Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Evaluation of the ionic liquids 1-alkyl-3-methylimidazolium hexafluorophosphate as a solvent for the extraction of benzene from cyclohexane: (Liquid + liquid) equilibria

Zhou, T.[Teng], Wang, Z.[Ziyun], Chen, L.[Lifang], Ye, Y.[Yinmei], Qi, Z.[Zhiwen], Freund, H.[Hannsjorg], Sundmacher, K.[Kai]
J. Chem. Thermodyn. 2012, 48, 145-149
ABSTRACT
In the catalytic hydrogenation of benzene to cyclohexane, the separation of unreacted benzene from the product stream is inevitable and essential for an economically viable process. In order to evaluate the separation efficiency of ionic liquids (ILs) as a solvent in this extraction processes, the ternary (liquid + liquid) equilibrium of 1-alkyl-3-methylimidazolium hexafluorophosphate, [Cnmim][PF6] (n = 4, 5, 6), with benzene and cyclohexane was studied at T = 298.15 K and atmospheric pressure. The reliability of the experimentally determined tie-line data was confirmed by applying the Othmer-Tobias equation. The solute distribution coefficient and solvent selectivity for the systems studied were calculated and compared with literature data for other ILs and sulfolane. It turns out that the benzene distribution coefficient increases and solvent selectivity decreases as the length of the cation alkyl chain grows, and the ionic liquids [Cnmim][PF6] proved to be promising solvents for benzene cyclohexane extractive separation. Finally, an NRTL model was applied to correlate and fit the experimental LLE data for the ternary systems studied.
Compounds
# Formula Name
1 C6H6 benzene
2 C6H12 cyclohexane
3 C8H15F6N2P 1-butyl-3-methylimidazolium hexafluorophosphate
4 C9H17F6N2P 1-methyl-3-pentylimidazolium hexafluorophosphate
5 C10H19F6N2P 1-hexyl-3-methylimidazolium hexafluorophosphate
Datasets
The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type Compound-# Property Variable Constraint Phase Method #Points
  • POMD
  • 1
  • 2
  • 3
  • Mole fraction - 2 ; Liquid mixture 2
  • Mole fraction - 2 ; Liquid mixture 1
  • Mole fraction - 1 ; Liquid mixture 1
  • Mole fraction - 1; Liquid mixture 2
  • Pressure, kPa; Liquid mixture 2
  • Temperature, K; Liquid mixture 2
  • Liquid mixture 2
  • Liquid mixture 1
  • Chromatography
  • Chromatography
  • Chromatography
  • 8
  • POMD
  • 1
  • 2
  • 4
  • Mole fraction - 2 ; Liquid mixture 1
  • Mole fraction - 2 ; Liquid mixture 2
  • Mole fraction - 1 ; Liquid mixture 2
  • Mole fraction - 1; Liquid mixture 1
  • Temperature, K; Liquid mixture 2
  • Pressure, kPa; Liquid mixture 2
  • Liquid mixture 1
  • Liquid mixture 2
  • Chromatography
  • Chromatography
  • Chromatography
  • 8
  • POMD
  • 1
  • 2
  • 5
  • Mole fraction - 2 ; Liquid mixture 1
  • Mole fraction - 2 ; Liquid mixture 2
  • Mole fraction - 1 ; Liquid mixture 2
  • Mole fraction - 1; Liquid mixture 1
  • Temperature, K; Liquid mixture 2
  • Pressure, kPa; Liquid mixture 2
  • Liquid mixture 1
  • Liquid mixture 2
  • Chromatography
  • Chromatography
  • Chromatography
  • 8