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-Fundamentals: Thermodynamics

1.5 Distribution coefficients

Raoult's law can also be represented by using the distribution coefficients. They are indicated with kA and kB and equal to:

kA = yA / xA = PAv / P ;
kB = yB / xB = PBv / P ;

The distribution coefficients are strongly dependent on the temperature since PAv and PBv are dependent on the temperature according to the Antoine equation:

ln Piv = A - B / (T[?K] + C)

where A, B, C are specific constants for each pure compounds and can be easily found in the literature (i.e. Perry's Chemical Engineers' Handbook).

For the component i, it is then:

Piv = Piv [T]
ki = ki [T]