_1SB Acetaminophen Lab Report

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School

Arizona State University, Tempe *

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Course

235

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Chemistry

Date

Apr 3, 2024

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docx

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8

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Uploaded by MazikeenSmith

BHATT1 Acetaminophen Lab Report CHM 235: Wednesday, 7:30-10:20am, Room H 336; Hood 8 March, 31st, 2023 TA – Margaret Madsen Arizona State University SHREYA BHATT
BHATT 2 Abstract Acetaminophen, also known as paracetamol, is a widely used pain reliever and fever reducer. This lab report describes the synthesis of acetaminophen from p-aminophenol using acetic anhydride as the acetylating agent and phosphoric acid as the catalyst. The reaction was carried out at room temperature and the product was isolated by vacuum filtration and purified by recrystallization. The purity of the final product was confirmed by measuring its melting point and analyzing its IR spectrum. Melting points for crude and pure products were obtained, as well as percent yields of 159% and 71.22%, respectively. The IR spectrum showed bond vibrations similar to a spectrum of pure acetaminophen, which was another way of characterizing the sample. The IR spectrum showed characteristic peaks for the acetaminophen molecule, confirming the success of the synthesis. Introduction Acetaminophen, also known as paracetamol, is a widely used analgesic and antipyretic drug. It is a widely used over-the-counter medication for the relief of pain and fever. It is classified as an analgesic and antipyretic drug and is typically used to treat headaches, muscle aches, and fever. The chemical name of acetaminophen is N-(4-hydroxyphenyl)acetamide and its molecular formula is C8H9NO2. It is a derivative of p-aminophenol and is synthesized through the reaction with acetic anhydride and a catalyst, typically phosphoric acid or sulfuric acid. The reaction is below:-
BHATT 3 The synthesized product is typically a mixture of acetaminophen and unreacted p-aminophenol. Therefore, it is necessary to purify the product through recrystallization. Recrystallization is a common purification technique that involves dissolving the crude product in a suitable solvent and then cooling the solution to allow the crystals to form. The crystals can then be collected through filtration and dried to obtain a pure product. Experimental To synthesize acetaminophen, 0.149 g of p-aminophenol was mixed with 0.3 mL of acetic anhydride, 0.5 ml of water and 2 drops of phosphoric acid in a round-bottom flask. A magnetic stir bar was put into the mixture, and an air condenser was attached. The mixture was heated and stirred using a heat plate and the refluxing technique until all solids were dissolved. After 15 minutes, the flask was cooled so that it’s easy to touch , and the spin vane and air condenser were removed. The mixture was then cooled in an ice bath until crystals formed. Once the crystals were formed, the crystals were filtered using a Hirsch funnel and rinsed with cold water. The crystals were then weighed, crushed, and used for recrystallization, with a small sample collected for obtaining the melting point. The remaining crystals were dissolved in a 50:50 methanol-water solution and cooled to room temperature. The product was filtered again, and the recrystallized product was weighed. Once, the weighing was done the crystals were crushed, and used for obtaining the melting point and then was used for recording the IR spectrum.
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BHATT 4 Results Chemicals Weight (g) Melting Point (C) P-aminophenol in the beginning 0.149g We didn’t do MP for the beginning stage Crude Product 0.330g 181.4-183.5 C Pure Product 0.147g 169.8-170.9 C Percent Recovery of the product : (0.147)/(0.330)*100= 44.54% Moles of p-aminophenol: 0.00136534mol Moles of Crude product: 0.00218307mol Moles of Recrystallized product: 0.00097246mol Percent Yield: ( 0.00097246mol )/(0.00136534mol )*100= 71.22% % Chemical Yield of Crude product: (0.00218307mol )/(0.00136534mol )*100= 159% % Chemical Yield of Pure Product: ( 0.00097246mol )/(0.00136534mol )*100= 71.22% The table above shows the Melting point and weights of chemicals after every stage. And, below the table there are calculations of the % yields. Below is the copy of my IR Spectrum. Table with Peak Lables from IR Spectrum Sample Peak (cm-1 ) Specific Bond VibrationFunctional Group 3325.2 N-H Amide 3105.67 O-H Alcohol 1648.11 C=O Amide 1608.96 C=C Benzene Ring
BHATT 5 Discussion: Chemical synthesis involves breaking reactant bonds and forming new product bonds to create a new structure. Refluxing was used to condense vapors and supply energy to reactions for an extended period. Increasing the temperature produces activation energy that allows molecules to transition, breaking old bonds and forming new ones. Crystallization and recrystallization techniques were used to isolate and purify the new molecules. Melting point ranges were taken, with the crude product having a range of 181.4C-183.5C and the pure product having a range of 169.8C-170.9C, fitting within the range for pure acetaminophen (168C-172C). The crude product had a higher range due to impurities, so recrystallization was performed to purify the sample further, resulting in a smaller range for the recrystallized product. The percent chemical yield was calculated based on the number of moles in the crude and pure products, with a 159% yield for the crude product and a 71.22% yield for the pure product, leading to a 44.54% recovery of pure acetaminophen. The experiment demonstrated the importance of careful handling and precise measurements. An IR spectrum of the recrystallized product showed peaks at 1608.96cm-1, 1648.11cm-1, 3105.67cm-1, and 3325.2cm-1, corresponding to bond vibrations of benzene ring, C=O, O-H, and N-H. Overall, the experiment was successful based on the correct melting point ranges and IR spectrum. The source of error can be not drying the product fully and weighing it whe it was heavy that’s why crude product’s % yield is high. Conclusion The aim of the experiment was to synthesize acetaminophen through isolation, purification, and characterization to determine the sample's purity. The experiment was deemed successful based on the obtained melting points and the IR spectrum. The yields for the crude and pure product, as well as overall recovery, were not as expected because the crude product’s % yield was slightly
BHATT 6 higher than expected because of the error in the experiment. But, overall it was a successful experiment. Chemical synthesis is a valuable technique in a laboratory as it enables the production of a pure product from multiple reactants.
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BHATT 7 References Login . (n.d.). Weblogin.asu.edu. Retrieved April 1, 2023, from https://asu.instructure.com/courses/138989/files/58339968 Ch, N. H., & N, O. (2006). Synthesis of Acetaminophen p -Aminophenol Acetic anhydride Acetaminophen Acetic Acid . http://rene.souty.free.fr/IMG/pdf/ParacetamolProtocolFLORIDacetaminophen. pdf
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