Ex- A - presence in crude and purified aspirin; therefore,...

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Experiment A: Synthesis of Aspirin In this experiment I measured my purified aspirin is 1.79 g and the percent yield is 47.48 %. This number is determined to be low, and this could be due to many reasons. When I transfered the crystal with a spatula, if not done carefully some crystal could be remained in the vial which contributing to low percent yield. Also, during the esterification reaction between salicylic acid and acetic anhydride in presence of sulfuric acid catalyst, the reaction might have not gone to completion due to short amount of time . So, another contributing factor for low percent of yield could be the effect of short reaction time . Moreover, aspirin is soluble in water, some aspirin could have been lost while washing with water. The purity of the crude aspirin and purified aspirin were checked by the ferric chloride analysis. The mixure of ferric chloride and salicylic acid shows a dark purple color. The salicylic acid should not be
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Unformatted text preview: presence in crude and purified aspirin; therefore, crude and purified aspirin should give no color result. and ferric chloride should give a yelow color. In my experiment, my ferric chloride and salicylic acid mixure was dark purple, crude aspirin result was light purple and purified aspirin result was faint purple color. Since my crude and purified aspirin give light purple color result, it means the presence of phynolic impurity in salicylic acid . Also, it may have a benzene ring and branched alcohol as a by product, which together may cause of faint purple color. That is way, my purified aspirin percent yield from salicylic acid to synthesis aspirin was low and the purified aspirin was faint purple color. Moreover, I have had problem with vaccum filteration which may not have properly filterated the mixures....
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This note was uploaded on 09/08/2010 for the course CHEM 113A at San Jose State University .

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