Exp 2 - “centrifugation” Safety caution 1 Keep balance...

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TA: HSIEN-PO CHIU Sep 25 & 27, 2007 Exp 2. Separation the components of “Panacetin” Principle 1. Panacetin contains aspirin, sucrose, and an unknown compound that may be either acetanilide or phenacetin. These substance can be separated by their different characteristics: * Sucrose is insoluble in dichloromethane (DCM) * Aspirin, acetanilide, and phenacetin are soluble in DCM, but insoluble in water. * Aspirin reacts with NaOH to form a salt, insoluble in DCM but soluble in water. * Acetanilide and phenacetin are not converted to salts by NaOH HN O O O COOH O HN O Aspirin Acetanilide Phenacetin Acetaminophen OH HN O 2. If a substance has different solubility in two immiscible liquids, it can be transferred from one liquid to the other by shaking the two liquids together. This process is called “extraction”. 3. The conversion of a volatile liquid to vapor at or below the boiling point of the liquid is called “evaporation”. 4. Separating different phases from one another by centrifugal force is called
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Unformatted text preview: “centrifugation”. Safety caution 1. Keep balance for centrifuge machine 2. Use water bath rather than direct heating for evaporation 3. Make sure the cap off while evaporation/heating in process Microscale procedure : follow procedures on p.33-34 Keep unknown compound in the drawer for the next experiment Result 1. Weight of panacetin used 2. Weight of sucrose 3. Weight of aspirin 4. Weight of unknown compound 5. Total mass of recovery 6. Percentage of recovery 7. Percent composition Q&A 1. In the separation of panacetin, which compound was insoluble in dichloromethane? (A) aspirin (B) acetanilide (C) sucrose (D) Phenacetin 2. What will happen if you extract the solution of aspirin and acetanilide in dichloromethane with an aqueous solution of sodium hydroxide? (A) no chemical reaction occurs (B) acetanilide goes into the aqueous layer (C) aspirin goes into the aqueous layer (D) Both aspirin and acetanilide go into the aqueous layer...
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