Alcohols with acyl chlorides
Alcohols with acyl chlorides
- At A Level, an alcohol gains one more reaction.
- It reacts with an acyl chloride to make an ester.
- This works faster and more completely than using a carboxylic acid.
Practice
An alcohol reacting with an acyl chloride gives:
The alcohol's –OH reacts with the acyl chloride to form an ester, releasing HCl.
The reaction
- An alcohol + an acyl chloride → an ester (plus fumes of $\text{HCl}$).
- It is faster and more complete than esterification with a carboxylic acid.
- E.g. ethanol + ethanoyl chloride → ethyl ethanoate + HCl.
Practice
Compared with using a carboxylic acid, making an ester from an acyl chloride is:
Acyl chlorides are very reactive, so esterification with them is fast and goes essentially to completion.
Practice
Ethanol + ethanoyl chloride gives:
The ester ethyl ethanoate forms, along with HCl fumes.
You've got it
Key idea
- an alcohol + acyl chloride → ester (+ HCl)
- this is faster and more complete than using a carboxylic acid
- e.g. ethanol + ethanoyl chloride → ethyl ethanoate