What is the Difference Between Reflux and Soxhlet Extraction

The key difference between reflux and soxhlet extraction is that reflux extraction involves only a flask and cooling above, whereas soxhlet extraction involves a specific apparatus called the soxhlet extractor.

Reflux is an analytical technique that involves the condensation of vapors and the return of the condensate to the system from which the condensate originated. Soxhlet extraction is an analytical extraction method using a specific extractor called the soxhlet extractor, which is useful for distillation purposes.

CONTENTS

1. Overview and Key Difference
2. What is Reflux Extraction
3. What is Soxhlet Extraction
4. Reflux vs Soxhlet Extraction in Tabular Form
5. Summary – Reflux vs Soxhlet Extraction 

What is Reflux Extraction?

Reflux extraction is an analytical technique that involves the condensation of vapors and the return of the condensate to the system from which the condensate was originated. This process is useful in industrial and laboratory applications where distillations are used. Moreover, this technique is useful in chemistry for supplying energy in order to keep reactions over a long time period.

In the industrial distillation processes, reflux is useful for large-scale distillation columns and for fractionators, including petroleum refineries, petrochemical plants, chemical plants, and natural gas processing plants.

In laboratory applications, we can place reactants and the solvent mixture in a round bottom flask. Then, we can connect it to a water-cooled condenser that typically opens to the atmosphere at the top. Thereafter, the round bottom flask is heated, allowing the boiling of the reaction mixture. The vapor that forms from the mixture undergoes condensation through the condenser, thereby returning to the round bottom flask under gravitation. This technique is important because it can thermally accelerate the reaction by conducting the process at an elevated and controlled temperature at the ambient pressure instead of losing a large amount of the mixture.

What is Soxhlet Extraction?

Soxhlet extraction is an analytical extraction method using a specific extractor called the soxhlet extractor that is useful in distillation purposes. The soxhlet extractor is a laboratory apparatus invented by Franz von Soxhlet in 1879. Originally, this apparatus was designed to extract lipid from a solid material. More importantly, this method is useful when there is a limited solubility of the desired compound in a solvent and when the impurity is not soluble in the solvent. Moreover, this technique can allow the unmonitored and unmanaged operation along with the recycling of a small amount of solvent in order to dissolve a large amount of the material.

There are three major parts of a soxhlet extractor: percolator, thimble, and siphon. The percolator is important as a boiler and reflux that can circulate the solvent. The thimble is typically made of thick filter paper and can retain the solid that we are going to extract. Finally, the siphon is the part that periodically empties the thimble.

What is the Difference Between Reflux and Soxhlet Extraction?

Reflux and soxhlet extraction are important industrial techniques that are useful in distillation applications. The key difference between reflux and soxhlet extraction is that reflux extraction involves only a flask and cooling above, whereas soxhlet extraction involves a specific apparatus called the soxhlet extractor.

The below infographic lists the differences between reflux and soxhlet extraction in tabular form for side by side comparison.

Summary – Reflux vs Soxhlet Extraction

Reflux is an analytical technique that involves the condensation of vapors and the return of the condensate to the system from which the condensate was originated. Soxhlet extraction is an analytical extraction method using a specific extractor called the soxhlet extractor that is useful in distillation purposes. The key difference between reflux and soxhlet extraction is that reflux involves only a flask and cooling above, whereas soxhlet extraction involves a specific apparatus called the soxhlet extractor.

Reference:

1. “Soxhlet Extraction.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Continuous Binary Fractional Distillation“ (CC BY-SA 3.0) via Commons Wikimedia
2. “Soxhlet mechanism” By Tomasz Dolinowski – Own work (CC0) via Commons Wikimedia