Extraction and Separation of Caffeine from Tea

Materials Required

Setup: Place a 250ml beaker on a hotplate, fill with about 150ml of distilled water.
Add Tea Bags: Open and place several tea bags into the beaker.
Prevent Evaporation: Cover with a watch glass.
Heat: Bring to a boil, then remove from heat and let cool.

Prepare Funnel: Add 20ml of brewed tea to the separatory funnel. Ensure the stopcock is closed.
- Check Stopcock: Closed if hole is 90 degrees off from vertical.
Add Solvent: Pour 20ml of dichloromethane (DCM) into the funnel.
- Observation: DCM will sink to the bottom.
Mix: Cap the funnel and gently shake.
- Vent: Turn over and open valve to release pressure.
- Repeat Shaking: Several times for higher yield.
Separate Layers: Wait for organic and aqueous layers to separate.
- Speed up Separation: Use a glass rod to pop bubbles.
Collect Organic Layer: Drain bottom (organic) layer into collection vessel.
Repeat Extraction: Perform 1-2 more extractions with DCM, collecting in the same vessel.

Remove Aqueous Layer: Use anhydrous sodium sulfate to dry.
- Swirl Flask: Traps remaining tea, moves it to the bottom.
- Add More if Needed: Until all water is contained.
Transfer and Filter: Use standard gravity filtration to move dried material to another flask.
- Filter Setup: Fold filter paper, use a glass rod to assist flow.

Evaporate DCM: Heat gently in a hood using a hotplate.
- Low Boiling Point: DCM evaporates quickly.
Result: Remaining crude caffeine forms a solid.
- Further Purification: Possible from this crude solid.

Solubility: Caffeine is slightly soluble in water; more in organic solvents like DCM.
Safety Note: DCM should be handled in a fume hood due to low boiling point and volatility.