Removal of Caffeine from Tea Leaves Advantages Caffeine can be soluble in boiling water and as a result it is very easily extracted by tea luggage by steeping in hot water. This process leaves behind the water insoluble portions of the tea bag. However , water extracts more caffeine, thus a final splitting up is done with an organic solvent that will break down primarily caffeine. The organic and natural solvent utilized in this try things out is Dichloromethane (CH? Cl? ). Dichloromethane is less extremely than water and this difference in polarity allows the separation.
Extraction of the tea with the Dichloromethane, followed by evaporation of the organic solvent leaves crude caffeine, which on sublimation brings a relatively natural product. Sublimation is the move of a element from the solid phase right to the gas phase devoid of undergoing advanced liquifications. This method is favored over recrystallization because it is better at removing impurities. Experimental For this removal experiment two bags of tea were used, which is approximately 5 grams of tea. Drinking water was warmed in a small beaker until it began to boil.
It absolutely was then taken off heat and 2 grams of Na2CO3 was added and dissolved. Finally the loose tea was added to the water and in order to steep to get 5 minutes. Following 5 minutes the mixture was put through a suction purification. A suction funnel was secured over the suction flask with the vacuum lines. No filtration system paper was used because the tealeaves were incredibly course. After that 400mg of NaCl was added and dissolved. The perfect solution is was after that cooled in an ice bathtub. The solution was then transferred into a separatory funnel and was cleaned 3 times employing 5 cubic centimeters portion of CH2Cl2.
CH2Cl2 created a separate part on the bottom of the flask and was used up into a twenty-five ml flask after each wash. Every single wash was gently swirled to prevent emulsion. The combined washes had been then dried using little portions of Na2SO4 two times to remove virtually any water. A suction flask was acessed and the CH2Cl2 was put into the flask and the Na2SO4 was forgotten. A small test was considered for evaluation with genuine caffeine on the TLC plate. Then the suction flask with the CH2Cl2 was placed in a minimal temperature warm water bath with a boiling stay with boil all of the CH2Cl2 aside eaving just caffeine. The suction flask was in that case reweighed to determine the weight in the caffeine removed. The flask was then covered with parafilm and the sublimation was done seven days later. The Sublimation equipment was put together consisting of the filtration flask with our caffeine extract in it, using a test conduit securely placed 10-15mm above the bottom of the flask. It was secured with a plastic stopped and parafilm. A pippet bulb was placed over the provide of the suction flask. The flask was then put into a fine sand bath having a temperature among 200-220 deg Celsius.
The test tube was filled with solid ice and water was removed and even more ice was added occasionally throughout the sublimation process. As the sublimation took place the caffeine get from the bottom from the flask started to collect as being a film on the bottom of the check tube. The method was completed when forget about caffeine was left in the flask. The test tube was removed plus the collected caffeine was scraped off and weighed. The melting stage of the pure caffeine was also measured. Results and Discussion Through the extraction try things out 0. 12 grams of impure caffeine extract remained in the suction flask. This value could possibly be lower than expected because through the extraction there were some emulsion in the seperatory funnel during each wash. Some of our extract might have been lost because of this. Also whilst boiling the CH2Cl2 a small amount from the solid extract remained on the boiling stick. On the TLC plate the tea draw out traveled nearly the same length as genuine caffeine. The Co-spot journeyed the exact same length as the pure caffeine. The Rf values to get caffeine and the Co-spot were 0. sixty six. The Rf value of the tea remove was 0. 133. Right after in the places could be because of some pollutants in the tea extract and differences in focus of each place. After the sublimation 0. 003g of natural caffeine was scraped from the test tube. The burning point array of the genuine caffeine was tested and located to be 237-239 degrees C. The actual melting point of caffeine can be 238. Summary The results of the TLC plate confirmed that the tea extract was very close to the sample of pure caffeine.
It was somewhat off perhaps due to impurities that remained in the tea extract. The caffeine considered in the flask after the liquid-liquid extracted was 0. 012g, which was different from the weight of the caffeine obtained following the sublimation. This kind of difference was likely due to impurities inside the caffeine ahead of being filtered by sublimation. The caffeine that was extracted from your sublimation experiment had a burning point of 237-239 levels Celsius, which is the same as the reported value to get caffeine.
The sublimation led to having a totally pure get of caffeine. Questions 1 ) Why is sodium chloride put into the tea solution just before extraction with CH? Craigslist? Sodium chloride pulls the water from the organic layer and also helps push the organic and natural compound into the organic part. 2 . Could you have utilized ethanol rather than CH? Cl? to extract the caffeine? Why or why not? Zero, because ethanol and normal water are miscible in one another. They will not separate into unique layers, and so a less polar solvent like CH? Cl? is much better at separation and removal of caffeine from normal water.. What is the purpose of adding sodium carbonate for the flask inside the brewing step? Sodium carbonate is a bottom and if added a medications will form and the stable material then can be removed. 5. At twenty-five degrees C, 1 . 0 g of caffeine will certainly dissolve in 47 cubic centimeters of drinking water, in eight. 1 milliliters of chloroform, in eighty six mL of benzene, or perhaps in 370 mL of diethyl azure. Calculate the solubility (in grams/ 100mL) of caffeine in these several solvents. Determine the rupture coefficient of caffeine between water and each of the other three solvents.
Which of these three organic solvents would be the best choice for extracting caffeine from an aqueous solution? In pieces (partition coefficient) = / a) Solubility of caffeine in water= 2 . 13 (g/100 mL) b) Solubility of caffeine in chloroform= 12. thirty-three ( g/100 mL), Kd=5. 88 c) Solubility of caffeine in benzene=1. two (g/100 mL), Kd=. 13 d) Solubility of caffeine in diethyl ether=. twenty-eight (g/100 mL), Kd=. 56 Chloroform will be the best choice to get extracting caffeine from a great aqueous option.