Synthesis of Acetaminophen Essay
Acetaminophen was first introduced in 1955 (Richman, 2004). It is an over-the-counter drug that relieves pain and reduced fevers. Acetaminophen is considered an alternate to aspirin since it does not irritate the stomach (Richman, 2004). It also has very low toxicity is it is used properly. Acetaminophen is cheap and easily obtainable from any pharmacy. Acetaminophen is created when the amine group of p-aminophenol is acetylated by acetic anhydride. This creates an amide functional group and the by-product of this reaction is acetic acid.
The crude acetaminophen will form as a white solid after the acetylated reaction. To turn this crude acetaminophen into a purified form, the recrystallization technique will be used. The recrystallization technique is when the solid is dissolved and forced to precipitate as a crystal solid later on. The crude solid is dissolved through heating with a small amount of solvent, in this case, deionized water. The solution is then cooled to room temperature and later put into an ice bath which is when the crystals form.
These crystals obtained are more pure since the impurities are dissolved in the cold solution. When cooling, the solution should remain undisturbed. The purpose of this experiment is to determine the melting points of the crude and purified form of acetaminophen using a MelTemp melting point apparatus. Using capillary tubes, samples of the crude and purified solid will be tested. If the experiment is done properly, the crude solid should dissolve faster than the purified solid of acetaminophen. One must wear goggles and gloves at all times while working with acetic anhydride as it is corrosive. ttp://de. academic. ru/pictures/dewiki/83/Synthesis_of_paracetamol. png http://de. academic. ru/pictures/dewiki/83/Synthesis_of_paracetamol. png Procedure
The experimental procedure used for this experiment was outlined in the CHEM 123L lab manual, Experiment #1, Synthesis of Acetaminophen, pages 12-15. A slight change was made to the one material that was used. Instead of a 100mL round bottom flask a 50mL round bottom flask was used. Other than that, all steps were followed accordingly. Experimental Observations * Initial p-aminophenol: 3. 00g 36mL of deionized water was added to the Erlenmeyer flask for the recrystallization technique. Table 1: Outcomes of Crude and Purified Solids Crude| Purified| Erlenmeyer Flask| Total Mass| Mass of Solid| Erlenmeyer Flask| Total Mass| Mass of Solid| 92. 68g| 96. 28g| 3. 60g| 92. 82g| 95. 66g| 2. 84g| Melting Point: 162 °C| Melting Point: 164 °C|
*This table shows how much of the solid was obtained after the reaction along with their boiling points. This table can be used to see the difference between crude and purified solids. Results and Calculations -Aminophenol + Acetic Anhydride Acetaminophen + Acetic Acid C6H7NO(S) + C4H6O3(l) C8H9NO2(s) + C2H4O2(aq) Crude| Purified| | | | | Discussion The objective of this experiment was to find the melting points of the crude and purified solid. After conducting the experiment, it was found that the crude solid melted faster than the purified solid. Our values showed that our samples melted at a slightly lower temperature than what the Merck Index had stated. The Merck Index said that the melting point varies from 169°C -170°C. The melting points we had observed were from 162°C -164°C.
This might be due to the fact that this experiment was not done under perfect conditions. Also, what we found in terms of how much acetaminophen was obtained, was that the crude product was obtained in larger amounts than purified. From the initial amount of p-aminophenol, which was 3. 00g, we achieved 3. 60g of crude solid and 2. 84g of purified solid. This solidifies the theory that the impurities would have dissolved in the deionized water which is why the mass is lower for the purified solid. There were very few, if any, errors made during this lab. Questions 1. )
If 20 mL of water were added for every 1g of crude product then crystallization would occur in less quantity or not occur at all. As the solution is dissolved, heated, and later cooled, the impurities of the solution remain in the solution. As more solvent is added, more of the product will remain in the solution rather than crystallizing; hence, a much lower yield would be obtained. b) If 5mL of water were added for every 1g of crude product then one of two things would happen; the solid would not dissolve or the impurities would still be present within the product.
The solvent is used to dissolve all the impurities of the crude product and if less solvent is available, the impurities would remain within the product. c) If room temperature solvent was used rather than cold solvent then more of the product will remain in the solution. As temperature increases, solubility also increases in most cases, which would keep some of the product dissolved resulting in a lower yield. 2. a) An organic compound is any compound that contains carbon, generally, are large chains of carbon that are covalently bonded. They can be gaseous, liquid or a solid (Seager; Slabaug, 2004). ) An amine is an organic compound/functional group that is derived by replacing one or more of its hydrogen atoms in ammonia by another organic group. You may have a primary, secondary or tertiary amine according to how many hydrogens are reduced (Hine, Elizabeth, 2008). c) An amide is an organic compound/ functional group that contains nitrogen and is considered to be a derivative of ammonia. It is grouped with a carbonyl (Newton, 2004). 3. Tylenol got its name from p-aminophenol. Since tynenol is made up of p-aminophenol the name can be found within the word, “paraceTYLaminophENOL (Richman, 2004).
The p-aminophenol is a crucial part to the creation of acetaminophen; hence, it was appropriate to name the brand “Tylenol”. Conclusion The purpose of this experiment was to determine the melting points of the crude and purified sample of acetaminophen. Through this, it was found that the crude solid melted faster than the purified solid that is what is supposed to happen ideally. The recrystallization technique was also proven affective since the mass of the solid decreased showing that the impurities were dissolved in the solution.
This experimental method is highly effective as the values are generally accurate. There are not many areas where one can make mistakes as well which compliment the efficiency of this experiment. The main error possible in this experiment would be reading the temperature at which the solid melts; however, that is not in the experiment, as that would depend on the experimenter. Overall, this experiment was constructed fairly well giving values that solidify the theories behind this experiment.
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