Organic Chemistry Experiment 10 Synthesis Of Aspirin

Organic Chemistry Laboratory – CH 200 (2014-2015) Experiment 10

Synthesis of Aspirin

Justin Gaña, Jamilette Guiam, Angelica Jimenez, and Joanna Jusay*
Department of Biological Sciences, College of Science
University of Santo Tomas, España Street, Manila 1051

Date Submitted: November 7, 2014

Abstract The synthesis of aspirin was remodeled and revised for a small scale experiment. An esterification reaction from the combination of salicylic acid and acetic anhydride with the presence of an acid catalyst produced acetylsalicylic acid (aspirin) and acetate. Purification of the crude aspirin was done through a technique called crystallization, wherein both the single solvent and mixed solvent methods were utilized. The percent yield

Since petroleum benzene it the least polar among the solvent, aspirin would not dissolve even if it was subjected to heat. Usually, compounds that have functional groups that can form hydrogen bonds, for example –OH, -NH, -COOH, -CONH, will be more soluble in hydroxylic solvents such as water or methanol than in hydrocarbon solvents such as toluene, hexane, or benzene (Pavia, Lampman, Kriz, & Engel, 1999). Since aspirin has four oxygen atoms that form hydrogen bonds and the oxygen atoms are more electronegative thereby pulling more electrons, this gives aspirin more polarity than petroleum benzene although it is less polar than the other solvents. In increase in temperature would result to an increase in solubility. Aspirin in water under cold conditions should be insoluble since it was used for the recrystallization of the crude aspirin and that aspirin is more polar than methanol because aspirin contains a carboxyl

This could solved by careful attention to the temperature of the solvent. Also the time of the Erlenmeyer flask in the hot bath during the synthesis of aspirin could have been more than 10 minutes which could have led to more impurities. Also some of the crude aspirin fell on the table. This could be also a factor for a low percent yield. Careful transfer and keen observation is recommended and could possibly lead to a higher percent yield. Proper knowledge of which solvent to use would also lead to a better yield.

References
(n.d.). Retrieved from http://www.chem.latech.edu/~deddy/chem104/104Aspirin.htm
(2014, November 06). Retrieved from Aspirin Foundation: http://www.aspirin-foundation.com/what/chemistry.html
Bettleheim, F. &. (2001). Laboratory Experiments for Organic and Biochemistry, Fourth Edition. New York: Harcourt College Publishers.
Eikelboom, J. S. (2012). Aspirin. Circulation, e438-e442.
Fessenden, R., Fessenden, J., & Feist, P. (2001). Organic Laboratory Techniques, 3rd Edition. Canada: Brooks/Cole.
Klein, D. R. (2012). Organic Chemistry. Massachussetts: John Wiley & Sons,