9459

Breaking the Azeotrope between Cyclohexane and Benzene Using Aniline

Consider a binary mixture of cyclohexane (BP ) and benzene (BP ) at . This mixture presents a minimum-boiling azeotrope. It is possible to break this azeotrope using aniline. The vapor-liquid equilibrium (VLE) behavior of the ternary mixture is described by a modified form of Raoult's law with activity coefficients predicted by the Wilson model [1]. This Demonstration plots the pseudo-binary phase diagram for user-set values of the aniline mole fraction. We plot the benzene liquid mole fraction versus the benzene vapor mole fraction with both mole fractions calculated on an aniline-free basis. It is clear from the first snapshot that, when no aniline is present, the binary mixture exhibits a positive azeotrope. On the other hand, when enough aniline is used (see snapshots 3 and 4), the azeotrope disappears and there is an inversion of volatility, so that the heavy-boiling cyclohexane distills overhead in an extractive distillation process [2, 3]. In this case, the VLE data is below the diagonal black line.

SNAPSHOTS

  • [Snapshot]
  • [Snapshot]
  • [Snapshot]
  • [Snapshot]

DETAILS

References
[1] G. M. Wilson, "Vapor-Liquid Equilibrium XI: A New Expression for the Excess Free Energy of Mixing," Journal of the American Chemical Society, 86(2), 1964 pp. 127–130.
[2] M. F. Doherty and J. P. Knapp, "Distillation, Azeotropic and Extractive," in Kirk-Othmer Encyclopedia of Chemical Technology, New York: John Wiley & Sons, 2004.
[3] B. Kolbe, J. Gmehling, and U. Onken, "Selection of Solvents for Extractive Distillation Using Predicted and Correlated VLE Data," Inst. Chem. E. Symp. Ser., 56(1), 1979 pp. 1.3/23–40.
    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.









 
RELATED RESOURCES
Mathematica »
The #1 tool for creating Demonstrations
and anything technical.
Wolfram|Alpha »
Explore anything with the first
computational knowledge engine.
MathWorld »
The web's most extensive
mathematics resource.
Course Assistant Apps »
An app for every course—
right in the palm of your hand.
Wolfram Blog »
Read our views on math,
science, and technology.
Computable Document Format »
The format that makes Demonstrations
(and any information) easy to share and interact with.
STEM Initiative »
Programs & resources for
educators, schools & students.
Computerbasedmath.org »
Join the initiative for modernizing
math education.
Powered by Wolfram Mathematica © 2014 Wolfram Demonstrations Project & Contributors  |  Terms of Use  |  Privacy Policy  |  RSS Give us your feedback
Note: To run this Demonstration you need Mathematica 7+ or the free Mathematica Player 7EX
Download or upgrade to Mathematica Player 7EX
I already have Mathematica Player or Mathematica 7+