Molecular distillation is a distillation method operated under high vacuum, in which the average free path of vapor molecules is greater than the distance between the evaporation surface and the condensation surface, allowing for the separation of liquid mixtures by utilizing the differences in evaporation rates of each component in the feed liquid. Molecular distillation is a special liquid-liquid separation technique that differs from traditional distillation in that it relies on the principle of boiling point difference for separation. Instead, it achieves separation by the difference in the average free path of molecular motion of different substances.