The short-path distillation (molecular distillation) is equipped with a inside condenser which is opposite to the heating surface, and make the operation pressure reduce to under 0.001mbar. Its relative low boiling temperature is very suitable to the material with heat sensitive and high boiling point.
What Is Short-Path Distillation?Short-path distillation is a distillation technique that involves the distillate travelling a short distance. This method is typically used to separate mixtures by virtue of differences in boiling point under reduced pressure. When the mixtures needed to be purified is heated, its vapor will rise to the vertical condenser and then be cooled by the cold water.This technique is often used for compounds which are unstable at high temperatures, cause a decrease of boiling temperature can be obtained by reducing the operating pressure.Short-path distillation, also named as molecular distillation, is conducted in vacuum. The mean free path of the vapor molecules is larger than the distance between the evaporating surface and the condensing surface. With this difference, the liquid or the liquid mixture can be separated. Under certain circumstance, the degree of freedom of the molecular is inversely proportion to pressure.The advantage is that the heating temperature can be considerably lower (at reduced pressure) than the boiling point of the liquid at standard pressure, and the distillate only has to travel a short distance before condensing. A short path ensures that little compound is lost on the sides of the apparatus.
The Working Principle Of The Short-Path Distillation Equipment:
- This apparatus is mainly employed to separate different liquid. It’s different from traditional distillation equipment because it separates the mixtures through the difference between the mean free path of the molecules and the distance between the evaporator and the condenser.
- Light and heavy molecular would leave the surface for liquid to gas phase when the liquid mixture is heated. However, the free paths of the light and heavy molecular are different and the free paths among different molecular are also different. If we set the position of the condenser reasonably, some light molecular would arrive the condenser and be condensed and discharged, while the heavy molecular can not. Thus the two liquid can be separated.
- It is the difference of pressure that drives the vapor flow, because even little pressure would push the vapor.
- Short-path distillation equipment can be used to separate substances that are not easily separated. Molecular distillation equipment lost little heat because its special structure make its inner pressure much lower than many normal distillation apparatuses.
- Short-path distillation equipment is especially suitable to separate substances that are of high boiling point, heat-sensitive and easily oxidated.
- Short-path distillation equipment has special structure, and the most important part of it is distillate film. Moreover, this equipment is so efficient that some light molecular would reach the condensing surface quickly.