The Extraction of Caffeine from Tea Many undergraduate laboratory manuals describe lengthy procedures for extracting caffeine from tea. Several notes1 in this Journal have indicated improvements or alternative sources, such as coffee, cola syrup, No-Dm tablets etc. When given the chmce however, we have found that the majority of our students chose tea. The procedure (described helow) dispenses with all filtrations, since the tea is conflned to tea bags and tannins are held in solution by the sodium carbonate. The product ohtained was less colored than comparahle samples obtained using either calcium carbonate or lead acetate to precipitate the tannins, and had sharper mp. The whole experiment, including reerystallization, can readily he accomphshed in an afternoon laboratory period. Fifty grams of tea hags, 200 ml of water, and 35 g of sodium carbonate are heated just to boiling for 20 min. After cooling, the solution is extracted with 5 X 30 ml portions of diehloromethane, using a gentle swirling to prevent emulsion formation. The extract is evaporated to dryness on a waterbath and the solid residue recrystallized by dissolving in 5 ml of hot benzene and adding 60-80'C petroleum ether dropwise till cloudiness develops. Student yield = 0.1-0.2 g colorless crystals, mp 225-228°C. 'See for example Auk, A., and Craig, R., J. Chem. Edue., 46, 767 (1969); MayC, A. L., J. Chem. Edue. 49, 194 (1972);5. A. Laswick and Laswick, P. H., J. Chem Educ., 49,708 (1972).
University of Victoria Victoria. B. C. Canada
R. H. Mitchell W. A. Scott P. R. West
Volume 51. Number 1, January 1974
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