Hetero-azeotropic mixture

Swi toslawski s ebullio-meter, as modified by Olszewski, for hetero-azeotropic mixtures... 

However, the number of phases is not limited to two only. For example, in the case of hetero-azeotropic mixtures like butanol-water or ethanol-water-cyclohexane already two liquid phases exist besides the vapor phase. Hildebrand showed that in the system water-heptane-perfluorokerosene-aniline-phosphorus-gallium-mercury even seven liquid phases are in equilibrium with the vapor phase [2] (see Figure 5.3). 

Separation of a Partially Miscible Mixture Water and n-butanol in the concentration range of about 50-98.1 mol % water form two liquid phases that boil at92.7°C at one atm. On cooling to 40°C, the hetero-azeotrope separates into phases containing 53 and 98 mol % water. 

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