Distillation

We explain what distillation is, examples of this method of separation and the types of distillation that can be used.

1. What is distillation?

Distillation is called a method of separation of phases, also called methods of separation of mixtures, What consists in the consecutive and controlled use of two other physical processes: vaporization (or evaporation) and condensation, us Selectively select to separate the ingredients from a mixture, usually of a homogenous type, that is, in which its elements cannot be distinguished with the naked eye.

Mixtures susceptible to distillation can contain two liquids, a solid in a liquid or even liquefied gases, as well. That this method takes advantage of the boiling point of substances, one of the characteristics inherent in matter.

The boiling point, then, is the temperature that is precisely at which a liquid becomes a gas. Evapora).

Thus, for the distillation to be carried out correctly, we must boil the mixture until it reaches the boiling point of one of the substances. Members, which will then become steam and may be conducted to a cooled container, in which to condense and recover its liquidity.

The other integral substance, on the other hand, will remain in the container without alterations; but in both cases we will have pure substances, free of the initial mixture.

It can serve you: Filtration.

1. Distillation Examples

• R oil refining . The separation of the various hydrocarbons present in the oil is carried out by fractional distillation, storing each compound derived from the cooking of the crude oil in different layers or compartments. These gases rise and condense in higher layers, while denser substances such as asphalt and paraffin remain.
• Catalytic Racking This is what certain vacuum distillations are called in the oil processing, using vacuum towers to separate the gases from the cooking of the crude oil. Thus the boiling of the hydrocarbons is accelerated and the process is expedited.
• Purification of ethanol . To separate alcohols such as ethanol from water during laboratory production, azeotropic distillation is used, adding to the mixture benzene or other components that promote or accelerate the separation, and which can then be easily removed without altering the chemistry of the product.
• Coal processing . To obtain liquid organic fuels, coal or wood is used by dry distillation procedures: thus the gases emitted in combustion can be condensed.
• Thermolysis of mineral salts . Through dry distillation various mineral substances of high industrial utility are obtained, from the emanation and condensation of gases obtained by burning mineral salts.
• The still . This is the name of the device invented in Arab antiquity, whose purpose is to produce perfumes, medicines and alcohol from fermented fruits. In its operation, the principles of distillation are used: substances are heated in a small boiler and the gases produced in a coil that leads to another vessel are cooled.
• Perfume production The distillation with trailing steam is used to obtain perfumes, boiling water together with preserved flowers, to produce a gas full of the desired smell, and which, when condensed, can be used as a base liquid in the perfumes.

1. Types of distillation

Distillation can occur in different ways:

• Distillation s imple . The most elementary is to boil the mixture until the elements are separated. It does not guarantee, however, the total purity of the distilled substance.
• Distillation It is carried out by means of a fractionation column: different plates in which evaporation and condensation occur successively, guaranteeing greater purity in the result.
• Vacuum distillation . Using the generated vacuum pressure, the process is catalyzed to reduce the boiling point of the ingredients in half.
• Zeotropic distillation . The necessary to break an azeotrope, that is, a mixture whose substances behave as one, even sharing the boiling point. It includes the presence of separating agents, all according to Raoult's Law.
• Distillation by steam entrainment . Volatile and nonvolatile components of a mixture are separated by direct injection of water vapor.
• Distillation s eca . It consists of heating solid materials without liquid solvents, obtaining gases and then condensing them in another container.
• Improved distillation . Also called alternating or reactive distillation, they are adapted to specific cases of mixtures that are difficult to separate from the same boiling point.