Modeling of thermodynamically difficult systems

Stanley I. Sandler, Jeffrey P. Wolbach, Marcelo Castier, Gonzalo Escobedo-Alvarado

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12 Citations (Scopus)


While current thermodynamic models are satisfactory for the description of many systems of industrial interest, there are other mixtures for which specialized modeling techniques are needed. Mixtures containing associating and hydrogen-bonding species, and the complicated phase behavior of highly nonideal mixtures are two examples of mixtures that are difficult to describe accurately. Here, we consider recent advances in predicting the phase behavior of such mixtures. In particular, we will show how molecular orbital calculations can be used to aid in the description of the phase behavior of pure fluids and mixtures containing hydrogen-bonding components. The description of highly nonideal mixtures over large ranges of temperature and pressure has traditionally been a difficult thermodynamic problem. Here we will show how recent combinations of excess free energy models and equations of state provides better modeling tools for this problem using examples from vapor-liquid and liquid-liquid equilibria, and critical region behavior.

Original languageEnglish
Pages (from-to)15-29
Number of pages15
JournalFluid Phase Equilibria
Issue number1-2
Publication statusPublished - Nov 1997



  • Critical phenomena
  • Equations of state
  • Liquid-liquid equilibrium
  • Molecular orbital theory
  • Vapor-liquid equilibrium

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Sandler, S. I., Wolbach, J. P., Castier, M., & Escobedo-Alvarado, G. (1997). Modeling of thermodynamically difficult systems. Fluid Phase Equilibria, 136(1-2), 15-29.