Soxhlet Extractor Application Example: Extraction of Crude Caffeine
A cylindrical filter paper tube was made from filter paper, 10 g of tea leaves were weighed, and the tea leaves were weighed into a filter paper tube, and the open end was folded and sealed, and placed in an extraction cylinder. A 150 mL round bottom flask was mounted on the electric heating sleeve. 2 zeolites were placed, 100 mL of 95% ethanol was weighed, poured into the flask from the extraction cylinder, the Soxhlet extraction device was installed, the power was turned on, and the mixture was heated to reflux for 2 hours.
During the experiment, it can be observed that as the reflux progresses, when the liquid level of the ethanol solution under reflux in the extraction cylinder is slightly higher than the tip of the Soxhlet extractor, the ethanol solution in the extraction cylinder is siphoned and flows back into the flask. Then reflow, siphon, record the number of siphons. After siphoning 5-6 times, when the color of the extract in the extraction cylinder becomes very shallow, it means that most of the extract has been extracted, stop heating, remove the electric heating sleeve, and cool the extract. Remove the Soxhlet extractor (if there is still a small amount of extract in the extraction cylinder, tilt it all to the round bottom flask), install a condensing tube for distillation, and pour it into the evaporating dish containing the quicklime when it is about 5 mL left. Stir into a paste and evaporate to a powder. Then use sublimation to obtain its crystal