The Liebig condenser (, ) or straight condenser is a piece of

laboratory equipment A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as schools, u ...

, specifically a condenser consisting of a straight

glass Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window pane ...

tube surrounded by a water jacket. In typical laboratory operation, such as

distillation Distillation, also classical distillation, is the process of separating the component substances of a liquid mixture of two or more chemically discrete substances; the separation process is realized by way of the selective boiling of the mixt ...

, the condenser is clamped to a

retort stand In chemistry, a retort stand, also called a clamp stand,Laboratory-Equipment.com (2020):Large Clamp Stand, for Q700. Online catalog item 5323-07. Accessed on 202-02-18. a ring stand, or a support stand,Fischer Scientific (2020):American Education ...

in vertical or oblique orientation. The hot

vapor In physics, a vapor (American English) or vapour (Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R ...

of some

liquid Liquid is a state of matter with a definite volume but no fixed shape. Liquids adapt to the shape of their container and are nearly incompressible, maintaining their volume even under pressure. The density of a liquid is usually close to th ...

is introduced at the upper end of the inner tube, and condenses in contact with its colder walls. Water (or some other fluid) is constantly circulated in the jacket to carry away the

heat of vaporization In thermodynamics, the enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy) that must be added to a liquid substance to Phase transition, transform a qua ...

released by the condensing vapor, keeping the tube below the liquid's

boiling point The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding envi ...

. The condensed liquid drips out of the lower end of the inner tube. The Liebig condenser can also be used in

reflux Reflux is a technique involving the condensation of vapors and the return of this condensate to the system from which it originated. It is used in industrial and laboratory distillations. It is also used in chemistry to supply energy to Chemical ...

or Soxhlet extraction operations, although other condenser types are better suited to those tasks. In this usage, the condenser is held vertically above the recipient with the boiling liquid. The vapor is admitted to the inner tube through the lower end, and the condensed liquid drips back through the same opening, while the upper end of the tube is usually left open to the atmosphere.

History

This type of condenser is named after the German chemist

Justus von Liebig Justus ''Freiherr'' von Liebig (12 May 1803 – 18 April 1873) was a Germans, German scientist who made major contributions to the theory, practice, and pedagogy of chemistry, as well as to agricultural and biology, biological chemistry; he is ...

, even though he only perfected and popularized it. The earliest water-cooled laboratory condenser was invented in 1771 by the Swedish- German chemist Christian Weigel (1748–1831). Weigel's condenser consisted of two coaxial

tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...

tubes, which were joined at their lower ends, forming a water jacket, and open at their upper ends. Cold water entered the jacket via an inlet at the bottom and spilled out of the jacket's open upper end. A glass tube carrying vapors from a distillation flask passed through the inner tin tube. Weigel subsequently replaced the inner tin tube with a glass tube, and he devised a clamp to hold the condenser. However, an anonymous pamphlet published in 1781 claimed that a countercurrent condenser had been conceived in 1770 and tested in 1773.Anonymous:
''Nouvelle Construction d'Alambic pour faire toute sorte de distillation en grand'', ...
(New construction of a retort in order to do every sort of distillation on a large scale, ... ). A handwritten note on the title page of a copy that was in the collection of the state library of Cassel, Germany, states: ''"par Jean-Hyacinthe de Magellan"'' ( rittenby Joao Hyacinth de Magellan). Joao Magellan (1723–1790) was a Portuguese friar and scientist who settled in London. On p. 5 of the pamphlet, the ''Préface'' stated: ''"La première idée de la Machine distillatoire dont il sera question dans cet Ecrit, remote à l'année 1770. Il en fut d'abord exécuté différens modèles en petit, & notamment un dans le mois de Janvier 1773 ; enfin, peu de temps après, par les ordres de M. de Boynes, alors Ministre de la Marine, la Machine fut exécutée à Paris en grand, ... "'' (The first idea of a distillation device that is the subject of this work, arose in the year 1770. Different models were executed at first on a small scale, and in particular one in the month of January 1773 ; at last, shortly afterwards, at the order of Mr. de Boynes, then Minister of the Navy, the device was executed in Paris on a large scale, ... ) Illustrations in the pamphlet show a retort to which a tube was fitted. The tube carried the retort's vapors through a rectangular box, which acted as a condenser and in which cold water flowed from the condenser's lower end to its upper end—a counter-current condenser. In 1794, the German

pharmacist A pharmacist, also known as a chemist in English in the Commonwealth of Nations, Commonwealth English, is a healthcare professional who is knowledgeable about preparation, mechanism of action, clinical usage and legislation of medications in ...

Johann Friedrich August Göttling Johann Friedrich August Göttling (5 June 1753 – 1 September 1809) was a notable German chemist. Gottling developed and sold chemical assay kits and studied processes for extracting sugar from beetsFinnish pharmacist Jakob Gadolin (1719–1802) proposed condensers for use in distilleries and in laboratories, consisted of a metal jacket which surrounded the discharge tube from a distillation vessel and through which a countercurrent of cold water flowed. Also independently of Weigel, Pierre-Isaac Poissonnier (1720–1798), a physician to the king

Louis XV of France Louis XV (15 February 1710 – 10 May 1774), known as Louis the Beloved (), was King of France from 1 September 1715 until his death in 1774. He succeeded his great-grandfather Louis XIV at the age of five. Until he reached maturity (then defi ...

, published in 1779 a design of a still for producing freshwater from seawater aboard a ship. The apparatus consisted of a retort for boiling the seawater, a tube extending from the retort through a rectangular box filled with flowing cold water, fed by a separate tank. Liebig himself incorrectly attributed the design to Göttling. Liebig replaced the outer metal wall of Weigel's condenser by a glass tube, and used rubber hoses, instead of metal tubes, to convey water to and from the condenser.Liebig, Justus von; Poggendorff, J.C.; Wöhler, Fr., ed.s, ''Handwörterbuch der reinen und angewandten Chemie'' ictionary of pure and applied chemistry vol. 2 (Braunschweig, (Germany): Friedrich Vieweg und Sohn, 1842), article: "Destillation," pp. 526–554. O
p. 532, Fig. 29
a condenser is shown in which the inner glass tube containing the hot vapors from the distilling flask is now in direct contact with the cooling water in the condenser's jacket
Fig. 30 on p. 533
shows a condenser with a glass (not metal) jacket, for distilling small batches of material.

Design

The modern design consists of two concentric straight glass tubes, the inner one being longer and protruding at both extremities. The ends of the outer tube are sealed (usually by a blown glass ring seal), forming a water jacket, and is fitted with side ports near the ends for cooling fluid inflow and outflow. The ends of the inner tube, that carries the vapor and condensed liquid, are open; they are often fitted with

ground glass joint Ground glass joints are used in laboratories to quickly and easily fit leak-tight apparatus together from interchangeable commonly available parts. For example, a round bottom flask, Liebig condenser, and oil bubbler with ground glass joints may ...

s for secure and airtight connection to other equipment.

Efficiency

Compared to the simple air-cooled tube condenser of a

retort In a chemistry laboratory, a retort is a device used for distillation or dry distillation of substances. It consists of a sphere, spherical vessel with a long downward-pointing neck. The liquid to be distilled is placed in the vessel and heat ...

or the head of an

alembic An alembic (from , originating from , 'cup, beaker') is an alchemical still consisting of two vessels connected by a tube, used for distillation of liquids. Description The complete distilling apparatus consists of three parts: * the "" ...

, the Liebig condenser is more efficient at removing the heat of condensation and at maintaining a stable low temperature on the condensation surface.

References

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