Steam distillation
This is a process used to purify substances which decompose above 100°C, have a significant vapour pressure pi below 100°C, and are insoluble in water. The liquid mixture made up of an aqueous phase and the impure product is boiled at atmospheric pressure, i.e.
Psample + Pwater = 1 atm.
As the liquid boils and the vapour phase is separated, condensed and collected in an external container. If the impure substance is a liquid then the two phases which are distilled can be separated to recover the purified product.
