Example 8.10 SLE of the Non-Eutectic Mixture Diphenylacetylene - N,N-Diphenylhydrazine

problem:

Calculate the SLE diagram for the binary system diphenylacetylene (1) – N,N-diphenylhydrazine (2) with a minimum melting point at a composition x_{1} = 0.826, T_{min} = 323.5 K using the Porter expression and the following pure component data.

Fig. 8.10 b)

general

constants

and

definitions:

input data

Solution

Different from example 8.09, the melting temperatures and heat of fusion values for the two components are now different. Applying the same calculation as in 8.09 therefor leads to different values of the difference in Porter parameters between the phases if this difference is calculated from the equilibrium of the first or second component:

The SLE diagram can again be calculated with the same functions as developed in example 8.09. For the Porter parameter the value of 1.917 is used.

At the correct equilibrium temperature, the summation condition for the mole fractions in the liquid must be met:

(starting temperature for root function)

Using these functions, a graphical representation of the phase equilibrium can be generated.