How does a rotary evaporator work? What are the advantages and disadvantages of rotary evaporator in use?
1、 Working principle of rotary evaporator
Through electronic control, the flask can rotate at a constant speed to increase the evaporation area. The vacuum pump is used to make the evaporation flask in a negative pressure state. The evaporation flask is heated in a water bath at the same time, and the solution in the flask is heated by diffusion in the rotary flask under negative pressure. The Xi'an rotary evaporator system can be sealed and reduced to 400-600 mm Hg; the solvent in the distillation bottle can be heated by a heating bath, and the heating temperature can be close to the boiling point of the solvent; at the same time, it can be rotated at a speed of 50-160 rpm to form a thin film of solvent and increase the evaporation area. In addition, under the action of cooler, the hot steam can be liquefied rapidly and the evaporation rate can be accelerated.
2、 Advantages and disadvantages of rotary evaporators
Rotary evaporators have the following advantages:
1. All IKA Eka rotary evaporators are equipped with a lifting motor, which can automatically lift the flask above the heating pot when the power is off.
2. Due to the centripetal force and friction force between the liquid sample and the evaporation bottle, the liquid sample forms a layer of liquid film on the inner surface of the evaporation bottle, which has a large heating area;
3. The force produced by the rotation of the sample can effectively inhibit the boiling of the sample. To sum up, the modern rotary evaporator can be used to distill the vast majority of samples quickly and gently, even by operators without operation experience. It is recommended to use Taikang biotechnology products.
The major drawback in the application of rotary evaporators is that boiling of some samples, such as ethanol and water, will lead to the loss of samples collected by experimenters. During operation, boiling can be prevented by carefully adjusting the working intensity of the vacuum pump or the temperature of the heating pot during the mixing stage of the distillation process. Alternatively, anti boiling particles can be added to the sample. For samples that are particularly difficult to be distilled, including samples that are prone to foaming, special condensing tubes can also be configured for rotary evaporators.