What is a rotary evaporator?

Fractional Distillation, also known as Fractionation, is the technique of separating volatile components with different boiling points in a mixture into different parts, which is used for the purification of chemicals or the separation of mixtures in order to obtain some certain components. Without new material produced in the process, Fractional Distillation merely separates mixtures which is regarded as a physical change.

Working Principle of Fractional Distillation

Fractional Distillation can complete multiple vaporization-condensation processes in one operation by utilizing fractional columns.

After boiling a mixture, the vapor enters the fractional column and is partially condensed. The condensate contacts the rising vapor during the descending process, and they exchange heat. The high boiling point components in the vapor are condensed while the low boiling point components still rise in vapor state. The low boiling point components in the condensate are vaporized under heating while the high boiling point components still drop in liquid form. Hence, the low boiling point components increase in the rising vapor, and the high boiling point increase in the falling condensate. It can be considered as continuous ordinary distillation after multiple such heat exchanges. As a result, the low boiling point components and high boiling point components are separated. The vapor of low boiling point components constantly increase and then is distilled out. The high boiling point components continuously flow back into the distillation flask.