Extraction of Caffeine From Tea Leaves

Plants that contain caffeine include: tea, coffee, cocoa among others. The chemical caffeine can be extracted from these plants using a chemical procedure. For instance, when extracting caffeine from tea leaves, one can use dichloromethane and sodium hydroxide, diethyl ether, propanol, celite and hexane.

Procedure: Weigh a specific amount of tea leaves preferably 5g place in an Erlenmeyer flask. Add 20 ml of dichloromethane mixed with 0.2M of sodium hydroxide. Seal the flask and swirl to allow the tea leaves to mix with the solvent. Caffeine dissolves in the solvent and other compounds of tea are left insoluble. After that use a Buchner funnel for filtration. Before using the celite paper, dampen it in dichloromethane. Vacuum filtration is more perfect than a normal filter funnel. The liquid collected contains caffeine it. Next is to evaporate the liquid through heating. The remaining solid is caffeine and other compounds.

To obtain pure caffeine from the above procedure, one needs to use solubility of caffeine against other compound. Allow the beaker to cool and wash the caffeine with diethyl ether and hexane. Using a pipette, one removes the other liquid and remains with solid caffeine. What follows is to dissolve this again dichloromethane. Filtration is then done to remove other undissolved compounds to remain with soluble caffeine. Place the liquid into a test tube then heat it at a 560 C in a water bath. Add 2ml of propanol dropwise until the solid dissolve. Remove it from the water bat and allow it to cool. To solidify pure caffeine, one needs to add 1ml of hexane and a solid caffeine will form. Dry the solid and weigh it. To check for purity, it is good to check for melting point which falls around 2340 C (Helmenstine, 2019).

Conclusively, the above chemicals should be handled with care. It is good to check for the safety operation procedures of the above chemicals to avoid accidents in the lab.

References

Helmenstine, Anne Marie, Ph.D. (2019, July 3). How to Extract Caffeine from Tea. Retrieved from https://www.thoughtco.com/how-to-extract-caffeine-from-tea-608211″,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
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