The Synthesis Of Aspirin

For centuries, the use of the extracts from various medicinal plants have been used for the treatment of pain and fever. One among those plants, called white willow (Salix alba), contained the derivatives of salicylic acid is famous to have the properties of relief for pain and fever. By the year 1760’s, one of the active ingredients of these plants, that is, salicin was discovered. Salicin, salicylic acid and aspirin belong to a family of medicinally useful compounds called salicylates.

The hydroxyl group present on the salicylic acid is corrosive. As a result, salicylic acid cannot be easily ingested. This property is present in many other compounds that have free phenolic groups. Therefore, an acetyl group, is added to salicylic acid to create acetylsalicylic acid (ASA). So

The crystals were then kept aside for further investigations.

Step 2- Synthesis of Aspirin A warm water was prepared by heating approximately 100mL of distilled water in a 400mL beaker along with few boiling chips to 45-50 ℃. 3.0g of salicylic acid was weighed (salicylic acid was formed from Step 1) into a 100mL beaker. In a 10mL graduated cylinder, 5.0mL of acetic anhydride was measured and was transferred into the 100mL beaker. 5 drops of concentrated sulphuric acid was also added into the beaker. The mixture was heated gently in the water bath and was stirred continuously until all the solid had dissolved. An oil layer had also formed while the mixture was being warmed but it had dissolved with continued heating. After being warmed for another 5-10 minutes, the reaction vessel was removed from the water bath. The reaction mixture was then cooled down to room temperature and was not disturbed during the cooling process. Crystals were formed and then the beaker was placed into an ice-water bath until the liquid had thickened into a semi-solid