Lab 1 Synthesis of Acetaminophen

Synthesis of Acetaminophen and Acetylsalicylic Acid, Extraction of Caffeine from Tea Aim: To synthesize crude acetaminophen from a sample of p-aminophenol and crude acetylsalicylic acid from a sample of Salicylic acid; to use an extraction method to remove pure caffeine from tea leaves. Experimental: Chemicals: Name Hirsch Funnel Structure P-aminophenol Solid, 109.1 g/mol Salicylic acid Solid, 136 g/mol Caffeine Solid, 194.19 g/mol Reagents: Water, Acetic anhydride, Phosphoric acid, Dichloromethane Set-up: Separatory funnel Filtration flask Physical Equipment: Procedures: A literature procedure was followed. The following is the actual sequence followed in the lab. A sample of 0.150 g (0.0013 mol) p-aminophenol was reacted in a test tube with 300 μL (2.93E-6 mol) acetic anhydride and 200 μL (1.10E-5 mol) distilled water. This mixture was heated in a sand bath until steam was evident. The test tube was then placed in an ice bath, the inside walls scratched with a metal spatula, and the crude acetaminophen produced was collected through vacuum filtration. A sample of 0.150 g (0.0012 mol) salicylic acid was reacted in a test tube with 400 μL (3.91E-6 mol) acetic anhydride and 5 drops of Phosphoric acid. This mixture was placed to warm in a hot water bath until all the solid had dissolved. The test tube was then cooled and the crystals of crude acetylsalicylic acid were collected by vacuum filtration. Tea bags were placed in a beaker of water and brewed. After cooling the tea was poured into a filter flask and 10 mL (1.177 mol) dichloromethane was added. The stopper was replaced, and the flask shook four times. Vapors produced were allowed to escape and process repeated until no more gas was formed. 10 more milliliters were added to the funnel and the mixture was allowed to settle. The bottom layer of liquid was titrated out of the funnel and into a beaker, and this was vacuum evaporated to remove excess water from the crude caffeine product. Chemical reaction/mechanism + Data: A sample of 0.166 grams (0.0013 mol) of p-aminophenol was converted to 0.0676 grams (6.19E-4 moles) of crude acetaminophen with a crude yield percentage of 34.38%. Comparison using an IR spectrum confirmed the identity of the product, though the purity was not confirmed by melting point. A sample of 0.015 grams (0.0001 mol) of salicylic acid was converted to 0.510 grams (0.0028 mol) of crude acetylsalicylic acid with a crude yield of percentage greater than 100%, uncovering impurities, unreacted material, and moisture in the sample. A sample of two tea bags measured to weigh 5.232 grams (0.061 mol) was used to extract 0.0414 grams (2.13E-4) of caffeine with a percent isolation of 0.34%. IR spectrum analysis confirmed the identity of the crude caffeine product. Results: Experiment: Starting material weight Product material weight Tylenol 0.166 g p-aminophenol 0.0676 g acetaminophen Aspirin 0.015 g salicylic acid 0.510 g crude acetylsalicylic acid Tea/caffeine 5.2320 g Tea bags 0.0414 g crude caffeine Discussion: The procedure was successful in its aim of synthesizing crude acetaminophen from the original sample of p-aminophenol. The produced substance was a whitish-pink powder that had dips and peaks in its IR spectrum reading matching that of the Tylenol standard, despite these dips and peaks being of different amplitudes. This confirms that the crude acetaminophen was indeed the substance produced, and that all starting material had reacted. The only issue occurring during the procedure was the sample taking extra time to crystallize in the test tube, a problem solved by adding cold water and scratching the inside of the test tube with a metal spatula. The quantity of crude acetaminophen collected was minimal due to additional cold water added during the experiment, explainable by the compound’s solubility in water. The theoretical yield for the synthesis of acetaminophen was determined to be 0.1966 grams (.0013 mol). In the synthesis of Aspirin experiment, the aim of synthesizing crude acetylsalicylic acid from salicylic acid was unsuccessful, based on the peaks and dips of the IR spectrum. Upon viewing the graph of the sample and comparing to that of an Aspirin standard. This could have been the result of the solid not being fully dissolved when the test tube was being heated. The theoretical yield for the synthesis of aspirin was found to be 0.020 grams (0.0001 mol), however the percent crude yield was inconclusive due to the sample containing some of the starting material. In the extraction of caffeine from tea experiment, the aim of removing a quantity of crude caffeine from brewed tea was successful. The caffeine experiment had a theoretical extraction yield of 11.96 grams, and a percent isolation of 0.346%. There was an emulsion that formed during the separating of the tea and dichloromethane, but it did not drastically change the results collected as data. The IR spectrum confirmed that crude caffeine was produced with minor impurities. Conclusion: The aim of the synthesis of crude acetaminophen experiment was to synthesize a crude sample that matched that of a sample standard of Tylenol, which was confirmed through IR spectrum analysis. The only significant issue occurring was time taken for the crude sample to form. The aim of the synthesis of acetylsalicylic acid experiment was to synthesize a sample of crude Aspirin from salicylic acid, which was unsuccessful upon reviewing the readings from the IR spectrum. The aim of the extraction of caffeine from tea experiment was to do just that. The extraction of crude caffeine from a sample of brewed tea was successful with minor impurities, as confirmed by the IR spectrum. Reference: 1. Organic laboratory Manual, Shanbhag & Veliz, Page 15-23, Nova Southeastern University, 2012 Questions 1. Crystallization depends on the induction of the solute by lowering the solubility of the solution. The lower the temperature causes lower solubility, which forces acetaminophen to precipitate out of the solution. 2. The water was used to maintain a controlled temperature at 100°C, since the water has a boiling point of 100°C. The addition allows the reaction to be carried out at a reliable temperature. 3. Minimizing the amount of water reduces the chance of contamination from impurities in the solvent. 4. 0.180 grams and 0.0012 moles C8H9NO2 5A. In every organic synthesis some of the starting material will remain in the reaction mixture even after completion. 5B. Organic reactions produce some unwanted byproduct which contributes to impurities. 6. 1A. B. CH3CH2CH2CH2COOH + CH3CH2OH C. CH3CH2CH2CH2COOCH2CH3