• IECR-57-5722-5731

Vapor pressure and heat of vaporization of molecules that associate in the gas phase

Authors: Radomir I. Slavchov, Javor K. Novev, Sebastian Mosbach, and Markus Kraft*

Reference: Industrial & Engineering Chemistry Research 57(16), 5722-5731, (2018)

  • A model of vapour-liquid 1-component equilibrium with vapour dimerization.
  • Predicts analytically vapour pressure, vaporization heat and dimer fraction vs. T.
  • No fitting - input is 6 standard handbook thermodynamic parameters only.
  • Reversely, accurate thermodynamic parameters obtained from vapour pressure data.
  • High precision for fuel components under cylinder conditions.

Graphical abstract A model of the temperature dependence of the vapor pressure and the heat of vaporization of liquids whose vapors contain associates is presented for two cases: dimers and linear associates in the gas phase. The results are analytic generalizations of the Clausius-Clapeyron equation, valid with accuracy of 0.1%-1%, as demonstrated with 11 liquids: formic and acetic acids, methanol, ethanol, n-propanol, n-butanol, water, benzene, toluene, heptane, and iso-octane. The model involves only readily available handbook parameters: the room-temperature heat of vaporization, vapor pressure, heat capacities, second virial coefficient, and heat of dissociation of the dimers in the gas phase.

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*Corresponding author:
Telephone: +44 (0)1223 762784 (Dept) 769010 (CHU)
Address: Department of Chemical Engineering and Biotechnology
University of Cambridge
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Philippa Fawcett Drive
Cambridge CB3 0AS
United Kingdom
Website: Personal Homepage