Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

Effect of cation alkyl chain length on liquid-liquid equilibria of {ionic liquids + thiophene + heptane}: COSMO-RS prediction and experimental verification

Song, Z.[Zhen], Zhang, J.[Jingjing], Zeng, Q.[Qian], Cheng, H.[Hongye], Chen, L.[Lifang], Qi, Z.[Zhiwen]
Fluid Phase Equilib. 2016, 425, 244-251
ABSTRACT
When selecting ionic liquid (IL) as solvent for extraction processes, the cation alkyl chain length is an important structural variation, while research particularly concerning its effect is lacking. In this work, the effect of cation alkyl chain length on the liquid-liquid equilibria of {IL + thiophene + heptane}, an example for extractive desulfurization, was systematically investigated. The COSMO-RS model was employed to calculate the distributional coefficient and selectivity at infinite dilution for thiophene of the combinations of 17 cations and 63 anions. Two different anion-dependent tendencies of the distributional coefficient with increasing the cation alkyl chain length were identified and analyzed by COSMO-RS theory. To verify the scarcely-reported decreasing distributional coefficient with longer cation alkyl chain, acetate ([OAc]-) was selected as representative and liquid-liquid equilibria {[CnMIM][OAc] + thiophene + heptane} (n = 2, 4, 6, 8) were experimentally determined, which validate the anion-dependency and demonstrate the highest extraction performance of [C2MIM][OAc].
Compounds
# Formula Name
1 C7H16 heptane
2 C4H4S thiophene
3 C8H14N2O2 1-ethyl-3-methylimidazolium acetate
4 C10H18N2O2 1-butyl-3-methylimidazolium acetate
5 C12H22N2O2 3-hexyl-1-methylimidazolium acetate
6 C14H26N2O2 1-methyl-3-octylimidazolium acetate
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 - 3 ; Liquid mixture 2
  • Mole fraction - 2 ; Liquid mixture 1
  • Mole fraction - 3 ; Liquid mixture 1
  • Mole fraction - 2; Liquid mixture 2
  • Temperature, K; Liquid mixture 1
  • Pressure, kPa; Liquid mixture 1
  • Liquid mixture 2
  • Liquid mixture 1
  • OTHER
  • OTHER
  • OTHER
  • 7
  • POMD
  • 1
  • 2
  • 4
  • Mole fraction - 4 ; Liquid mixture 2
  • Mole fraction - 2 ; Liquid mixture 1
  • Mole fraction - 4 ; Liquid mixture 1
  • Mole fraction - 2; Liquid mixture 2
  • Temperature, K; Liquid mixture 1
  • Pressure, kPa; Liquid mixture 1
  • Liquid mixture 2
  • Liquid mixture 1
  • OTHER
  • OTHER
  • OTHER
  • 7
  • POMD
  • 1
  • 2
  • 5
  • Mole fraction - 5 ; Liquid mixture 2
  • Mole fraction - 2 ; Liquid mixture 1
  • Mole fraction - 5 ; Liquid mixture 1
  • Mole fraction - 2; Liquid mixture 2
  • Temperature, K; Liquid mixture 1
  • Pressure, kPa; Liquid mixture 1
  • Liquid mixture 2
  • Liquid mixture 1
  • OTHER
  • OTHER
  • OTHER
  • 7
  • POMD
  • 1
  • 2
  • 6
  • Mole fraction - 6 ; Liquid mixture 2
  • Mole fraction - 2 ; Liquid mixture 1
  • Mole fraction - 6 ; Liquid mixture 1
  • Mole fraction - 2; Liquid mixture 2
  • Temperature, K; Liquid mixture 1
  • Pressure, kPa; Liquid mixture 1
  • Liquid mixture 2
  • Liquid mixture 1
  • OTHER
  • OTHER
  • OTHER
  • 7