Distillation

Distillation

Simple distillation apparatus

Distillation is a process of separating the components or substances from a liquid mixture by using selective boiling and condensation. Distillation may result in essentially complete separation (nearly pure components), or it may be a partial separation that increases the concentration of selected components in the mixture.

History

Ancient distillation equipment as depicted by Zosimos of Panopolis

The history of distillation dates back to ancient times. The earliest evidence of distillation comes from a distillation apparatus found in the Indus Valley Civilization, dating back to around 3000 BC. The process was further developed by the Greeks and Romans, and later by Arab chemists such as Jabir ibn Hayyan.

In the Middle Ages, distillation was used extensively in alchemy.

Illustration from Hieronymus Brunschwig's "Liber de arte Distillandi"

Principles of Distillation

Distillation works on the principle of differences in boiling points of substances. When a liquid mixture is heated, the component with the lower boiling point vaporizes first. The vapor is then cooled and condensed into a liquid, which is collected separately.

Types of Distillation

Simple Distillation

Simple distillation is used to separate liquids with significantly different boiling points. It involves a single cycle of vaporization and condensation.

Fractional Distillation

Fractional distillation is used to separate mixtures of liquids with closer boiling points. It involves multiple cycles of vaporization and condensation, using a fractionating column.

Steam Distillation

Steam distillation is used for temperature-sensitive materials, such as aromatic compounds. It involves passing steam through the mixture to vaporize the components.

Vacuum Distillation

Vacuum distillation is used for substances with very high boiling points. By reducing the pressure, the boiling point of the substance is lowered, allowing distillation at a lower temperature.

Apparatus

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A traditional retort used in distillation

The basic apparatus for distillation includes a heat source, a distillation flask, a condenser, and a receiving flask. In more complex setups, additional components such as fractionating columns and vacuum pumps may be used.

Distillation by retort

Applications

Distillation is widely used in the chemical industry, for the purification of liquids, and in the production of alcoholic beverages. It is also used in the petroleum industry for refining crude oil into its components.

A traditional Ukrainian vodka still

Modern Distillation Techniques

Modern distillation techniques have evolved to include more efficient methods such as batch distillation and continuous distillation.

Diagram of a batch distillation process

Related Pages

• Fractional distillation
• Steam distillation
• Vacuum distillation
• Alcoholic fermentation
• Petroleum refining