Azeotropic phenomena in the global phase diagram of the Redlich-Kwong equation of state

The global phase diagram of a binary mixture described by the Redlich–Kwong equation of state has been calculated for the molecule volume ratio b11:b22=13:7 and the linear mixing rule for the molecular volumes. Boundary states separating regions with different topology of azeotropic lines (“horn’' region with double azeotropy and “dish’' region with an azeotropic line connecting two critical azeotropic points) are found and discussed in connection with other already known non-azeotropic phenomena.