The vapor-liquid equilibrium behavior of a binary mixture of chloroform and acetone at 760 mmHg can be obtained using the Wilson model and a modification of Raoult's law.
This mixture exhibits a maximum boiling azeotrope, whose composition is 66.13% chloroform mole fraction.
The simple distillation residue curve is the solution of the following differential-algebraic equation:
is the warped time,
is the chloroform mole fraction in the still at
is the equilibrium constant, and
is the initial ethanol composition in the still.
Since a negative azeotrope exists for this mixture, the still has the azeotropic composition for large
), independent of the initial composition in the still.
For more information, see
M. F. Doherty and M. F. Malone, Conceptual Design of Distillation Systems
, New York: McGraw-Hill, 2001.