# Aspirin (2-ethanoylhydroxybenzoic acid) is manufactured by reacting 2-hydroxybenzoic acid with ethanoic anhydride rather than with ethanoic acid. Explain why ethanoic anhydride is preferred over ethanoic acid for this esterification reaction, and state the name of the other organic product formed when ethanoic anhydride reacts with the hydroxyl group of 2-hydroxybenzoic acid.

> Edexcel A-Level Chemistry (9CH0) — 17.3 Carboxylic acids and derivatives · Explain · 5 marks

> Aspirin is one of the world's most widely used medicines. Its synthesis involves an acylation reaction in which an —OH group reacts with an acylating agent to form an ester linkage.

## Mark scheme (5 marks)

1. Ethanoic anhydride is a more reactive acylating agent than ethanoic acid
2. Ethanoic acid is a poor acylating agent because the —OH group on the carboxyl group makes it less electrophilic / the carbonyl carbon is less susceptible to nucleophilic attack
3. The reaction of ethanoic acid with an alcohol is reversible / an equilibrium, whereas the reaction of ethanoic anhydride is essentially irreversible
4. Ethanoic anhydride is safer / less hazardous to handle than acyl chlorides (e.g. ethanoyl chloride), which also makes it preferable on an industrial scale
5. The other organic product is ethanoic acid

## Key terms

- [ethanoic anhydride](https://www.gradenine.co.uk/glossary/ethanoic-anhydride)
- [esterification](https://www.gradenine.co.uk/glossary/esterification)

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- [Revision notes for Edexcel A-Level Chemistry (9CH0)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/aspirin-2-ethanoylhydroxybenzoic-acid-is-manufactured-by-09d36be5) · Published by Druglandscape Ltd.