The working principle of rotary evaporator and the reasons affecting the recovery efficiency?

The rotary evaporator is now widely used in small and medium-sized experiments, and is a standing instrument for laboratory experiments such as distillation, concentration, crystallization, purification, and separation. The experimental sample is subjected to vacuum distillation in a spherical flask, and a thin film is formed under the action of centrifugal force by constant rotation, thereby increasing the evaporation area and improving the evaporation efficiency.

The sample recovery rate of a rotary evaporator is not only related to the properties of the material, but the way we use the rotary evaporator can also have a significant impact on the recovery rate. Next, let's talk about the reasons that affect solvent recovery.

1. The rotation speed of the rotary evaporator is too fast, which can affect the recovery rate. In the case of high vacuum, the experimental target will evaporate and lose along with the solvent. Also, please note that the solvent should not bubble during rotary evaporation. We can control it by reducing the temperature and rotation speed.

2. In the case of excessive vacuum, we can add a buffer bottle between the vacuum pump and the rotary evaporator to effectively prevent the experimental substance from being sucked into the vacuum pump.

3. The temperature of the condenser is the key factor affecting the recovery rate. If the temperature of the condenser is too low, it will cause the evaporated experimental substance to accumulate in the condenser and cannot dissipate heat in a timely manner. When the vacuum pump is working, the experimental substance will be sucked into the vacuum pump. Additionally, we need to be aware that if our experimental subject is a flammable solvent, we need to frequently change the water in the pump, otherwise it can easily cause a fire.