Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

Solubility of beta-diketonate complexes for cobalt(III) and chromium(III) in supercritical carbon dioxide

Haruki, M.[Masashi], Kobayashi, F.[Fumiya], Okamoto, M.[Masaaki], Kihara, S.-i.[Shin-ichi], Takishima, S.[Shigeki]
Fluid Phase Equilib. 2010, 297, 2, 155-161
ABSTRACT
The solubilities of tris(2,2,6,6-tetramethyl-3,5-heptanedionate) cobalt(III) (Co(thd)3) and chromium(III) (Cr(thd)3), in supercritical carbon dioxide (scCO2) were measured at temperatures ranging from 313 to 343 K. The measurements were carried out using a circulation-type apparatus with a UV-Vis spectrometer. The solubilities of both Co(thd)3 and Cr(thd)3 increased as both the density of scCO2 and the temperature increased, which was the same tendency as cobalt(III) acetylacetonate (Co(acac)3) and chromium(III) acetylacetonate (Cr(acac)3), as measured in our previous work. The solubilities of Cr(thd)3 were higher than that of Co(thd)3, and the solubilities of Co(thd)3 and Cr(thd)3 were about 50 and 70-fold higher than those of Co(acac)3 and Cr(acac)3, respectively. The measured solubilities of the metal complexes were correlated with the equation based on Chrastil s equation. The parameters were determined by correlating experimental data for each metal complex, and the correlated results closely replicated the experimental data those of Co(thd)3, in particular. Moreover, the charge distributions on the molecular surface of CO2 and the metal complexes used in the measurement were estimated by quantum chemical calculation and the COSMO-RS to clear the effect of the molecular structure of the metal complexes on the affinity for CO2.
Compounds
# Formula Name
1 C33H57CoO6 tris(2,2,6,6-tetramethyl-3,5-heptanedionate) cobalt (III)
2 C33H57CrO6 tris(2,2,6,6-tetramethyl-3,5-heptandionato)chromiumtris(2,2,6,6-tetramethyl-3,5-heptandionato)chromium
3 CO2 carbon dioxide
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
  • 3
  • 1
  • Mole fraction - 1 ; Fluid (supercritical or subcritical phases)
  • Pressure, kPa; Fluid (supercritical or subcritical phases)
  • Temperature, K; Fluid (supercritical or subcritical phases)
  • Fluid (supercritical or subcritical phases)
  • Crystal - 1
  • UV-vis spectrometer - calibration curve
  • 33
  • POMD
  • 3
  • 2
  • Mole fraction - 2 ; Fluid (supercritical or subcritical phases)
  • Pressure, kPa; Fluid (supercritical or subcritical phases)
  • Temperature, K; Fluid (supercritical or subcritical phases)
  • Fluid (supercritical or subcritical phases)
  • Crystal - 2
  • UV-vis spectrometer - calibration curve
  • 19