Definition - What does Azeotrope mean?
Azeotrope is a mixture of two or more liquids with proportions that cannot be changed by simple distillation process. This means that in order to separate the components the mixture has to go through several distillation processes. It is also known as a constant boiling mixture because when the mixture is boiled, the vapors produced contain the same proportions as the constituents.
Petropedia explains Azeotrope
In an azeotropic mixture, the concentration or proportion of liquids remains same whether the mixture is in liquid or vapor phase. Since the proportion of the liquids does not change, it is difficult to separate the mixture with a simple distillation process. Azeotropic mixtures are separated by Fractional Distillation or multiple repeated distillation processes. The component which is more volatile in the mixture tends to vaporize and is collected separately while the least volatile component remains in the distillation chamber. Ultimately the results of the repeated distillation are two pure, separate solutions.