Understanding the Differing Fluid Phase Behavior of Cyclohexane + Benzene and Their Hydroxylated or Aminated Forms

Y. Mauricio Muñoz-Muñoz, Chieh Ming Hsieh, Jadran Vrabec

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The three binary mixtures cyclohexane + benzene, cyclohexanol + phenol, and cyclohexylamine + aniline exhibit qualitatively different vapor-liquid phase behavior, that is, azeotropic with a pressure maximum, azeotropic with a pressure minimum, and zeotropic, respectively. Employing molecular modeling and simulation, the COSMO-SAC model, and a cubic equation of state, the root of these effects is studied on the basis of phase equilibria, excess properties for volume, enthalpy, and Gibbs energy as well as microscopic structure. It is found that cyclohexane + benzene is characterized by more pronounced repulsive interactions, leading to pressure maximum azeotropy and a positive excess Gibbs energy. Functionalizing the aliphatic and aromatic rings with one amine group each introduces attractive hydrogen bonding interactions of moderate strength that counterbalance such that the mixture becomes zeotropic. The hydroxyl groups introduce strong hydrogen bonding interactions, leading to pressure minimum azeotropy and a negative excess Gibbs energy.

Original languageEnglish
Pages (from-to)5374-5384
Number of pages11
JournalJournal of Physical Chemistry B
Volume121
Issue number21
DOIs
StatePublished - 1 Jun 2017

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