Experiment 8: Acetylsalicylic Acid Experiment
Monica Perez
Experiment 8: Acetylsalicylic Acid Experiment
01/25/2013
CHM Lab- 2211 Sec 0016
Instructor: Jennifer Reed
Introduction:
Commonly used as Aspirin, acetylsalicylic acid is an analgesic (pain reliever), which is one of the products of the esterification reaction between salicylic acid and acetic anhydride. This esterification occurs since the hydroxyl group from the salicylic acid reacts with acetic anhydride to form an ester. In this experiment, we will be able to recreate this acid catalyzed reaction, using sulfuric acid as our catalyst in order to produce acetylsalicylic acid and acetic acid. The final product of this reaction will be some crystals, which will be mainly composed of acetylsalicylic acid. In order to purify our products, we will have to add water to our crystals so that the acetylsalicylic acid can be dissociated from impurities. Using a technique called vacuum filtration, crystals will be held on a filtration paper while the liquid portion of reagents will drained into an Erlenmeyer flask.
To purify our crystals even more, we will have to perform a procedure called re-crystallization, using ethyl acetate as our solvent instead of water in order to prevent decomposition of our products, and then once again we will use vacuum filtration to separate the crystals from the solvent.
After we have finished with the experiment, we will be testing for the presence of salicylic acids in our crystals. Salicylic acid is a phenol and it will react with a mixture of Ferric Chloride by changing the color of the solution into a dark purple. If our crystals change color, it will mean that we still have some impurities and the melting point of the acetylsalicylic acid may be affected by the presence of these impurities.
Mechanism:
Results:
Table 1.1: Acetylation of Salicylic Acid Weight of Salicylic Acid | 2.00 g | Mass of Watch glass + filter paper | 32.43g | Mass of Watch glass + filter paper and product of re-
Experiment 8: Acetylsalicylic Acid Experiment
01/25/2013
CHM Lab- 2211 Sec 0016
Instructor: Jennifer Reed
Introduction:
Commonly used as Aspirin, acetylsalicylic acid is an analgesic (pain reliever), which is one of the products of the esterification reaction between salicylic acid and acetic anhydride. This esterification occurs since the hydroxyl group from the salicylic acid reacts with acetic anhydride to form an ester. In this experiment, we will be able to recreate this acid catalyzed reaction, using sulfuric acid as our catalyst in order to produce acetylsalicylic acid and acetic acid. The final product of this reaction will be some crystals, which will be mainly composed of acetylsalicylic acid. In order to purify our products, we will have to add water to our crystals so that the acetylsalicylic acid can be dissociated from impurities. Using a technique called vacuum filtration, crystals will be held on a filtration paper while the liquid portion of reagents will drained into an Erlenmeyer flask.
To purify our crystals even more, we will have to perform a procedure called re-crystallization, using ethyl acetate as our solvent instead of water in order to prevent decomposition of our products, and then once again we will use vacuum filtration to separate the crystals from the solvent.
After we have finished with the experiment, we will be testing for the presence of salicylic acids in our crystals. Salicylic acid is a phenol and it will react with a mixture of Ferric Chloride by changing the color of the solution into a dark purple. If our crystals change color, it will mean that we still have some impurities and the melting point of the acetylsalicylic acid may be affected by the presence of these impurities.
Mechanism:
Results:
Table 1.1: Acetylation of Salicylic Acid Weight of Salicylic Acid | 2.00 g | Mass of Watch glass + filter paper | 32.43g | Mass of Watch glass + filter paper and product of re-
Cited: Work Pavia, Donald L. A Small-scale Approach to Organic Laboratory Techniques. Belmont, CA: Brooks/Cole ; Cengage Learning, 2011. Print. “Acetylsalicylic acid (50-78 2).” Chemical Book. 2008. Web. 23 Jan. 20003. <http://www.chemicalbook.com/ProductMSDSDetailCB5114818_EN.htm> Literature Article: The melting process of Acetylsalicylic Acid single crystals The process of crystallization was studied by G. L. Perlovich and A. Bauer-Brandl in comparison to crystal growth of Acetylsalicylic Acid. The present work postulates an analogy to melting processes, looking at melting as nucleation. It is hypothesized that the melting process can be described similarly to crystallization assuming that nucleation of the liquid phase is followed by growth of the liquid phase in two or three dimensions respectively. By applying correlation analysis experimental data was obtained, explained by the layer structure of crystals of Acetylsalicylic Acid. By intergrading the DSC curves the fraction of material molten was calculated. This articled gave us some background information to better understand the results of this experiment and the reactions that occurred trough the experiment process.