Steam Distillation

When an ideal mixture of two miscible liquids is heated to boiling, the solution boils at a temperature between the boiling points of each component. If these liquids have very different boiling points, when the mixture starts to boil, the vapor is rich with the molecules of the more volatile component. This phenomenon is often used to separate mixtures using simple distillation, where a mixture of two miscible liquids is heated and the vapor is then condensed back to liquid and collected.

As the vapor rich with the more volatile component is collected as the distillate, the liquid phase becomes rich with the molecules of the less volatile component. However, this technique requires the solution to be heated at least to the boiling point of the more volatile compound and often beyond that.

In the case of temperature-sensitive organic compounds, this high temperature could lead to the organic molecules decomposing into something else. So, how can we separate these types of compounds? First, let's take a step back.

Recall that the pressure of a vapor in equilibrium with its condensed phase is called vapor pressure. The components of a mixture of liquids each have their own vapor pres