Rotary evaporators are widely used in small and medium-sized experiments. They are necessary instruments for laboratory experiments such as distillation, concentration, crystallization, purification and separation.
The experimental sample is distilled under reduced pressure in a spherical flask, and the sample is rotated at a constant speed to form a film under the action of centrifugal force, so as to increase the evaporation area and improve the evaporation efficiency. The sample recovery rate of rotary evaporators is not only related to the properties of materials, but also greatly affected by the way we use rotary evaporators. Next, let's talk about the impact of vacuum on sample recovery.
1. Too fast rotation speed of the rotary vaporizer will affect the recovery rate. When the vacuum is too high, the experimental target will evaporate and lose along with the solvent. In addition, it should be noted that the solvent should not bubble during spinning. We can control it by reducing the temperature and rotating speed.
2. When the vacuum is too high, we can add a buffer bottle between the vacuum pump and the rotary evaporator, which can effectively prevent the experimental substance from being sucked into the vacuum pump. If a diaphragm pump is used, there will be a knob near the meter to roughly adjust the pressure in the system.
3. The temperature of the condenser is the key factor affecting the recovery rate. If the temperature of the condenser is too low, the evaporated experimental substances will accumulate in the condenser and cannot be dissipated in time. When the vacuum pump is working, the experimental substances will be sucked into the vacuum pump. In addition, we need to pay attention to that if our subjects are substances such as ether, we need to change the water in the pump frequently, otherwise it is easy to cause a fire.
