This application brings for you azeotropic data (azeotrope boiling point/temperature and composition), based on vapor-liquid equilibrium calculations. So the program does not provide stored experimental data, but predicts them theoretically.
Method of calculationAt an azeotropic point the composition of vapor- and liquid phases are identical (xi = yi), and the bubble- and dew point curves have a local extrema.
Take an objective function that measures the relative deviation of the compositions between the vapor- and liquid phases:
fi = (xi - yi) / xi
At every x points in the composition space, where fi = 0 must be an azeotropic point. (Except the corner points representing the pure components (i), where xi = 1 and xj≠i = 0.) The program uses multi-variate Newton-Raphson search to locate these points.
The composition of the vapor phase is calculated according to the modified Raoult's law:
pi = γi • psat.,i • xi
yi = pi / Σj=1→N pj
- pi is the partial pressure of component i in the vapor phase of the mixture
- γi (gamma) is the activity coefficient of component i in the liquid mixture
- psat.,i is the vapor pressure of saturated pure component i
- x is the liquid phase mole fraction of component i
- y is the vapor phase mole fraction of component i
Find more information about azeotropes at Wikipedia