What is distillation?

Distillation is a widely used method for separating the component substances from a liquid mixture by selective evaporation and condensation. To separate a mixture of liquids, the liquid can be heated to force components, which have different boiling points, into the gaseous state.

In industrial chemistry, distillation is a unit operation of practically universal importance, but it is a physical separation process and not a chemical reaction. Distillation is used for many commercial processes, such as the production of gasoline, distilled water, xylene, alcohol, paraffin, kerosene, and many other liquids.

Types of Distillation

  • Simple distillation

  • Fractional distillation

  • Steam distillation

  • Vacuum distillation

  • Air-sensitive vacuum distillation

  • Short path distillation

  • Zone distillation

Simple Distillation:

The vapor is immediately channeled into a condenser. Consequently, the distillate is not pure but rather its composition is identical to the composition of the vapors at the given temperature and pressure.


Simple Distillation

Fractional Distillation:

It is used in order to separate the components by repeated vaporization-condensation cycles within a packed fractionating column. This separation, by successive distillations, is also referred to as rectification.

Steam Distillation:

Steam Distillation is a method of distilling compounds which are heat-sensitive. The temperature of the steam is easier to control than the surface of a heating element. This allows a high rate of heat transfer without heating at a very high temperature.

Vacuum Distillation:

Some compounds have very high boiling points. Sometimes its easier to lower the pressure than to reach its high boiling point. This technique is referred to as vacuum distillation and it is commonly found in the laboratory in the form of the rotary evaporator.

Air-Sensitive Vacuum Distillation:

Some compounds have high boiling points as well as being air sensitive. For these compounds, a simple vacuum distillation system can be used. Wherein the vacuum is replaced with an inert gas after the distillation is complete.

Short Path Distillation:

It is a distillation technique that involves the distillate traveling a short distance, often only a few centimeters. This technique is normally done at reduced pressure allowing a lower operating temperature range.

Zone Distillation:

It is a distillation process in a long container with a special arrangement. With the partial melting of refined matter in moving liquid zone and condensation of vapor in the solid phase at condensate pulling in cold area.

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Practise This Question

Which among the following methods is most suitable for the separation of dyes in black ink?