Determination of Azeotropy

by Kyle Cogswell

Submitted : Spring 2009

The ultimate goal of this project is the determination of an azeotrope within a methanol acetone system. An azeotrope is the point in a chemical system at which coexisting compositions of vapor and liquid phases are equivalent. The importance of this project lies in the fact that azeotropes are viewed as undesirable; they prevent one from completely separating a mixture through distillation. This state can occur over a range of temperatures, and for the purposes of this project there is only one azeotrope for each given temperature. Determining the mole fractions, temperature, and pressure for a given system seems very complicated upon first glance. However, all azeotropes occur at a relative extrema in pressure; be it a maximum or minimum value. Therefore, as long as an equation for pressure can be derived, it can be differentiated and set to equal zero so that one can find the point where a peak or trough occurs on a pressure-mole fraction graph. By finding this maximum or minimum, one can in turn find the mole fractions of an azeotrope for a given temperature in the methanol acetone system.

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