Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Pressure-volume-temperature measurements of phosphonium-based ionic liquids and analysis with simple equations of state

Goncalves, F. A. M. M., Costa, C. S. M. F., Ferreira, C. E., Bernardo, J. C. S., Johnson, I., Fonseca, I. M. A., Ferreira, A. G. M.
J. Chem. Thermodyn. 2011, 43, 6, 914-929
ABSTRACT
In spite of the great importance of the (P, V, T) data of phosphonium based ionic liquids, only limited information on these data seems to be available in the open literature. In this work, we present the results for the density measurements of the trihexyltetradecylphosphonium chloride, [(C6H13)3P(C14H29)][Cl] and trihexyltetradecylphosphonium dicyanamide, [(C6H13)3P(C14H29)][N(CN2)] with an estimated uncertainty of +-0.5 kg m-3. The ranges of temperature and pressure are T = (273.15 to 318.15) K and p = (0.1 to 25) MPa for [(C6H13)3P(C14H29)][Cl] and T = (273.15 to 318.15) K and p = (0.1 to 35) MPa for [(C6H13)3P(C14H29)][N(CN2)]. The high consistency of our data for [(C6H13)3P(C14H29)][Cl] compared with those measured by other authors allowed all the experimental data for this IL to be combined and correlated using the Goharshadi-Morsali-Abbaspour equation of state over a wide range of temperature and pressure. From this equation, thermomechanical coefficients as the isothermal compressibility, thermal expansivity, thermal pressure, and internal pressure were calculated for the two ILs. The Sanchez-Lacombe equation of state was used also for (P, V, T) correlation and the estimation of the free volume in these phosphonium ionic liquids. Finally ionic volumes for trihexyltetradecylphosphonium cation and several anions available in the literature made possible the calculation of the free (hole) volume.
Compounds
# Formula Name
1 C32H68ClP trihexyl(tetradecyl)phosphonium chloride
2 C34H68N3P tetradecyl(trihexyl)phosphonium dicyanamide
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
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 72
  • POMD
  • 2
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Vibrating tube method
  • 173