分馏,精馏

As the solution to be purified is heated, its vapors rise to the fractionating column. 当要被提纯的液体受热时，它的蒸汽上升到分馏柱。

Reaction is carried out under a fractionating column that allows aldehyde to pass but returns alcohol to the reaction vessel. 反应是在装有分馏柱的反应器中进行的，分馏柱能让醛通过但使醇回流到反应器中。