Molecular distillation - Bunshijouryu

This refers to distillation under a high vacuum (about 1.3 Pa). It is used to separate substances that have a high boiling point and are prone to thermal decomposition or polymerization, and has also been industrialized to separate various vitamins (vitamins A, E, K, etc.) and glycerides. At a certain vacuum and temperature, there is a cooling surface within the free path of the liquid molecules, and if no molecular collisions occur, the liquid will be recovered on the cooling surface, so it is circulated by having the liquid flow down the evaporation surface or flow in a centrifugal direction on the rotary evaporation surface. In general, the evaporation rate G of a molecule is expressed by the following formula, where A is the surface area, P is the vapor pressure, M is the molecular weight, and T is the absolute temperature.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

高真空下(1.3 Pa 程度)における蒸留をいう．高沸点で熱分解や重合しやすい物質の分離に用いられ，各種ビタミン(ビタミンA，E，Kなど)やグリセリドの分離に工業化もされている．ある真空度と温度下における液体分子の自由行程範囲内に冷却面があり，分子衝突が起こらなければ冷却面に回収されるので，液体が蒸発面上を流下する方式や回転蒸発面上を遠心方向に流れる形式で環流させている．一般に，分子の蒸発速度Gは，表面積A，蒸気圧P，分子量M，絶対温度Tとして，以下の式で表される．

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