How to Make Aspirin – Acetylsalicylic Acid
Aspirin, also known as acetyl salicylic acid, is the most widely used drug for self-medication
in the world. The usual tablet contains about 325 milligrams of acetyl salicylic acid and a small amount of inert
binding material such as starch. Aspirin can relieve pain, lower fever, and reduce inflammation. Over four million
pounds of aspirin are manufactured in the United States each year. Now you can make some too, or at least know
how in case you are ever on Jeopardy.
1. Accurately weigh 3.00 grams of salicylic acid and transfer to a dry Erlenmeyer flask.
2. Add 6 mL of acetic anhydride and 5 to 8 drops of 85% phosphoric acid to the flask.
3. Swirl the flask gently to mix, then place the flask in a beaker of warm water for 15 minutes.
4. While the mixture is still warm, add 20 drops of cold water, drop by drop. This destroys the
excess acetic anhydride.
5. Add 20 mL of water to the flask, then put the flask in an ice bath to cool the mixture and
speed the crystallization of aspirin.
6. When the crystallization seems complete, pour the entire mixture through a Buckner funnel.
7. Apply suction filtration through the funnel and wash the crystals with a few milliliters of
ice cold water.
8. Now time for recrystallization. Transfer the crystals to a beaker and add 10 mL of ethyl alcohol.
Stir to dissolve, warming the beaker to speed the process.
9. When the crystals have dissolved, pour 25 mL of warm water into the alcohol solution. Cover
the beaker and wait until the solution cools and crystals start to re-form. Then place the beaker in an ice bath
to complete the recrystallization.
10. Pour the contents into a Buckner funnel and apply suction filtration.
11. Remove the crystals and place on dry paper to remove excess water.
12. Make sure the melting point is 135°C, just to be sure you made the right stuff.
DO NOT INGEST THIS ASPIRIN. THIS TUTORIAL IS FOR ACADEMIC PURPOSES