Vapor pressure of perfluoroalkylalkanes: The role of the dipole

Pedro Morgado, Gaurav Das, Clare McCabe, Eduardo J. M. Filipe*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


The vapor pressure of four liquid perfluoroalkylalkanes (CF3(CF2)n(CH2)mCH3; n = 3, m = 4,5,7; n = 5, m = 5) was measured as a function of temperature between 278 and 328 K. Molar enthalpies of vaporization were calculated from the experimental data, and the results were compared with data from the literature for the corresponding alkanes and perfluoroalkanes. The heterosegmented statistical associating fluid theory was used to interpret the results at the molecular level both with and without the explicit inclusion of the dipolar nature of the molecules. Additionally, ab initio calculations were performed for all perfluoroalkylalkanes studied to determine the dipole moment to be used in the theoretical calculations. We demonstrate that the inclusion of a dipolar term is essential for describing the vapor-liquid equilibria of perfluoroalkylalkanes. It is also shown that vapor-liquid equilibria in these compounds result from a subtle balance between dipolar interactions, which decrease the vapor pressure, and the relatively weak dispersive interactions between the hydrogenated and fluorinated segments. (Figure Presented).

Original languageEnglish
Pages (from-to)1623-1632
Number of pages10
JournalJournal of Physical Chemistry B
Issue number4
Publication statusPublished - 29 Jan 2015

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry


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