Introduction of Soxhlet Extractor
What is a Soxhlet extractor? Click here to know more. What is the working Principle Of the Soxhlet Extractor? The upper part of the Soxhlet extractor is a condenser, the middle part is an extraction cylinder and the lower end is connected to a flask. When extracting materials, place the material powder in the extraction barrel and the solvent in the flask. After heating, the solvent in the flask will be heated and evaporated, and then enter the condenser through the side tube of the extraction barrel. The condensed solvent will drop onto the material in the extraction barrel. When the collected solution exceeds the top of the side siphon, it will flow back to the flask through the siphon. Then the above process can be repeated to achieve solvent recycling extraction until the effective ingredients are completely extracted. It has a wide range of applications in pharmaceutical, biological, food, environmental analysis, and other fields.
Advantages of Soxhlet Extractor
This is the most prominent advantage of the Soxhlet extractor. In this device, each time the material is contacted, the new solvent is condensed and returned, which keeps the concentration difference between the inside and outside of the material, and realizes the dynamic extraction. Compared with the general static extraction device, its extraction efficiency is significantly improved.
The reflux process can be carried out automatically with the help of a siphon. When the extraction liquid gathered in the extraction drum exceeds the top of the siphon, it flows back to the flask through the siphon. The whole device does not need any other power except for heating the evaporation flask, which avoids the tedious operation of changing the solvent many times during the extraction process.
Significantly reducing solvent consumption
As the solvent in the flask is heated and evaporated. Then enters the condenser. The condensed solvent extracts the material and then returns to the evaporation flask, so as to realize the solvent recycling, without adding new solvent, thus significantly reducing the amount of solvent.
Disadvantages of Soxhlet Extractor
Low extraction temperature
Because the device adopts the solvent obtained from the heated evaporation of the extraction solution performing recycling extraction, it is usually used to extract the components with good thermal stability. For such components, dynamic extraction with heating extraction is the ideal choice, which can obtain higher extraction efficiency. Soxhlet extractor circulates the solvent obtained from the condensate, which is difficult to carry out hot solvent extraction.
Long cycle time relying on the siphon
After the completion of the first siphon, the solution in the extraction cylinder will be emptied, and it will take a certain time for the condensate to drip down slowly, the extract to be re-impregnated. During extraction, the cooled solution often flows back to the flask in large quantities at one time, resulting in intermittent boiling.
A high boiling point solvent is not suitable
It is not suitable to use substances that are easily decomposed or discolored when heated, and solvents with high boiling points are also not suitable. When high boiling point solvent is used, its reflux speed is relatively slow and the extraction time is long, which affects the efficiency.
Inconvenient solvent recovery
After the leaching, the excess solvent in the extraction drum can be removed only after the device is removed, resulting in the impact of the solvent on the environment and the health of the laboratory personnel. Moreover, it is easy to leave a large amount of solvent in the residue, which makes it difficult for further treatment.