Excess molar volumes and excess molar enthalpies in binary systems N-alkyl-triethylammonium bis(trifluoromethylsulfonyl)imide plus methanol

Karolina Machanova*, Jacobo Troncoso, Johan Jacquemin, Magdalena Bendova

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

In the present paper, a study on the influence of the alkyl chain length in N-alkyl-triethylammonium bis(trifluoromethylsulfonyl)imide ionic liquids, [NR,222][Tf2N] (R   = 6, 8 or 12), on the excess molar enthalpy at 303.15 K and excess molar volume within the temperature interval (283.15–338.15 K) of ionic liquid + methanol mixtures is carried out. Small excess molar volumes with highly asymmetric curves (i.e. S-shape) as a function of mole fraction composition were obtained, with negative values showing in the methanol-rich regions. The excess molar volumes increase with the increase of the alkyl-chain length of the ammonium cation of the ionic liquid and decrease with temperature. The excess enthalpies of selected binary mixtures are positive over the whole composition range and increase slightly with the length of the alkyl side-chain of the cation on the ionic liquid. Both excess properties were subsequently correlated using a Redlich–Kister-type equation, as well as by using the ERAS model. From this semipredictive model the studied excess quantities could be obtained from its chemical and physical contribution. Finally, the COSMOThermX software has been used to evaluate its prediction capability on the excess enthalpy for investigated mixtures at 303.15 K and 0.1 MPa. From this work, it appears that COSMOThermX method predicts this property with good accuracy of approx. 10%, providing at the same time the correct order of magnitude of the partial molar excess enthalpies at infinite dilution for the studied ILs,

<img height="21" border="0" style="vertical-align:bottom" width="33" alt="View the MathML source" title="View the MathML source" src="http://origin-ars.els-cdn.com/content/image/1-s2.0-S0378381213006869-si13.gif">H¯1E,∞, and methanol, <img height="21" border="0" style="vertical-align:bottom" width="33" alt="View the MathML source" title="View the MathML source" src="http://origin-ars.els-cdn.com/content/image/1-s2.0-S0378381213006869-si14.gif">H¯2E,∞.
Original languageEnglish
Pages (from-to)156-166
Number of pages11
JournalFluid Phase Equilibria
Volume363
Early online date02 Dec 2013
DOIs
Publication statusPublished - 15 Feb 2014

Keywords

  • Ionic liquids
  • Excess volume
  • Excess enthalpy
  • ERAS
  • COSMO-RS
  • TEMPERATURE IONIC LIQUIDS
  • ERAS MODEL
  • ASYMMETRIC HYDROGENATION
  • THERMODYNAMIC PROPERTIES
  • PHYSICAL-PROPERTIES
  • SURFACE-TENSION
  • GAS SOLUBILITY
  • RU-BINAP
  • MIXTURES

Cite this