The Synthesis of Aspirin and Wintergreen Oil Lab Report PDF

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The Synthesis of Aspirin and Wintergreen Oil By: Carly Cochran October 10th, 2019 Introduction

Experiment 5, Synthesis of Organic Compounds: Aspirin and Wintergreen Oil, takes a deeper look into esterification reactions when using Salicylic Acid. An esterification reaction occurs when a carboxylic acid and an alcohol react under the presence of heat and a catalyst. In this experiment salicylic acid reacted with acetic anhydride to form aspirin and with methanol to form Wintergreen Oil. This process required suction filtration and recrystallization. Suction filtration is a fast way to separate a liquid from a precipitant, or a solid. By placing a small filter into a funnel and hooking up a vacuum hose to a filter flask, the liquid above the filter will move into the filter flask leaving the solid behind. Recrystallization is the process of dissolving crystalized results and allowing the product to crystalize again. This washes out impurities and allows for a pure final product. RxN Scheme

Synthesis of Aspirin

Synthesis of Wintergreen Oil

Experimental

The experiment was split into two parts, part a and part b. Part A called for 5.00g of salicylic acid and 6.0 mL of acetic anhydride be added together in an Erlenmeyer flask. Once mixed eight drops of concentrated sulfuric acid was added and the flask was then secured with a ring stand and lowered roughly a half an inch into a beaker filled slightly more than halfway with water and brought to a boil. The mixture was stirred as the heating process continued until the substances were dissolved completely. The flask was then sat in an ice bath until crystallization was complete. The content of the flask was then poured slowly into the suction filtration system until almost all the liquid had been removed from the crystals. After the crystals were rinsed with water the substance was measured and it showed that 6.67g of crystals had formed. The recrystallization process then began by dissolving crystals in a small amount of ethanol in a beaker. The beaker was placed on a hot plate and brought to a boil in a few minutes, dissolving the crystals completely. The beaker was then placed into an ice bath. Due to a lack of time the recrystallization process was not completed. The substance in the beaker was not fully crystalized but poured into the suction filtration system and rinsed with water. The amount of aspirin that had formed was 0.49g.

Part B called for the mixture of approximately 2mL of methanol and a small amount of salicylic acid in a beaker. Once combined 10 drops of sulfuric acid was added and the beaker was placed in a warm water bath. After 2 minutes reaction was complete. Results and Discussion

The crude product was that of the first crystallization. Before suction filtration the product was blue/teal, appeared to have a foam texture. Any unreacted acetic anhydride was reacted with ice water and formed acetic acid.

After the suction filtration process, it was light blue and resembled characteristics similar to kinetic sand. When getting the pure product, the liquid with the dissolved crystals was light blue. Although the process was not fully completed, what was crystalized and underwent the suction filtration closer to white and was fluffy. A smaller amount was weighed because the process didn’t have time to crystalize completely. However, a smaller weight was expected. The recrystallization process eliminated impurities that could be found and were measured in the crude product, meaning the pure product should weigh less. Actual yield is the measure of the actual amount of the product that was received at the end of the experiment. Theoretical yield is the measure of what was hoped to be received at the end of the experiment. Actual yield is usually less than theoretical yield because the theoretical yield represents the amount of product formed in a perfect experiment. In this experiment the actual yield was less than the theoretical yield for the pure product because it didn’t complete the

recrystallizing step. The percent yield can be more than 100%. In the case of this experiment it just meant that the crystals weren’t completely dry yet. Theoretical Yield: 1 mol 36.2 mmol salcylic acid 1 mol Aspirin 180.157 g x x x ❑ 1 mol 1 mol SA 1000 mmol

= 6.52g

6.76 g x 100=Percent Yeild of crude product =103.68 % 6.52 g 0.49 g x 100=Percent Yeild of pure product =7.515 % 6.52 g

The wintergreen oil smelled like peppermint. The synthesis of wintergreen oil and the synthesis of aspirin are both esterification reactions. They are performed together to show how salicylic acid can react under the presence of heat and form esters. Conclusion

The Synthesis of Organic Compounds: Aspirin and Wintergreen Oil was a success. While the results may not have been perfect, the concept and purpose of the experiment was followed through. While not all the pure aspirin was able to form, some was proving that a purer form of a substance can be achieved by recrystallization. Although the actual yield of the crude product was imperfect, it did prove that suction filtration is helpful in separating a solid from a liquid. Time did prove to be an issue in the experiment and may be altered in future experiments.

Measuring things more exactly in the experiment may be helpful in getting more exact results, results closer to the theoretical yield.

Citations Clark, Travis B. “Experiment 2 Dyes and Dyeing.” CHM 1020 Elementary Organic Chemistry , edited by Kirby A Underwood, Wright State University , pp. 35–49....