Perkin triangle
Encyclopedia
A Perkin triangle is a specialized apparatus for the distillation
of air-sensitive materials. It is named after William Henry Perkin Jr.
, whose design was approximately triangular
in shape. The image opposite shows a more modern version in which the glass taps have been replaced with more air-tight Teflon taps.
Some compounds have high boiling points as well as being air-sensitive. A simple vacuum distillation
system can be used, whereby the vacuum is replaced with an inert gas after the distillation is complete. However, this is a less satisfactory system if one desires to collect fractions under a reduced pressure. To do this a "pig" adaptor can be added to the end of the condenser, or for better results or for very air-sensitive compounds a Perkin triangle apparatus can be used.
The Perkin triangle uses a series of glass or Teflon taps to allow fractions to be isolated from the rest of the still, without the main body of the distillation being removed from either the vacuum or heat source, so that the reflux may continue. To do this, the sample is first isolated from the vacuum by means of the taps; the vacuum over the sample is then replaced with an inert gas (such as nitrogen or argon) and can then be stoppered and removed. A fresh collection vessel can then be added to the system, evacuated and linked back into the distillation system via the taps to collect a second fraction, and so on, until all fractions have been collected.
for storage. Depending on the boiling point of the solvent a vacuum can be applied.
Distillation
Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
of air-sensitive materials. It is named after William Henry Perkin Jr.
William Henry Perkin, Jr.
William Henry Perkin, Jr. was an English organic chemist who was primarily known for his groundbreaking research work on the degradation of naturally occurring organic compounds.-Early life:...
, whose design was approximately triangular
Triangle
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
in shape. The image opposite shows a more modern version in which the glass taps have been replaced with more air-tight Teflon taps.
Some compounds have high boiling points as well as being air-sensitive. A simple vacuum distillation
Distillation
Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
system can be used, whereby the vacuum is replaced with an inert gas after the distillation is complete. However, this is a less satisfactory system if one desires to collect fractions under a reduced pressure. To do this a "pig" adaptor can be added to the end of the condenser, or for better results or for very air-sensitive compounds a Perkin triangle apparatus can be used.
The Perkin triangle uses a series of glass or Teflon taps to allow fractions to be isolated from the rest of the still, without the main body of the distillation being removed from either the vacuum or heat source, so that the reflux may continue. To do this, the sample is first isolated from the vacuum by means of the taps; the vacuum over the sample is then replaced with an inert gas (such as nitrogen or argon) and can then be stoppered and removed. A fresh collection vessel can then be added to the system, evacuated and linked back into the distillation system via the taps to collect a second fraction, and so on, until all fractions have been collected.
Solvent drying
A Perkin triangle is also a convenient device for drying solvents. The solvent can be allowed to reflux over a drying agent housed in the still pot (shown as 1 in the figure) for a suitable time to affect the drying of the solvent. The collecting tap (shown as 5 in the figure) can then be opened to collect the solvent in a Schlenk flaskSchlenk flask
A Schlenk flask, or Schlenk tube is a reaction vessel typically used in air sensitive chemistry, invented by Wilhelm Schlenk. It has a side arm fitted with a PTFE or ground glass stopcock which allows the vessel to be evacuated or filled with gases...
for storage. Depending on the boiling point of the solvent a vacuum can be applied.