Extractive distillation


Extractive distillation

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. The method is used for mixtures having a low value of relative volatility, nearing unity. Such mixtures cannot be separated by simple distillation, because the volatility of the two components in the mixture is nearly the same, causing them to evaporate at nearly the same temperature at a similar rate, making normal distillation impractical.

The method of extractive distillation uses a separation solvent, which is generally nonvolatile, has a high boiling point and is miscible with the mixture, but doesn't form an azeotropic mixture. The solvent interacts differently with the components of the mixture thereby causing their relative volatilities to change. This enables the new three-part mixture to be separated by normal distillation. The original component with the greatest volatility separates out as the top product. The bottom product consists of a mixture of the solvent and the other component, which can again be separated easily because the solvent doesn't form an azeotrope with it. The bottom product can be separated by any of the methods available.

It is important to select a suitable separation solvent for this type of distillation. The solvent must alter the relative volatility by a wide enough margin for a successful result. The quantity, cost and availability of the solvent should be considered. The solvent should be easily separable from the bottom product, and should not react chemically with the components or the mixture, or cause corrosion in the equipment. A classic example to be cited here is the separation of an azeotropic mixture of benzene and cyclohexane, where aniline is one suitable solvent.

See also

* Batch Distillation
* Distillation
* Heteroazeotrope
* Theoretical plate

External links

* [http://www.cheresources.com/extrdist.shtml Extractive Distillation]


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • extractive distillation — ekstrakcinė distiliacija statusas T sritis fizika atitikmenys: angl. extractive distillation vok. Ekstraktivdestillation, f; Extraktionsdestillation, f rus. экстрактивная дистилляция, f pranc. distillation par extraction, f …   Fizikos terminų žodynas

  • extractive distillation — ekstrakcinis distiliavimas statusas T sritis chemija apibrėžtis Distiliavimas, kai naudojamas atskiriantysis tirpiklis, tirpinantis vieną iš skysčių mišinio komponentų ir turintis daug aukštesnę už atskiriamųjų komponentų virimo temperatūrą.… …   Chemijos terminų aiškinamasis žodynas

  • extractive distillation — In the distillation process, the separation of different components of mixtures which have similar vapor pressures by flowing a solvent which is selective for some of the components in the feed down the distillation column as the operation… …   Petroleum refining glossary

  • extractive distillation — noun : a combined continuous fractional distillation and extraction in which a relatively high boiling solvent (as furfural) flowing down the distillation column selectively scrubs one or more of the components from a mixture of compounds of… …   Useful english dictionary

  • Distillation (disambiguation) — Distillation is a method of separating mixtures based on differences in their volatilities in a boiling liquid mixture. Distillation may also refer to: Distillation (Erin McKeown album), 2000 Distillation (Wishbone Ash album), 1997 Distillation… …   Wikipedia

  • Distillation — Distiller and Distillery redirect here. For other uses, see Distiller (disambiguation) and Distillery (disambiguation). For other uses, see Distillation (disambiguation). Laboratory display of distillation: 1: A heating device 2: Still pot 3:… …   Wikipedia

  • distillation par extraction — ekstrakcinė distiliacija statusas T sritis fizika atitikmenys: angl. extractive distillation vok. Ekstraktivdestillation, f; Extraktionsdestillation, f rus. экстрактивная дистилляция, f pranc. distillation par extraction, f …   Fizikos terminų žodynas

  • DISTILLATION — La distillation est une des méthodes de séparation les plus importantes dont on dispose pour résoudre un mélange en ses divers constituants. Elle est fondée sur le fait qu’une phase vapeur surmontant un liquide bouillant et en équilibre avec ce… …   Encyclopédie Universelle

  • Extractive metallurgy — is the study of the processes used in the separation and concentration (benefaction) of raw materials. The field is an applied science, covering all aspects of the physical and chemical processes used to produce mineral containing and metallic… …   Wikipedia

  • distillation — 1. The general process of vaporizing liquids, crude oil, or one of its fractions in a closed vessel, collecting and condensing the vapors into liquids. Commercial forms of distillation in petroleum refining are crude, atmospheric, vacuum, rerun,… …   Petroleum refining glossary


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.