Phase Equilibria and Phase Behaviour

For Phase Equilibria

$T_\text{liq} = T_\text{vap}$

$p_\text{liq} = p_\text{vap}$

$f^\text{liq} = f^\text{vap}$

Relative Volatility

$K_i = \frac{y_i}{x_i}$

$\alpha_{ij} = \frac{K_i}{K_j}$

Eutectic

$L \rightarrow \alpha(s) + \beta(s)$

Peritectic

$\alpha(s) + L \rightarrow \beta(s)$

Azeotrope

$y_i = x_i$

At an azeotrope the vapour and liquid compositions are the same. Therefor, the components can’t be separated by distillation

$dG_i = RT d\left( \ln \hat{f_i} \right), \quad \lim_{p \to 0} \left( \frac{\hat{f_i}}{x_i p} \right) = 1$