There are two types of Azeotrope.
1) The first one is caused by the strong positive deviation from the Raoult's Law.
P-x diagram will look similar to this:
There is a maximum point in this diagram. This maximum point represents the azeotropic composition. The total vapour pressure curve or line can easily be done with the help of Dalton's law which states that the sum of every partial pressure must be equal to the total pressure.
T-x diagram:
If a mixture has a high vapour pressure, it also means that this mixture has a low boiling temperature. So it is not surprising to see a minimum point in a Temperature-composition diagram. In this case the azeotrope boils at a lower temperature than those two pure components. This type of azeotrope is also called as 'minimum boiling azeotrope'.
If we have a feed composition lower than azeotropic composition, by performing a distillation you end up having the azeotrope at the top and pure A as a bottom product.
If we have a feed composition higher than azeotropic composition, you also end up having the azeotrope as a top product and pure B at the bottom of the column.
Therefore it is not possible to have both pure A and B at the same time if a mixture of two or more liquids shows an azeotropic composition.
1) The first one is caused by the strong positive deviation from the Raoult's Law.
P-x diagram will look similar to this:
There is a maximum point in this diagram. This maximum point represents the azeotropic composition. The total vapour pressure curve or line can easily be done with the help of Dalton's law which states that the sum of every partial pressure must be equal to the total pressure.
T-x diagram:
If a mixture has a high vapour pressure, it also means that this mixture has a low boiling temperature. So it is not surprising to see a minimum point in a Temperature-composition diagram. In this case the azeotrope boils at a lower temperature than those two pure components. This type of azeotrope is also called as 'minimum boiling azeotrope'.
If we have a feed composition lower than azeotropic composition, by performing a distillation you end up having the azeotrope at the top and pure A as a bottom product.
If we have a feed composition higher than azeotropic composition, you also end up having the azeotrope as a top product and pure B at the bottom of the column.
Therefore it is not possible to have both pure A and B at the same time if a mixture of two or more liquids shows an azeotropic composition.
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