High-Pressure Densities and Derived Thermodynamic Properties of Imidazolium-Based Ionic Liquids

Ramesh Gardas, M.G. Freire, P.J. Carvalho, I.M. Marrucho, I.M.A. Fonseca, A.G.M. Ferreira, J.A.P. Coutinho

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356 Citations (Scopus)


This work addresses the experimental measurements of the pressure (0.10 <p/MPa <10.0) and temperature (293.15 <T/K <393.15) dependence of the density and derived thermodynamic properties, such as the isothermal compressibility, the isobaric expansivity, the thermal pressure coefficient, and the pressure dependence of the heat capacity of several imidazolium-based ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4]; 3-methyl-1-octylimidazolium tetrafluoroborate, [omim][BF4]; 1-hexyl-3-methylimidazolium hexafluorophosphate, [hmim][PF6]; 3-methyl-1-octylimidazolium hexafluorophosphate, [omim][PF6]; 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, [bmmim][PF6]; and 1-butyl-3-methylimidazolium trifluoromethansulfonate, [bmim][CF3SO3]. These ILs were chosen to provide an understanding of the influence of the cation alkyl chain length, the number of cation substitutions, and the anion influence on the properties under study. The influence of water content in the density was also studied for the most hydrophobic IL used, [omim][PF6]. A simple ideal-volume model was employed for the prediction of the imidazolium molar volumes at ambient conditions, which proved to agree well with the experimental results.
Original languageEnglish
Pages (from-to)80-88
Number of pages9
JournalJournal of Chemical and Engineering Data
Volume52 (1)
Issue number1
Publication statusPublished - Jan 2007

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Chemistry(all)


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