Liebig

Named after Justus von Liebig who popularised its use, the Liebig condenser is probably the most widely used condenser. The condenser consists of a water jacket surrounding the vapour tube resulting in vapours condensing on the inner glass wall and the droplets run down the wall due to the effects of gravity. These condensers are widely used in a reflux set up where the ground glass cone fits into the socket of a round bottom flask. Modern Liebig condensers have screw-thread fittings which are removed to fit water tubing, rather than pushing the tubing directly onto the condenser. Some Liebig condensers do not have screw-threads and the tubing is carefully slid onto the water inlets. The flow of water in a Libig condenser should be from the bottom to the top in order to ensure the water jacket is filled.

Allihn

Designed by the German chemist Felix Richard Allihn, the Allihn condenser is a modification of a Liebig condenser, where the inside walls of the condenser has bulbs along its length to increase its surface area. There are various specific designs of Allihn condensers depending on the exact nature of the bulbs inside the condenser. This principle has also been applied to other condensers, for example in the hybrid Hartzler condenser. These condensers are not suitable for distillations as distillates get stuck in the bulbs in the condenser rather than flowing into the collection flask.

Davies

The Davies condenser is a modification of the Liebig condenser and has an additional water cooling section inside the condenser vapour tube as well as the water jacket. These are often used in refluxes or distillations where very low boiling solvents are used in order to minimise the loss of the solvent.

There are a number of designs of coil condensers which are used and each design has its own advantages, disadvantages and intended uses. In general coil condensers offer a much greater surface area than jacketed condensers and as a result are predominantly used where very effective cooling is required.

Conventional Coil

A conventional coil condensor has the cooling water run through the coil in the condenser and the vapours are contained within the condenser wall and condense onto the coil. This offers a much greater surface area compared to a Liebig condenser and is used where large amounts of vapour require cooling, for example in continuous extraction (eg Soxhlet). However, the outer wall of the condenser can warm up with prolonged use, and for some experiments a hybrid condenser may be more appropriate.

Dimroth

Named after the German chemist Otto Dimroth, the condenser is a modification of a conventional coil condenser where both the water inlet and outlet are towards the top of the condenser.  Water travels in a tube down the middle of the condenser to the bottom, and then a coil ascends around the water tube until it reaches the top of the condenser. The vapous travel around the water coil and the increased surface area being cooled makes the condenser more efficient than the conventional coil condenser. Dimroth condensers are used with the rotary evaporators found in teaching labs.

Graham

Graham condensers have a water jacket in a similar fashion to a Liebig condenser, but the vapour passes through a coil, with the much greater length giving a larger surface area to cool the vapours. The Graham condensers are much easier for a glassblower to produce than a conventional coil condenser, but are rarely used nowadays as conventional coil condensers are mass-manufactured making them readily accessible to buy. These condensers are not suitable for distillations as distillates get stuck in the coils in the condenser.

Triple-jacket Coil

A triple jacket coil condenser is a combination of a Davies and a conventional coil or Dimroth condenser. These offer a huge surface area for cooling vapours, but are complex to build and therefore rather expensive. The coolant runs through the coil, then through the jacket before exiting the condenser.

Friedrichs

There are many varients of the Friedrichs condenser, but all share the same basic design of a large inner spiral tube offering a very large surface area for cooling. They asre most commonly found on rotary evaporators as they offer highly efficient cooling. Whilst they are available for other uses, the level of cooling they provide is rarely necessary.

Hartzler

Simple

Simple glass tube condensers have been around for a long time and are ideal for solvents with realtively high boiling points where the heat is easily dissapated to the surroundings. They have a relatively small surface area, and have only limited cooling abilities. However, this is usually sufficient for solvents such as toluene and the condensers are the cheapest form of cooling available.

Vigreux

Predominantly used to increase the pathlength in distillations which allows separation of closely boiling components, Vigrux columns can also be used as a condenser. The condenser has indentations from the outer wall into the vapour tube which results in a larger surface area than a simple air condenser so they are able to cool more efficiently. However they are still usually only suited for condensing compounds with relatively high boiling points.

Snyder

A Snyder condenser is similar to a Vigreux condenser, but has glass 'teardrops' along the length of the column to increase the surface area beyond that of a Vigreux column.

Widmer

Developed by Gustav Widmer, the condensing column consists of a spiral ascending a rod in the centre of the condenser. The vapours travel several times the length of the condenser before reaching the exit at the top. As a result, the condenser has a very large surface area.

Condensyn

The condensyn is a ribbed condensor with a larger surface area than a simple air condenser, in a simlar way to an Allihn condenser.

Findenser

Cold Finger

Cold fingers are predominantly used for sublimation and consist of a glass tube which has water flowing through it and usually a glass cone to fit into other ground-glass joints. For sublimation, a solid is placed in a vessel into which the cold finger is placed and the vessel slowly warmed causing the solid to sublime. The gas then condenses onto the cold finger in pure form.

Dewar