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Experiment 5-Caffeine

Experiment 5-Caffeine - Jin Bae CHEM-241L Isolation of...

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Jin Bae CHEM-241L Isolation of Caffeine from Tea Performed: 10/05/2006 Written: 10/11/2006 Purpose The purpose of this lab is to understand the theories behind extraction and sublimation and use them to figure out the yield and melting point of products. The processes were used in extracting caffeine from tea. Reactions Gallic acid + CaCO 3 → Calcium gallate + H 2 CO 3 Tannin + CaCO 3 → Calcium salt of tannin + Ca 2+ + H 2 O + CO 2 Protonated Caffeine + CaCO 3 → Caffeine + H 2 CO 3 Tables of Reactants and Products Name Appearance M. point B. point Molar W Density Calcium Carbonate 825°C 100.087g/mol 2.83 g/cm³ Water 18.02°C 100°C 18 g/mol 1.0 g/cm³ Methylene Chloride −97°C 40°C 84.93 g/mol 1.325 g/cm³ Anhydrous Sodium sulfate 884°C 142.04 g/mol 2.68 g/cm³ Caffeine 237°C 178 °C 194.19 g/mol 1.2 g/cm³ Cellulose und. und. Gallic Acid 250°C 170.12 g/mol 1.7 g/cm 3 Catechin 290.27 g/mol Chlorophyll b 893.50 g/mol Procedure Part 1: Extraction First, 250 mg of calcium carbonate powder and 30mL of water were obtained. The beaker containing water was covered and heated on the sand bath. When it boiled,
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Jin Bae CHEM-241L tea bag was put in, and boiled until the Volume of the solution became 8~10mL. Pasteur pipet was used to transfer the concentrated tea solution. After adding 250mg of CaCO 3 into the conical tube, the tube’s contents were filtered through a Buchner funnel. The tea solution was extracted with 3mL of methylene chloride without forming emulsions.
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