Pressure, Isotope, and Water Co-solvent Effects in Liquid-Liquid Equilibria of (Ionic Liquid + Alcohol) Systems

V. Najdanovic-Visak, J.M.S.S. Esperança, L.P.N. Rebelo, M.N. Da Ponte, H.J.R. Guedes, K.R. Seddon, H.C. De Sousa, J. Szydlowski

Research output: Contribution to journalArticle

Abstract

Liquid−liquid phase splitting in ternary mixtures that contain a room-temperature ionic liquid and an alcohol aqueous solutionnamely, [bmim][PF6] + ethanol + water and [bmim][NTf2] + 2-methylpropanol + wateris studied. Experimental cloud-point temperatures were obtained up to pressures of 400 bar, using a He−Ne laser light-scattering technique. Although pressurization favors mutual miscibility in the presence of high concentrations of alcohols, the contrary occurs in water-rich solutions. Both ternary mixtures exhibit a very pronounced water−alcohol co-solvent effect. Solvent isotope effects are also investigated. Phase diagrams are discussed using a phenomenological approach based on a “polymer-like” GE model coupled with the statistical−mechanical theory of isotope effects. The combined effect of a red shift of −15 cm-1 for the O−H deformation mode of ethanol with a blue shift of +35 cm-1 for the O−H stretching mode, both of which occurring after liquid infinite dilution in the ionic liquid, rationalizes the observed isotope effect in the phase diagram. Predicted excess enthalpy (HE) values are inferred from the model parameters. Furthermore, using the Prigogine−Defay equation, an estimation of the excess volumes (VE) is obtained.
Original languageEnglish
Pages (from-to)12797-12807
JournalJournal of Physical Chemistry B
Volume107
Issue number46
DOIs
Publication statusPublished - 24 Oct 2003

Fingerprint Dive into the research topics of 'Pressure, Isotope, and Water Co-solvent Effects in Liquid-Liquid Equilibria of (Ionic Liquid + Alcohol) Systems'. Together they form a unique fingerprint.

  • Cite this

    Najdanovic-Visak, V., Esperança, J. M. S. S., Rebelo, L. P. N., Da Ponte, M. N., Guedes, H. J. R., Seddon, K. R., De Sousa, H. C., & Szydlowski, J. (2003). Pressure, Isotope, and Water Co-solvent Effects in Liquid-Liquid Equilibria of (Ionic Liquid + Alcohol) Systems. Journal of Physical Chemistry B, 107(46), 12797-12807. https://doi.org/10.1021/jp034576x