The remainder of the crude product into a different 50 mL Erlenmeyer flask with a spatula. Kelsey measured 2 ml of ethanol in a 4. We dipped the flask in a mL beaker of warm water to dissolve the crystals. This only took a few seconds and no additional ethanol was needed to fully dissolve the crystals. Next, I measured 3 mL of warm de-ionized water into a 4. We covered the flask with a watch glass and set it on the table to cool to room temperature for 18 minutes. Since no crystals had formed, Dr.
Shriver tried to induce crystallization by using a spatula to scratch the inside of the flask. No crystals formed, so we placed the Erlenmeyer flask in another mL beaker with ice for six minutes.
The contents of the Erlenmeyer flask were milky, and crystals were not forming. Shriver reheated the flask over the hot water bath. We let it re-acclimate to room temperature. Shriver tried to induce crystals to form by adding some aspirin crystals from another lab group to the flask. He placed the flask on top of the ice in the mL beaker. After a few minutes, more crystals formed than in the previous attempt, but there were still not enough crystals to collect in a funnel.
Shriver again re-heated the flask over the hot water bath and added a few drops of de-ionized water to the flask. We allowed the flask to cool to room temperature for several minutes. At first, the contents of the flask continued to cloud up rather than form crystals. Once crystallization began, a large amount of crystals formed. We filtered the crystals using a Hirsch funnel as before. We placed the pure product in a pre-weighed vial 2.
We placed the vial in my drawer and covered it with a watch glass to dry for a week. The crystals looked small and white. The following week we weighed both vials containing the pure and crude crystals to calculate a percent yield.
We also used the melting point apparatus to obtain a melting point for both the crude and pure crystals. We increased the temperature on the melting point apparatus volts at a time. Finally, we took an IR of the pure crystals. This procedure was adapted from The Synthesis of Aspirin. The IR spectrum confirms the formation of aspirin as the product. The IR spectrum is appended. Profesional Associations:. Return to Scientific Advisory Board. John Chia. Medical Oncology.
Scientific Interests:. Aspirin as adjuvant therapy in established cancers Adoptive T cell therapy and Dendritic cell vaccines in the treatment of solid tumors Clinical Trial Design and Management. Declaration of Conflicts of Interest:. Lina Badimon. Pharmacology, Cardiovascular Disease. Cardio-metabolic diseases, thrombosis, atherosclerosis and ischemic heart disease.
Junbo Ge. Ruth Langley. Medical oncologist; trialist. Aspirin Gastro-oesophageal malignancy Transdermal oestrogen in the treatment of prostate cancer Trials methodology. Has received honorarium from Bayer. Andrew T Chan. Andrew T. The role of aspirin in the prevention of colorectal cancer and other cancers The role of the gut microbiome in colorectal cancer and other chronic gastrointestinal diseases, including inflammatory bowel disease and diverticulitis The role of diet and lifestyle in colorectal cancer and other chronic gastrointestinal cancers.
I received consultant Bayer and Pfizer, Inc. Mike Gaziano. I am a chronic disease epidemiologist with a particular interest in the roles that individual lifestyle choices diet, exercise, smoking , metabolic factors obesity, high cholesterol, and hypertension , and biochemical and genetic markers play on the risk of cardiovascular disease and other chronic illnesses.
In previous experiments, we used Fischer esterification reaction to produce some esters that we detected by odor. The current experiment uses, instead of glacial acetic acid concentrated acetic acid , another carboxylic acid derivative, acetic anhydride for ester formation. The advantage of using acetic anhydride is that you do not produce water which can be used for hydrolysis of the newly formed ester.
Concentrated phosphoric acid will be used to keep everything in the acidified, protonated state. Acetic anhydride is the preferred acid derivative to synthesize aspirin commercially because the acetic acid produced in this reaction can be used again, by converting it back into acetic anhydride. In a mL erlenmeyer flask, add 2 g salicylic acid put the flask on the balance, and zero it. In the hood, carefully add 5 mL of acetic anhydride severe irritant, handle carefully to the flask.
Stir the mixture with a stirring rod. Place the flask and its contents in a boiling water bath and stir untill all the solid dissolves. Remove the flask from the hot water and let it cool. Working in the hood, add 20 drops of water to the cooled mixture. Avoid breathing any of the vapors, which contain acetic acid, and are irritating.
When the reaction is complete, add 50 mL of cold water to the reaction mixture. Cool the mixture by placing the flask in an ice bath for 10 minutes. Louis ; Chemistry. Add 5 mL 0. H 2 SO 4 use a dropper, H 2 SO 4 is highly corrosive and swirl the flask gently until the salicylic acid dissolves. Heat the flask gently on the steam bath for at least 10 minutes.
Allow the flask to cool to room temperature. If acetylsalicylic acid does not begin to crystallize out, scratch the walls of the flask with a glass rod. Cool the mixture slightly in an ice bath until crystallization is completed. The product will appear as a solid mass when crystallization is completed. Add 50 mL of water and cool the mixture in an ice bath. Do not add the water until crystal formation is complete.
Vacuum filter the product using a Buchner funnel. You can use some of the filtrate to rinse the Erlenmeyer flask if necessary.
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