Büchner flask

Büchner Flask

A Büchner flask, also known as a vacuum flask, filter flask, side-arm flask, or Kitasato flask, is a piece of laboratory equipment used in filtration. It is named after the German chemist Ernst Büchner.

Design and Function

The Büchner flask is typically made of glass and has a cylindrical shape. It features a side-arm tube, which allows it to be connected to a vacuum source. The main body of the flask is designed to hold a liquid or solid sample to be filtered, while the side-arm is used to create a vacuum that drives the filtration process.

The top of the Büchner flask is typically fitted with a Büchner funnel, which contains a ceramic or paper filter. The sample to be filtered is placed in the funnel, and the vacuum created by the flask pulls the liquid through the filter, leaving the solid particles behind.

Uses

Büchner flasks are commonly used in laboratories for filtration tasks, such as separating solids from liquids in a mixture. They are also used in the process of recrystallization, where a solution is cooled to form crystals, which are then separated from the remaining liquid using the Büchner flask.

In addition to filtration, Büchner flasks can be used in other laboratory procedures that require a vacuum, such as in the process of vacuum distillation.

Safety Considerations

When using a Büchner flask, it is important to ensure that the flask is not damaged or cracked, as this could cause the flask to implode when a vacuum is applied. It is also important to use the correct size of Büchner funnel and to ensure that the filter is properly seated to prevent leaks.

See Also

• Laboratory glassware
• Filtration
• Vacuum distillation
• Recrystallization (chemistry)