Acylation (A2 Only)
Chemistry: AQA A Level, topic 6.3.2
Acylation
Acylation reactions can be used to produce a variety of organic compounds, like amides.
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Compounds
- The above compounds are examples of acylated materials.
Nucleophilic addition-elimination
- The nucleophilic addition-elimination reaction happens with acyl chlorides and acid anhydrides.
- It is used to produce amides, carboxylic acids, and esters.
- The mechanism is on the next slide.
Mechanism
- This reaction can also be done with water or ammonia as nucleophile.
Industrial Use of Acylated Molecules
Acylated molecules have many uses in industry.
Dangers
- Ethanoyl chloride is a dangerous material.
- If it gets wet, it will produce HCl gas which burns skin.
- This is really painful.
Solutions
- In industry, and more generally in labs, we would use ethanoic anhydride.
- Ethanoic anhydride is slightly less reactive but is much safer.
- It’s more stable, so can be stored easily.
- It’s cheaper because we don't need to use other compounds to make it (making acid chlorides uses sulfur or phosphorous compounds).
Aspirin
- Aspirin is an example of an ester made with ethanoic anhydride.
- The final step in the synthesis is an esterification reaction. This is depicted above.
Test yourself on Acylation (A2 Only)
In the mechanism of acyl chloride to an ester, what is removed?
Why is ethanoic anhydride better in industry than ethanoyl chloride?
What's the final step of aspirin synthesis?