Thermodynamics Research Center / ThermoML | Thermochimica Acta

Determination of the enthalpies of sublimation and evaporation from thermogravimetric data: Application to metalorganic complexes of Al and Cr

Gairola, A.[Anshita], Kunte, G. V., Umarji, A. M., Shivashankar, S. A.
Thermochim. Acta 2009, 488, 1-2, 17-20
ABSTRACT
A series of bimetallic acetylacetonate (acac) complexes, AlxCr1.x(acac)3, 0.x.1, have been synthesized for application as precursors for the CVD of substituted oxides, such as (AlxCr1.x)2O3. Detailed thermal analysis has been carried out on these complexes, which are solids that begin subliming at low temperatures, followed by melting, and evaporation from the melt. By applying the Langmuir equation to differential thermogravimetry data, the vapour pressure of these complexes is estimated. From these vapour pressure data, the distinctly different enthalpies of sublimation and evaporation are calculated, using the Clausius.Clapeyron equation. Such a determination of both the enthalpies of sublimation and evaporation of complexes, which sublime and melt congruently, does not appear to have been reported in the literature to date.
Compounds
# Formula Name
1 C15H21AlO6 aluminum triacetylacetonate
2 C15H21CrO6 tris(2,4-pentanedionato)chromium
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
  • Molar enthalpy of vaporization or sublimation, kJ/mol ; Crystal
  • Temperature, K; Crystal
  • Crystal
  • Gas
  • DSC
  • 1
  • POMD
  • 2
  • Molar enthalpy of vaporization or sublimation, kJ/mol ; Crystal
  • Temperature, K; Crystal
  • Crystal
  • Gas
  • DSC
  • 1