extractive distillation

In some senses, adding an entrainer is similar to extractive distillation.

Another early method, called extractive distillation, consists of adding a ternary component which will increase ethanol's relative volatility.

Fractional distillation of the tetrachlorides, also called extractive distillation, is used primarily in Europe.

Most of those methods, but not all, involve the use of a solvent either for liquid-liquid extraction or extractive distillation.

It is a colorless liquid commonly used in the chemical industry as a solvent for extractive distillation and chemical reactions.

DMF is used as a solvent to recover olefins such as 1,3-butadiene via extractive distillation.

Extractive distillation is more costly than ordinary fractional distillation due to costs associated with the recovery of the separating agent.

Extractive distillation is similar to azeotropic distillation, except in this case the entrainer is less volatile than any of the azeotrope's constituents.

Salt-effect distillation is a method of extractive distillation in which a salt is dissolved in the mixture of liquids to be distilled.

Below is a schematic flow diagram of one method, involving extractive distillation, for extraction of the BTX aromatics from a catalytic reformate:

The method of extractive distillation uses a separation solvent, which is generally non-volatile, has a high boiling point and is miscible with the mixture, but doesn't form an azeotropic mixture.

Extractive distillation is defined as distillation in the presence of a miscible, high boiling, relatively non-volatile component, the solvent, that forms no azeotrope with the other components in the mixture.

NMP is used to recover pure hydrocarbons while processing petrochemicals (such as the recovery of 1,3-butadiene using NMP as an extractive distillation solvent) and in the desulfurization of gases.

Butadiene is typically isolated from the other four-carbon hydrocarbons produced in steam cracking by extractive distillation using a polar aprotic solvent such as acetonitrile, N-methylpyrrolidone, furfural, or dimethylformamide, from which it is then stripped by distillation.

By contrast the composition of the water/ethanol azeotrope discussed earlier is not affected enough by pressure to be easily separated using pressure swings and instead, an entrainer may be added that either modifies the azeotropic composition and exhibits immiscibility with one of the components, or extractive distillation may be used.