Innovating Science® Properties of Aspirin

What is Aspirin made of?

In a reaction vessel salicylic acid, acetic anhydride and sulfuric acid are mixed. The exothermic reaction will cause the temperature to increase to 70 to 80 °C. Once the reaction is complete the vessel is cooled in an ice bath and the acetylsalicylic acid crystallizes out. This material is re-crystallized in toluene to purify the product. The product identity is confirmed by melting point. The mass of the re-crystallized product is used to determine the yield of the synthesis. In this experiment, we will perform the synthesis of acetylsalicylic acid (aspirin), purification by re-crystallization and use melting point to confirm identity.