What Is a Soxhlet Extractor?
Soxhlet extractor, also known as fat extractor or fat extractor. The Soxhlet extractor is composed of an extraction bottle, an extraction tube, and a condenser. There are siphon tubes and connecting tubes on both sides of the extraction tube, and the connection of each part must be tight to prevent air leakage. During extraction, wrap the sample to be tested in a degreasing filter paper bag and place it in an extraction tube. Petroleum ether is added to the extraction bottle, the extraction bottle is heated, the petroleum ether is vaporized, rises from the connecting pipe into the condenser, and condenses into a liquid and drips into the extraction pipe to extract the lipids in the sample. When the level of petroleum ether in the extraction tube reaches a certain level, the petroleum ether in which crude fat is dissolved flows into the extraction bottle through a siphon. The petroleum ether flowing into the extraction bottle continues to be heated, gasified, raised, and condensed, and then dripped into the extraction tube, and so on until the extraction is complete.
- One method for extracting compounds from a solid substance is to immerse the solid with a solvent for a long time and leaching out the required substance, that is, a long-term leaching method . This method takes a long time, uses a large amount of solvent, and is not efficient.
- More adopted in the laboratory
- Grind the solid material before extraction to increase the solid-liquid contact area. Then, the solid matter was placed in a filter paper bag and placed in an extractor. The lower end of the extractor was connected to a round bottom flask containing the leaching solvent, and the reflux condenser was connected to the upper end. The round-bottomed flask is heated to boil the solvent, and the vapor rises through the connecting tube and enters the
- Soxhlet extractor application example: extraction of crude caffeine. Specific steps are as follows:
- Use a filter paper to make a cylindrical filter paper cylinder. Weigh 10 g of tea leaves, mash the tea leaves with a mortar, put them in the filter paper cylinder, fold and seal the open end, put it in the extraction cylinder, install a 150 mL round bottom flask on an electric heating sleeve, place Add 2 zeolites, install the Soxhlet extraction device, and add two siphons of 95% ethanol from the reflux condenser on the upper part of the instrument. All the siphons are siphoned into the flask below to complete a siphon). Turn on the power and heat to reflux for 2 hours.
- During the experiment, it can be observed that with the progress of reflux, when the liquid level of the ethanol solution under reflux in the extraction cylinder is slightly higher than the top of the siphon tube of the Soxhlet extractor, the ethanol solution in the extraction cylinder siphons and flows back to the flask. Then reflux again, siphon, and record the number of siphons. After 5-6 siphons, when the color of the extract in the extraction tube becomes very light, it means that the extract has been mostly extracted, stop heating, remove the heating jacket, and cool the extraction liquid. Remove the Soxhlet extractor (if there is still a small amount of extraction liquid in the extraction tube, tilt it to flow into the round-bottomed flask), install a condenser to perform distillation, and pour it into an evaporation dish containing quicklime while the remaining 10 mL is still hot After being pasty, it will be dried and powdered (note that it should not be burnt). Then cover the evaporating dish with a filter paper pierced with many small holes (the piercing holes are upward), cover the filter paper with a glass funnel, and continue heating to make the caffeine sublimate. [1]