Laboratory setup
Fractional distillation in a laboratory makes use of common laboratory glassware and apparatuses, typically including a Bunsen burner, a round-bottomed flask and a condenser, as well as the single-purpose fractionating column.
Fractional distillation apparatus using a Liebig condenser. A conical flask is used as a receiving flask. Here the distillation head and fractionating column are combined in one piece.
* heat source, such as a hot plate with a bath, and ideally with a magnetic stirrer.
* distilling flask, typically a round-bottom flask
* receiving flask, often also a round-bottom flask
* fractionating column
* distillation head
* thermometer and adapter if needed
* condenser, such as a Liebig condenser, Graham condenser or Allihn condenser
* vacuum adapter (not used in image to the right)
* boiling chips, also known as anti-bumping granules
* Standard laboratory glassware with ground glass joints, e.g. quickfit apparatus.
As an example, consider the distillation of a mixture of water and ethanol. Ethanol boils at 78.4 °C while water boils at 100 °C. So, by heating the mixture, the most volatile component will concentrate to a greater degree in the vapor leaving the liquid. Some mixtures form azeotropes, where the mixture boils at a lower temperature than either component. In this example, a mixture of 96% ethanol and 4% water boils at 78.2 °C, being more volatile than pure ethanol. For this reason, ethanol cannot be completely purified by direct fractional distillation of ethanol-water mixtures.
The apparatus is assembled as in the diagram. (The diagram represents a batch apparatus, as opposed to a continuous apparatus.) The mixture is put into the round bottomed flask along with a few anti-bumping granules (or a Teflon coated magnetic stirrer bar if using magnetic stirring), and the fractionating column is fitted into the...