Isolation Of Caffeine From Tea (Chemistry)

Isolation of Caffeine from Tea
CHEM243A
2-23-11

Abstract:
The intend of this experiment was to isolate caffein from a tea bag. Once isolated, the caffeine was purified exploitation sublimation. The percent recovery was calculated to be 83.3%. The melting orientate of the original substance was 51ºC-139ºC. Since it was inaccurate, the melting promontory of some other groups sample was recorded. It was determined to be 219ºC-227ºC.

Results:
part recovery=100*(weight of pure/weight of impure)
Weight of gravelly Caffeine| Weight of Purified Caffeine| Percent Recovery|
0.018 g| 0.015 g| 83.33%|

| Started Melting| Completely Melted|
Our Sample| 51| 139|
Other Groups Sample| 219| 227|

Since the melting buck determined was so different from the known melting point of caffeine, there essential have been impurities in the sample. This is also wherefore some of sample melted immediately while the stick took much longer. This wide melting range also indicated impurities.
reciprocation:
The procedure used to isolate the caffeine from a tea bag is very particular. The first blackguard is to submerge the tea bag in hot water, much like when do tea to drink. This separates the soluble fraction from the insoluble cellulose, non-hydrolyzable, and tannins.



This step is moderately different from brewing tea because only 10 mL of water is used. All of the water immediately absorbs into the bag and must be squeezed out. Brewing tea to drink requires much more water. The next step in isolation is to add dichloromethane. The purpose of this step is to separate the aqueous layer from the organic layer. This absorbs unloosen of the K-salts of gallic acid and glucose. The organic layer still contained caffeine and chlorophyll and any other organic compounds. The final step is to purify the caffeine from any impurities. Sublimation is the technique used. First, the vacuum is applied. whence ice water is placed in the inner tube. Last, the come alive is turned on below the device. The mixture of...If you want to get a full essay, order it on our website: Ordercustompaper.com



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