Caffeine Extraction from Tea and Coffee Experiment PDF

## EXPERIMENT 5: SEPARATION AND PURIFICATION TECHNIQUES -3: ### CAFFEINE EXTRACTION FROM TEA AND COFFEE **Purpose of the experiment:** Removing caffeine from tea or coffee solution with the help of suitable solvent (decaffeination). **Introduction** First, a solvent that dissolves an organic or...

## EXPERIMENT 5: SEPARATION AND PURIFICATION TECHNIQUES -3: ### CAFFEINE EXTRACTION FROM TEA AND COFFEE **Purpose of the experiment:** Removing caffeine from tea or coffee solution with the help of suitable solvent (decaffeination). **Introduction** First, a solvent that dissolves an organic or inorganic substance in a homogeneous or heterogeneous mixture but does not dissolve the other substance in the mixture is chosen for the method of extraction. By moving it through the solvent, the mixture is mixed with this solvent to isolate the product to be extracted. It is divided into the extraction of solid-liquid and liquid-liquid. A suitable solvent from extraction: - To be well purified, it should dissolve the material - For easy removal, the boiling point should be strong - The substance to be purified or other solvent should not react - The temperature for flammability should not be low or harmful. As an extraction solvent, it is also used for ether, benzene, chloroform and dichloromethane. A separation funnel is used to separate the two liquids by the process of liquid-liquid extraction, which makes use of the solubility difference. The liquid with a high density represents the lower phase when the mixture is brought into the separation funnel, while the liquid with a lower density represents the upper phase. It is not possible to easily distinguish substances of similar densities using this approach. The method of saturating the high density phase with a suitable salt and increasing its density can be applied in such a situation. Or, by closing, the lid of the dividing funnel is shaken and the phases are separated. The gas emitted when shaking can cause changes in pressure. The lid of the separating funnel is opened to avoid this and the gas outlet is allowed. This method is continued until the gas outlet is completed. By waiting for a while, the phases are clearly separated. The lower phase is discharged from the funnel after the phases are clearly separated, before the upper phase reaches the tap stage. On the other hand, the upper stage, even if it is thin, has the potential of mixing with the upper phase and forming impurities. The upper stage can be isolated carefully with a pasteur pipette for this. To guarantee that all the material to be extracted goes into the organic phase, the same procedure is repeated three times. **Materials** - Dropping funnel - Erlenmeyer flask - Beaker - Filter paper **Chemicals** - Granulated coffee - Dichloride methane - Al₂O₃ or CaCl₂ - Tea bags - Na₂CO₃ **Experiment Preparation:** This study will try to remove caffeine from a solution prepared in water using tea leaves or coffee granules. **Figure 5.1. Differential Extraction** *Diagram of a separating funnel before and after extraction. The before image depicts the organic compound in water phase and the solvent in the separation funnel. The after image depicts the organic compound in the solvent phase (lower phase) and the water phase (upper phase) in the separation funnel.* **Steps for extraction:** 1. Tea and coffee solutions are prepared. It is transferred to the separation funnel so that it covers 1/3 of the volume of the separation funnel. Don't forget, it must be cold. 2. Add an equal volume of dichloride methane to the separation funnel and shake it vigorously. During shaking the separating funnel should be tilted slightly, its lid should be closed, it should be held with one hand so that the tap cannot be opened. It should be ensured that nobody is against the top of the funnel. The pressure created by rinsing must be reduced by opening the funnel lid once in a while. 3. After the substance to be separated into the organic phase, the funnel is placed in the ring to separate the two phases and waited until the phases are clearly separated. 4. After the phase separation is completed, the lower phase is transferred to the flask. 5. The process is repeated twice more for the aqueous phase. The extraction step is usually repeated three times so that more caffeine can be drawn. It is ensured that the organic matter is transferred into dichloromethane. 6. In the extraction of caffeine from tea, some tannins along with caffeine pass into the organic solvent. To separate it, it is removed by adding Na₂CO₃ to the solution. Tannin remains in basic solution. 7. After the extraction process is complete, the combined organic phases must be dried with a suitable dryer to remove any remaining water molecules in the phase. Al₂O₃ or CaCl₂ can be used for this. Depending on the amount of water remaining in the organic phase, the amount of desiccant to be added is determined. 8. The drying chemical is removed by filtration, while the organic solvent is removed by evaporation / distillation.