Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

Ionic Liquid Based Aqueous Biphasic Systems with Controlled pH: The Ionic Liquid Cation Effect

Ventura, S.[Sonia], Sousa, S.[Silvia], Serafim, L.[Luisa], Lima, A.[Alvaro], Freire, M.[Mara], Coutinho, J. A.[Joao AP]
J. Chem. Eng. Data 2011, 56, 11, 4253-4260
ABSTRACT
This work addresses the evaluation of the ability of ionic liquid cations on the formation of aqueous biphasic systems (ABS's), with K2HPO4 or a mixture of inorganic salts, K2HPO4/KH2PO4, aiming at controlling the pH values of the coexisting aqueous phases. Using chloride-based ionic liquids, the effects of the cation core, the length of the alkyl side chain, and the positional isomerism on ABS formation ability were investigated. All binodal curves were determined by the cloud-point titration method at 298 K. From the obtained phase diagrams it is shown that the biphasic area increases with the cation side chain length, from ethyl to hexyl chains, although for longer chains, an inversion on the binodal curves sequence appears due to the self-aggregation of the longer chain ionic liquids in aqueous solutions. The influence of the cation core and the positional isomerism of the ionic liquids on their ability to form ABS closely correlates with the ionic fluid affinity for water.
Compounds
# Formula Name
1 H2O water
2 H2KO4P monopotassium phosphate
3 C6H11ClN2 1-ethyl-3-methylimidazolium chloride
4 C8H15ClN2 1-butyl-3-methylimidazolium chloride
5 C10H19ClN2 1-hexyl-3-methylimidazolium chloride
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
  • Mass fraction - 2 ; Liquid mixture 2
  • Mass fraction - 2 ; Liquid mixture 1
  • Mass fraction - 3 ; Liquid mixture 1
  • Mass fraction - 3; Liquid mixture 2
  • Pressure, kPa; Liquid mixture 2
  • Temperature, K; Liquid mixture 2
  • Liquid mixture 2
  • Liquid mixture 1
  • arm rule
  • arm rule
  • arm rule
  • 1
  • POMD
  • 1
  • 2
  • 3
  • Mass fraction - 2 ; Liquid mixture 1
  • Mass fraction - 3; Liquid mixture 1
  • Temperature, K; Liquid mixture 1
  • Pressure, kPa; Liquid mixture 1
  • Liquid mixture 1
  • Liquid mixture 2
  • Titration method
  • 49
  • POMD
  • 1
  • 2
  • 4
  • Mass fraction - 2 ; Liquid mixture 2
  • Mass fraction - 2 ; Liquid mixture 1
  • Mass fraction - 4 ; Liquid mixture 1
  • Mass fraction - 4; Liquid mixture 2
  • Pressure, kPa; Liquid mixture 2
  • Temperature, K; Liquid mixture 2
  • Liquid mixture 2
  • Liquid mixture 1
  • arm rule
  • arm rule
  • arm rule
  • 1
  • POMD
  • 1
  • 2
  • 4
  • Mass fraction - 2 ; Liquid mixture 1
  • Mass fraction - 4; Liquid mixture 1
  • Temperature, K; Liquid mixture 1
  • Pressure, kPa; Liquid mixture 1
  • Liquid mixture 1
  • Liquid mixture 2
  • Titration method
  • 100
  • POMD
  • 1
  • 2
  • 5
  • Mass fraction - 2 ; Liquid mixture 2
  • Mass fraction - 2 ; Liquid mixture 1
  • Mass fraction - 5 ; Liquid mixture 1
  • Mass fraction - 5; Liquid mixture 2
  • Temperature, K; Liquid mixture 2
  • Pressure, kPa; Liquid mixture 2
  • Liquid mixture 2
  • Liquid mixture 1
  • arm rule
  • arm rule
  • arm rule
  • 1
  • POMD
  • 1
  • 2
  • 5
  • Mass fraction - 2 ; Liquid mixture 1
  • Mass fraction - 5; Liquid mixture 1
  • Temperature, K; Liquid mixture 1
  • Pressure, kPa; Liquid mixture 1
  • Liquid mixture 1
  • Liquid mixture 2
  • Titration method
  • 133