Experiment 4: Solid-Liquid Extraction and Sublimation of CaffeineIn this experiment caffeine was extracted from tea using dichloromethane and liquid-liquid extraction. After separating the two layers, the dichloromethane extracts were heated until we obtained dry, crude caffeine. The crude caffeine sample was then purified using sublimation techniques. By converting the crude solid into a gas, we were able to condense the caffeine vapor exclusively. The goal of this experiment was to gain as much pure caffeine as possible through these newly introduced techniques.Starting with a 2.596g tea bag, we made a dark black tea. When we added the dichloromethane to the solution, and separated the two layers using a centrifuge, the organic layer was a clear, slightly yellow color. We ended up with a total of 19mL of aqueous solvent and 8mL of dichloromethane (organic solvent). The slight yellow tint in the dichloromethane was reflected in our 0.021g crude caffeine sample. After sublimationwe were left with 0.0081g of a "pure" white caffeine. These values suggest that we lost a fair amount of caffeine in the sublimation process.Assuming there is 55mg of caffeine in each tea bag, we got a recovery of 14.7% and a partition coefficient of 1.47 if we use our crude sample mass.K = (g per mL of organic solvent)/(g per mL of aqueous solvent). Comparing our partition coefficient to the accepted 1.8 value, we can conclude that separating the two layers using a pipette was not a very efficient process and therefore left a significant amount of caffeine in the aqueous solvent.Using our "pure" caffeine we observed a melting point range of 208-216°C. This is compared to the actual melting point range of 235-238°C (Caffeine, 2009). This would suggest a significant amount of impurities, however, our IR spectrum suggested otherwise. Our IR spectrum looked very similar to those from online journals such as those from the National Institute of Standards and Technology (Caffeine, 2009). Therefore, we were most likely successful in recovering a close to pure product and got a bad melting point reading due to thermometer lag.Possible sources of error might include failing to get all of the caffeine out of the tea, leaving significant amounts of caffeine in the aqueous solvent after the centrifuge, losing caffeine during the sublimation process, or (as stated earllier) experiencing thermometer lag when recording the melting point range. The first three sources of error would result in low yields of caffeine, while the last one would give low melting point ranges and thus suggest false level of impurities."Caffeine." Caffeine. National Institute of Standards and Technology, 2009. Web. 19 Feb. 2014.