4A Extraction & Sublimation

4A Extraction & Sublimation - Phil Pearson Rachael...

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Phil Pearson Rachael Rosales Roshni Sheth Extraction and Sublimation of Caffeine from Tea Leaves A. Intro In this experiment, caffeine was extracted from tealeaves then purified using sublimation. An organic solvent extraction was performed in this experiment. The solvent methylene chloride was used because it has a high affinity for caffeine due to both compounds’ non-polar nature. Several small extractions are performed during this type of extraction because a series of small extractions are much more efficient than one large extraction. Once the extracted compound is separated from the mixture it can be dried, where it can be further purified. To purify the caffeine in this experiment, a sublimation procedure was performed. Sublimation occurs when a substance goes directly from a solid to a gas skipping the liquid phase. Sublimation has several major advantages over other purification methods. Some of those advantages include: no solvent is needed; it can be performed at low temperatures, especially under vacuum; loss of material due to handling is low; and it readily separates nonvolatile impurities. Once the compound is purified, its melting point can be taken to test the quality of the purification. Caffeine is a psychoactive stimulant drug. In humans it restores alertness and wards off drowsiness. It is in many different types of drinks such as coffee, tea, and soft drinks. Caffeine is the world’s most widely used psychoactive drug.
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Rachael Rosales Roshni Sheth Caffeine B. Experimental Reagent Physical Properties Tea Amount used: 2-4 g Water (H 2 O) Molecular weight: 18.01528 g/mol Density: 0.997 g/mL (25 o C) Melting point: 0 o C Boiling point: 100 o C Sodium carbonate (Na 2 CO 3, anhydrous) Molecular weight: 266.2731 g/mol Density: 2.54 g/cm 3 Melting point: 851 °C Boiling point: 1600 °C Amount used: 2 g Sodium chloride (NaCl) Molecular weight: 58.443 g/mol Density: 2.165 g/cm 3 Melting point: 801 °C Boiling point: 1413 °C Amount used: ~0.4 g
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This note was uploaded on 06/28/2011 for the course CH 236 taught by Professor Nikles during the Fall '09 term at University of Alabama at Birmingham.

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4A Extraction & Sublimation - Phil Pearson Rachael...

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