1. The ordinary distillation is separated at the boiling temperature, and the molecular distillation can be carried out at any temperature. As long as there is a temperature difference between the hot and cold sides, the separation can be achieved.
2. Ordinary distillation is a reversible process of evaporation and condensation. A phase equilibrium state can be formed between the liquid phase and the gas phase. In the molecular distillation process, molecules escaping from the evaporation surface directly fly to the condensation surface without colliding with other molecules in the middle. In theory, there is no possibility of returning to the evaporation surface, so the molecular distillation process is irreversible.
3. The ordinary distillation has bubbling and boiling phenomenon; the molecular distillation process is free evaporation on the surface of the liquid layer without bubbling.
4. The separation factor indicating the ordinary distillation separation ability is related to the vapor pressure ratio of the component, and the separation factor indicating the molecular distillation separation ability is related to the vapor pressure and molecular weight ratio of the component, and can be obtained from the relative evaporation speed.