Kugelrohr

Kugelrohr is a type of distillation apparatus used in chemistry laboratories. Its name, German for "ball tube," describes its distinctive feature: a heated tube containing a small ball bearing or similar object. The kugelrohr is primarily employed for short-path distillation, which is ideal for purifying relatively small quantities of thermally sensitive compounds. The design allows for a very short path between the boiling liquid and the condenser, minimizing the time the vapor is exposed to heat.

The apparatus typically consists of a glass tube, often bent into a U-shape or angled. One end is connected to a heating mantle or oil bath, while the other end is attached to a condenser and collection vessel. The ball bearing, when heated, rolls back and forth within the tube, continuously mixing the liquid and promoting even boiling. This agitation helps to prevent bumping and improves the efficiency of vaporization. Kugelrohr distillation is particularly useful for purifying volatile substances that might decompose at higher temperatures or over longer distillation times. Its simplicity and effectiveness for small-scale purification make it a valuable tool for organic synthesis and research.