Why does a rotary evaporator need a vacuum pump?

The vacuum pump of a rotary evaporator is one of the core components of the entire device. Its main function is to create a vacuum environment by reducing the air pressure in the system, thereby achieving the following functions:

1. Reduce the boiling point of the solvent to avoid high temperature damage

Principle: The boiling point of the liquid decreases as the air pressure decreases (for example, the boiling point of ethanol is 78°C at normal pressure, and the boiling point can be reduced to about 30°C when the vacuum degree reaches 0.09MPa).

Function:

For heat-sensitive substances (such as proteins and natural products), the solvent can be evaporated quickly at low temperatures to avoid high-temperature decomposition.

Save energy consumption, no need to heat to the normal pressure boiling point.

2. Speed up the evaporation rate

Principle: In a vacuum environment, solvent molecules are more likely to escape from the liquid surface, and the evaporation rate is significantly increased.

Function:

With a rotating evaporating bottle (increasing the surface area of the liquid), the sample can be quickly concentrated to improve the experimental efficiency.

3. Maintain the system vacuum to prevent contamination

Principle: The vacuum pump continuously pumps air to maintain a stable vacuum in the evaporating bottle.

Function:

Prevent air, moisture or impurities from entering the system to ensure sample purity.

For easily oxidizable substances, the vacuum environment can isolate oxygen and prevent oxidation and deterioration.

4. Adapt to the evaporation needs of different solvents

Vacuum pump type of Zhengzhou Elab:

Water circulation vacuum pump: The vacuum degree is relatively low (about - 0.09MPa), suitable for low boiling point solvents (such as ethanol, acetone).

Oil rotary vane vacuum pump: The vacuum degree is higher (up to - 0.1MPa), suitable for high boiling point solvents (such as DMF, DMSO).

Selection basis: Select a suitable vacuum pump according to the boiling point of the solvent and the experimental requirements.

Summary

The vacuum pump is the key to the vacuum distillation of the rotary evaporator. Its core value lies in the low temperature, high efficiency and safe treatment of solvents. It is widely used in sample concentration and purification in the fields of chemistry, biology, and pharmaceuticals.