During vacuum distillation, the pressure in the distillation equipment is reduced. Because of this reduced pressure, the boiling temperature of the mixture, which is supposed to be separated, is lowered. The positive effect is that other components, which are not sufficiently temperature-stable, can be distilled as well. In the application of distillation technology, the vacuum distillation is almost only used in laboratory practice.
Molecular distillation is a distillation which is accomplished in the medium vacuum range (1 – 0,001 mbar). In this method of distillation, the distance between pattern and condenser is very small, which leads to a short distillation phase. This procedure is one of the most gentle, thermal separating processes, by what it is very useful for thermal sensitive products. The low pressures and the little distances demand a great deal of the distillation technology.
During overpressure distillation, the pressure inside the equipment is increased and due to the increased pressure, the boiling points of the individual substances are moved apart. This procedure is used to separate substances with a very low boiling point, e.g. liquid gas.
During towing distillation (steam-towing distillation), water is vaporized and the fugitive, water-insoluble substance is towed.
The main field of application for this distillation technology is the winning of ethereal oil.