Photo by C Lloyd at SSERC (Public Domain)

Aspirin is an analgesic (pain-killing), anti-inflammatory and anti-pyretic (fever-reducing) drug. It is an ester and can be prepared by the condensation reaction between 2-hydroxybenzoic acid (or salicylic acid) and ethanoic anhydride:

After purification by recrystallisation, the product can be weighed and the percentage yield determined. The purity of the final sample can be checked by determining its melting point.

Preparation of aspirin – pupil guide

Preparation of aspirin – Teacher’s guide

Preparation of aspirin – Risk assessment