Manufacture of Aspirin (AQA A Level Chemistry): Revision Note

Manufacture of Aspirin

Manufacture of Aspirin

• Acylation reactions have many uses, such as in the pharmaceutical and textile industries for making drugs, e.g. aspirin, and textiles, e.g. cellulose acetate

• In the industrial manufacture of aspirin, salicylic acid and ethanoic anhydride are reacted together in an acylation reaction to form aspirin and ethanoic acid

     Salicylic acid            Ethanoic anhydride                    Aspirin                               Ethanoic acid

Equation showing the manufacture of aspirin

• The reaction of acyl chlorides with water or alcohols produces carboxylic acid and esters respectively

  • However it is normally a fast, exothermic process with a rapid production of highly corrosive hydrogen chloride gas

• In general, acid anhydrides are preferred over acyl chlorides in the production of aspirin because they are also cheaper to produce, less reactive and the reactions can be more easily controlled

• For acid anhydrides, the by-product is the less corrosive carboxylic acid compared to hydrogen chloride for acyl chlorides