Would it be a hard science fair project to extract caffiene from tea?

Question

if so do you have any ideas.

please nothing toooo elementry;)

Answer 1

No.  It's actually fairly elementary.

What level are you working at?

Answer 2

Place approximately 40 mL of water in a 100-mL beaker. Heat the water on a hot plate until it is almost boiling. Place a family sized tea bag (tea mass=7.5 g) into your hot water so that it is covered as much as possible with hot water. Cover the beaker with a watch glass and continue to heat for about 15 minutes. If the tea bag rises, push it back down using a test tube so that the tea is in constant contact with the hot water. If water evaporates during this step, you should add additional water.

Transfer the concentrated tea solution to two matching centrifuge tubes or test tubes, keeping approximately equal volumes in each tube. Be careful not to break the tea bag, as the presence of tea leaves in your solution will lead to additional difficulties in your separation. Add 0.5 g of sodium carbonate to the hot liquid in each tube. Cap the tubes and shake them until the solid dissolves.

Cool the tea solution to room temperature, using an ice bath if desired. (Remember that CH2Cl2 boils around 40 oC.) Add approximately 3 mL of dichloromethane to each tube. Cap the tubes and shake them gently for several seconds. Vent the tubes to release pressure built up by the volatile solvent, being careful to always point the tube away from your own face or a neighbor's face. Centrifuge the mixture to break the emulsion that forms. (Remember to balance the centrifuge by placing your matching tubes directrly across from each other.)

Remove the lower organic layer with a Pasteur pipet and transfer it to a test tube. Try not to transfer any of the dark aqueous solution along with the organic solvent. Add a fresh 3 mL portion of dichloromethane to the aqueous layers and repeat the extraction. If necessary, leave some of the organic layer behind to avoid transferring any of the aqueous mixture to your new container. Dry your organic layer by adding a small amount of anhydrous sodium sulfate.

Transfer the dry organic layer to a clean pre-weighed filter flask. Evaporate the dichloromethane by heating the flask in a hot water bath. When the solvent has evaporated, the solid caffeine will coat the bottom of the flask. Weigh the flask to get the mass of your crude caffeine.

Assemble a sublimation apparatus with a special test tube fitted with rubber tubing at the top. The rubber tubing allows the test tube to make a good seal in the mouth of the filter flask. Place ice in the test tube. Connect the filter flask to the vacuum. Once the apparatus is connected to the vacuum, ensure that all of the joints are tightly sealed. If the joints are not sealed tightly, the caffeine may escape from the apparatus. Make sure that your replenish the ice water bath with additional ice if necessary. A warm cold-finger will allow your caffeine to vanish into the house vacuum, never to be seen again. Heat your sample gently and carefully with a Bunsen burner to sublime the caffeine. Do not allow the rubber tubing to catch on fire. If it appears that your solid is disappearing from the bottom of the flask but not reappearing on the cold finger, STOP heating!! You probably have a leak or an inadequately cooled cold finger. When your sublimation is complete, discontinue heating. Allow the apparatus to cool while the vacuum is still on.

After the apparatus has cooled, remove the vacuum and carefully remove the inner tube so that you don't dislodge the purified caffeine from the cold finger. Obtain a melting point and mass of the purified caffeine. Lastly, calculate the percentage of caffeine in your tea sample.

Answer 3

The best way would be solvent extraction which I can't recommend.  Caffiene can also be extracted with very cold carbonated water but it won't be very pure.  You might want to think of something a little less messy.