n.
Vaporization of a liquid and subsequent condensation of the resultant gas back to liquid form.
It is used to separate liquids from nonvolatile solids or solutes (e.g., alcoholic beverages from the fermented materials, water from other components of seawater) or to separate two or more liquids with different boiling points (e.g., gasoline, kerosene, and lubricating oil from crude oil). Many variations have been devised for industrial applications. An important one is fractional distillation, in which liquids with similar boiling points are repeatedly vaporized and condensed as they rise through an insulated vertical column. The most volatile of the liquids emerges first, nearly pure, from the top of the column, followed in turn by less and less volatile fractions of the original mixture. This method separates the mixture's components far better than simple distillation does.