Question

"What other compounds are extracted along with caffeine into the tea? Use what you know about the relative polarity of the functional groups within these compounds to determine the final destination of the compounds (the tea bag, aqueous layer, or organic layer? Make a flow chart and include any reactions as necessary." organic solvent used was DCM (dichloromethane). In my notes I wrote that caffeine will precipitate and chlorophyll will stay in ethanol, but not brief enough to really understand. physical properties of reactants and products used was K2CO3, DCM, caffeine, and ethanol. The tea used was the English breakfast Tea. Please amswer all parts to this question

Answer 1

Extraction is a process which selectively dissolves one or more of the mixture compounds into a suitable solvent. The solution of these dissolved compounds is referred to as the Extract.The organic solvent dichloromethane is used to extract caffeine from an aqueous extract of tea leaves because caffeine is more soluble in dichloromethane (140 mg/ml) than it is in water (22 mg/ml) or alchohol. The tannins that are slightly soluble in dichloromethane can be eliminated by converting it to their salts (phenolic anions by adding sodium carbonate) (tannins are phenolic compounds of high molecular weight and being acidic in nature can be converted to salts by deprotonation of the -OH group) which remain in the water.

Tea powder is extracted from tea leaves which contain tannins, which are acidic in nature, a number of colored compounds and a small amount of unrecompensed chlorophyll and an important stimulant called Caffeine. Because of the presence of Caffeine, tea and coffee are gaining popularity as an addictive stimulant. An average 30g of tea can contain 20-ll0 mg of caffeine thereby making tea a significant source of caffeine compared to other beverages. Caffeine can stimulate nervous system and can cause relaxation of respiratory and cardiac muscles. Caffeine is well known to increase both the alertness level and attention span. But like all other addictives, tea also shows withdrawal symptoms like headache, nervousness and insomnia for a regular consuming person.


Caffeine, 1,3,7 - trimethylxanthine, belongs to a wide class of compounds known as alkaloids. These are plant derived compounds with complex structure containing nitrogen, and usually have roles in physiological activity. The melting point of Caffeine is 238°C.