Measurement of infinite dilution partition coefficients of isomeric benzene derivatives in [bmim][Tf2N]-CO2 biphasic system and correlation with the ePC-SAFT equation of state

Yuya Hiraga, Yoshiyuki Sato, Richard L. Smith

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5 Citations (Scopus)

Abstract

Infinite dilution partition coefficients of isomeric benzene derivatives in the [bmim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide)-CO2 biphasic system were measured with a supercritical fluid chromatography technique at pressures of 6–15 MPa and at temperatures of 313–353 K. The partition coefficients of o-cresol were always larger than those of m and p-cresol, while those of o-xylene were always smaller than those of m and p-xylene for all temperatures and pressures. The partition coefficients of the solutes in the ionic liquid-CO2 systems were found to be in the order of their vapor pressure in accordance with previous reports. The partition coefficient data were correlated with the ePC-SAFT (electrolytes perturbed-chain statistical associating fluid theory) equations and with the empirical LSER (Linear Solvation Energy Relationship)-δ model. The overall average relative deviation (ARD) of the ePC-SAFT equation using interaction parameters between ionic liquid and solute as fitting parameters was 8.2% and compared well with the LSER-δ model (7.5%). In one approach to improve the prediction capability of the ePC-SAFT equation, literature data of infinite dilution activity coefficients of toluene in the [bmim][Tf2N]-toluene biphasic system at atmospheric pressure were used to determine ePC-SAFT interaction parameters between [bmim][Tf2N] and toluene. Although this approach improved the ePC-SAFT description of the [bmim][Tf2N]–CO2–toluene system, the correlation was qualitative at high pressure and can be attributed to CO2 in the liquid phase that affects [bmim][Tf2N]-toluene interactions.

Original languageEnglish
Pages (from-to)36-43
Number of pages8
JournalFluid Phase Equilibria
Volume420
DOIs
Publication statusPublished - 2016 Jan 1

Keywords

  • Equation of state
  • Ionic liquid
  • PC-SAFT
  • Supercritical carbon dioxide

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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