FORMATION OF AZEOTROPES FROM THE STANDPOINT OF SOLVATION THERMODYNAMICS

This deviation is expressed by the activity coefficient of each component. However, the physical origin of this behavior is not well quantified in terms of molecular interactions. In this work, a regular solution model was used, relating the beta parameter to the solvation free energy of pure liquids in themselves and in the other component. A mathematical expression was derived that indicates when an azeotrope is formed. This equation shows that the greater the difference in vapour pressure between components, the greater the solvation difference of each liquid in itself and in the other component is needed to form the azeotrope. A set of 10 mixtures were randomly chosen and investigated as a test, and the equation worked in all cases.

Automated summary

This study used a regular solution model to explain the formation conditions of azeotropes by deriving a mathematical expression.