Schlenk flask

They may be purchased off-the-shelf from laboratory suppliers or made from round-bottom flasks or glass tubing by a skilled glassblower.

The side arm contains a valve, usually a greased stopcock, used to control the flask's exposure to a manifold or the atmosphere.

While the flask is connected to the line under a positive pressure of inert gas, the septum can be replaced with other apparatus, for example a reflux condenser.

Schlenk bombs include structurally sound shapes such as round bottoms and heavy walled tubes.

In addition, all Schlenk bombs are designed to withstand the pressure differential created by the ante-chamber when pumping solvents into a glove box.

In some situations, however, Schlenk bombs are less convenient than standard Schlenk flasks: they lack an accessible ground glass joint to attach additional apparatus; the opening provided by plug valves can be difficult to access with a spatula, and it can be much simpler to work with a septum designed to fit a ground glass joint than with a Teflon plug.

The smaller neck includes the threading required for a teflon plug to be screwed in perpendicular to the flask.

Once connected, the plug valve can be partially opened to allow the solvent in the Straus flask to be vacuum transferred to other vessels.

Or, once connected to the line, the neck can be placed under a positive pressure of inert gas and the plug valve can be fully removed.

This allows direct access to the flask through a narrow glass tube now protected by a curtain of inert gas.

The most common configuration of a solvent pot is a simple round bottom flask attached to a 180° adapter fitted with some form of valve.

The pot can be attached to a manifold and the contents distilled or vacuum transferred to other flasks free of soluble drying agents, water, oxygen or nitrogen.

Three Schlenk flasks with 500, 250 and 100 mL volume on cork rings.
A pear-shaped Schlenk flask . The flask's sidearm contains a greased stopcock valve, and the flask is capped with a Suba•Seal septum that has not been turned down.
A heavy walled, tube shaped, Schlenk bomb fitted with a large bore plug valve designed for high temperature closed system reactions.
A Straus flask often called a solvent bomb . "Solvent bomb" is any Schlenk bomb dedicated to storing solvent. It is the construction of the flask neck which makes a Straus flask unique.
A solvent pot ready to have its dried and degassed contents vac transferred to another reaction vessel. This pot contains dibutyl ether dried over sodium and benzophenone , which gives it its purple color.