Water Extraction Is Different Than Brewing Coffee

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1. The first step of water extraction is different than brewing coffee because only a small amount of water is used. Additionally, the same bag was brewed twice as opposed to one time. Both of the previous processes are done in order to get a more concentrated sample of caffeine. The hot water extraction is similar to brewing coffee because hot water is used so that the caffeine will be more solubilizable, however a larger amount of water is used to dilute the amount of caffeine. Another similarity is that when the hot water extraction has concluded, the coffee contained caffeine and other impurities such as tannins and cellulose. 2. The potassium carbonate used in this experiment is used as a base and reacts with the gallic acid in in the carboxylic acid of the hydrolyzed tannins. When the potassium carbonate reacts with the tannins it produced potassium salts that are water soluble. Also the phenol groups in the catechin react with the potassium carbonate to form salts that are water soluble. When the salt is formed this separates the aqueous layer from the organic layer in the centrifuge tube once they are combined. 3.…show more content…
Water is used because it also removes tannins, caffeine, and some of the pigments in tea. The caffeine and tannins are also soluble in water because of their similar polarities. The organic layer consists of the dichloromethane, cellulose, and caffeine. The dichloromethane was used as the organic solvent. This was used as the solvent because cellulose and caffeine are soluble in it because they all have similar polarities. The dichloromethane was also used to help purify the caffeine even more because tannins are not soluble in it. Water and dichloromethane are also used as solvents because when both of the solvents are combined, and centrifuged, they will not mix because water is polar and dichloromethane is nonpolar. Therefore, once the layers are separated there should only be caffeine in the dichloromethane
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