hydrogen bond donating ability and the hydrogen bond accepting ability are virtually independent Of CO2 pressure. The results indicate that the strong interactions between ILs and probe molecules are not influenced by CO2.
Original languageEnglish
Pages (from-to)3280-3285
Number of pages6
JournalPhysical Chemistry Chemical Physics
Issue number13
Publication statusPublished - 07 Jul 2004

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Atomic and Molecular Physics, and Optics


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