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:
where
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
(i.e.,
), independent of the initial composition in the still.
