Syntheis and spectral analysis of aspirin DR Hamilton (2) PDF

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Summary

Aspirin /salicylic experiment lab assignment...

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Versi Rukshana Versi Dr Hamilton CHM2211L 3/20/2021 Synthesis and Spectral Analysis of Aspirin A) IR Spectrum: IR Spectroscopy is helpful in determining organic functional groups. 1) C=O of carboxylic group attached to benzene ring appears at 1690-1680 cm^-1 2) C=O of Ester group appears at 1735-1750 cm^-1 3) Aromatic C=C stretching frequency is at 1600-1500cm^-1 •

B) Molar Mass of Salicylic Acid=138.121

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Mass given= 2.027

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Moles=

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M of Aspirin=180.58

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Mass given= 2.357

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Moles =

2.027/138.121=0.01467 Moles

2.357/180.158=0.01308 Moles

Theoretical Yield 138.121 gm of salicylic acid give =180.138gm Aspirin 2.027 gm of salicylic acid =180.158*2.027/138.121=2.6439 Actual Yield

2.357

Percent yield

2.357/2.6439 *100=89.14%

Q2) a) Write an equation for a reaction that might form salicylic acid during the workup of the product.

Versi 2 Aa) Kolbe’s Schmidt reaction. When sodium phenoxide is heated with CO2 at about 400K under a pressure of 6-7 atmospheric, a carboxyl group is introduced mainly at ortho position and sodium salicylate is obtained as major product. This on acidification yield salicylic acid. B) Tell how you could prevent or reduce the contamination of your product due to this reaction. Ab) Contamination can be reduced or prevented by seeing that large amount of moisture is not present in the reaction mixture. Salicylic acid is stronger than aspirin because it contains two acidic functionalities one is carboxylic acid group and other is phenolic. Add distilled water to remove acetic anhydride and treat with ethanol-water to remove salicylic acid, recrystallize the product and keep it in dry and cool place to avoid moisture and heat. Q6) Write a detailed mechanism for the reaction of salicylic acid with acetic anhydride, showing clearly the function of the catalyst, sulfuric acid. A6) Mechanism on Chem Doodle Aspirin is a trade name for acetylsalicylic acid, a common analgesic. Acetylsalicylic acid is an acetic acid ester derivative of salicylic acid. Aspirin (acetylsalicylic acid) is an aromatic compound containing both a carboxylic acid functional group and an ester functional group. Aspirin is a weak acid that is only slightly soluble in water. Aspirin can be prepared by reacting salicylic acid and acetic anhydride in the presence of an acid catalyst....