Isochoric collinearity studies with density dependent mixing rules Academic Article uri icon


  • Collinearity of isochores passing through the cricondentherm (CT) of a mixture has been proven theoretically and demonstrated with experimental data (Rowlinson et al., 1986). Also, recent research has shown that cubic EOS in combination with their standard quadratic MR predict the phenomena of isochoric collinearity at the CT (Barrufet and Eubank, 1987). In addition, several researchers have proposed density dependent MR for use with non-simple mixtures. This work is designed to investigate whether introducing density dependence in the MR used with cubic EOS will affect the prediction of isochoric collinearity at the CT. To accomplish this, the Redlich-Kwong equation of state with recently proposed density dependent mixing rules is used to predict the cricondentherm (CT) of six hypothetical binary mixtures. The slope of the isochore passing through the CT is then calculated on both the two-phase and the single-phase sides of the CT and compared. This check of the physical phenomena of isochoric collinearity at the CT is then compared with similar calculations from the Redlich-Kwong equation of state with van der Waals' mixing rules. The density dependent mixing rules used are found to violate the collinearity constraint at the CT, while use of the quadratic mixing rules do not. The effect of the density dependence in the mixing rules upon predicted quantities and the size of the retrograde region is also observed. © 1989.

author list (cited authors)

  • Joffrion, L. L., Barrufet, M. A., & Eubank, P. T.

citation count

  • 2

publication date

  • September 1989