- Formed from the removal of water (H2O) from 2 carboxylic acid molecules
- To name, remove ‘acid’ from the parent carboxylic acid name and replace with ‘anhydride’ for the (CO)2O bond system
- e.g. 2 molecules of ethanoic acid ➔ ethanoic anhydride + water
Do you remember the content of A-level Chemistry regarding Acylation of Acyl chloride?
- Acid Anhydride react in a similar way to acyl chlorides with alcohols, phenols, water, ammonia and amines!!
- Less reactive than acyl chlorides
- Useful for some lab preparations where acyl chlorides may be too reactive
Reaction of Acid Anhydrides with Water
Acid anhydride + water ➔ 2 carboxylic acids
e.g. ethanoic anhydride + water ➔ 2 ethanoic acid
Reaction of Acid Anhydrides with Alcohols
Acid anhydride + alcohol ➔ ester + carboxylic acid
e.g. ethanoic anhydride + methanol ➔ methyl ethanoate + ethanoic acid
Reaction of Acid Anhydrides with Ammonia
Acid anhydride + ammonia ➔ primary amide + carboxylic acid
e.g. ethanoic anhydride + NH3 ➔ ethanamide + ethanoic acid
Reactions of Acid Anhydrides with Amines
Acid anhydride + amine ➔ N-substituted amide + carboxylic acid
e.g. ethanoic anhydride + methyl amine ➔ N-methylethanamide + ethanoic acid
Nucleophilic Addition-Elimination Reaction:
This is the end of the topic!
Drafted by Cherry (Chemistry)