Polyazeotropy in binary systems

Jaime Wisniak, Hugo Segura, Ricardo Reich

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Polyazeotropy in binary systems is a very singular case of vapor-liquid equilibrium (VLE), and its causes have not been studied in detail. The unique evidence about the phenomenon is the experimental VLE results for the benzene-hexafluorobenzene system, which exhibits two simultaneous azeotropes. The purpose of this work is to make a thermodynamical analysis of polyazeotropy at low pressures and to establish the necessary and sufficient conditions that provoke it. The evolution of polyazeotropes with temperature and pressure is explained, and the criteria to predict azeotropic behavior from minimal information are developed. This study also delivers some important results about the possibility of predicting polyazeotropy using classical G̃E models and about estimation of the parameters for excess energy models from activity coefficients at infinite dilution, in particular, when this procedure generates changes of concavity for the G̃E function.

Original languageEnglish
Pages (from-to)3742-3758
Number of pages17
JournalIndustrial and Engineering Chemistry Research
Issue number10
StatePublished - 1 Jan 1996

ASJC Scopus subject areas

  • Chemistry (all)
  • Chemical Engineering (all)
  • Industrial and Manufacturing Engineering


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