Amide from acyl chloride: practice and mechanism
NH₃ replaces the Cl on the carbonyl carbon (addition–elimination) and the C=O stays: acyl chloride → amide.
Example
Acyl chlorides are the most reactive carboxylic acid derivatives. Ammonia attacks, chloride leaves (addition–elimination) and an amide forms; the second NH₃ traps the HCl.
Mechanism step by step
- 1
NH₃ attacks the very electrophilic carbonyl carbon of the acyl chloride.
- 2
In the tetrahedral intermediate C=O re-forms and Cl⁻ is expelled.
- 3
A second NH₃ removes the proton on nitrogen (NH₄Cl forms): amide.
Practice tasks
Which product forms, which reagent is needed? After each answer you see the explanation.
Which main product forms?
Typical mistakes
- The C=O group stays. An amine without C=O would only form by reducing the amide with LiAlH₄.
- A nitrile would only form by removing water from the amide. With NH₃ alone it stays the amide.
Often confused with: Ester from acyl chloride · Acidic hydrolysis of amides and nitriles
Frequently asked questions
Why two equivalents of NH₃?
Otherwise the HCl released would protonate NH₃ to NH₄⁺, which can no longer attack.
Why are amides so stable?
The nitrogen lone pair is conjugated with the C=O group; the C–N bond has partial double-bond character.