# Ethanoyl chloride and ethanoic anhydride are both acylating agents that can react with ethanol to form an ester. Explain why ethanoyl chloride is described as the more vigorous acylating agent, and describe one advantage of using ethanoic anhydride over ethanoyl chloride in industrial ester synthesis.

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

> Acylating agents are widely used in the chemical industry to introduce acyl groups into organic molecules. Ethanoyl chloride reacts violently with ethanol at room temperature, producing misty fumes of hydrogen chloride gas. Ethanoic anhydride reacts more slowly with ethanol but still produces the same ester product.

## Mark scheme (5 marks)

1. Ethanoyl chloride reacts faster / more readily with ethanol than ethanoic anhydride
2. The C–Cl bond is more polar / more easily broken than the C–O bond in ethanoic anhydride, making ethanoyl chloride a more effective acylating agent
3. Ethanoyl chloride produces HCl (hydrogen chloride) as a by-product, which is corrosive / toxic / hazardous
4. Ethanoic anhydride does not produce HCl / produces ethanoic acid as a by-product, which is less hazardous
5. Ethanoic anhydride is cheaper / more economical / easier to store and handle safely at industrial scale

## Key terms

- [acylating agent](https://www.gradenine.co.uk/glossary/acylating-agent)
- [ethanoyl chloride](https://www.gradenine.co.uk/glossary/ethanoyl-chloride)
- [ethanoic anhydride](https://www.gradenine.co.uk/glossary/ethanoic-anhydride)

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/ethanoyl-chloride-and-ethanoic-anhydride-are-cde39e18) · Published by Druglandscape Ltd.