Form an amide by condensation of ammonia or an amine with an acyl chloride
At room temperature, ammonia or an amine reacts with an acyl chloride to form an amide and HCl.
Section 34 · Nitrogen compounds
A Level; Cambridge International Chemistry 9701, 2028–2030 syllabus, Topic 34. Use the stated reagents, conditions and product scope. Written practice is self-checked This online lesson cannot demonstrate supervised laboratory skills.
Before you begin
- Recall nucleophilic substitution, reduction, acyl-chloride addition–elimination, acid–base equilibria and covalent bonding.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which product class forms when ammonia reacts with an acyl chloride?
What you will learn
- Describe amide formation from an acyl chloride
- Distinguish ammonia from amine-derived nitrogen substitution
- Identify HCl as the other product
Join nitrogen to the acyl carbon
Ammonia or an amine reacts with an acyl chloride at room temperature. Nitrogen attacks the acyl carbon and replaces chlorine; the product is an amide plus HCl.
Ammonia gives a primary amide, RCONH₂. A primary amine can give an N-substituted amide, RCONHR′. Excess ammonia or amine can accept HCl, forming an ammonium salt in a fully balanced equation.
This is condensation at the acyl group
The reaction combines an acyl fragment and an N-containing reagent while eliminating HCl overall.
This outcome overlaps the amide preparation section later in Topic 34. Keep the amide carbonyl in the product and preserve any carbon group already attached to the amine nitrogen.
Pause and explain
What is the organic product from an acyl chloride and a primary amine?
Worked example
Predict the product from ethanoyl chloride and methylamine.
Show the worked solution
- Keep the ethanoyl carbonyl.
- Replace Cl with NHCH₃.
- Include HCl as the by-product.
Answer N-methylethanamide, CH₃CONHCH₃, and HCl.
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Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Complete CH₃COCl + NH₃ → … at the organic-product level.
Give me a hint
Replace chlorine with NH₂ and include hydrogen chloride.
Compare my reasoning
- Retain CH₃CO–.
- Form CH₃CONH₂.
- Write HCl as the other product.
CH₃CONH₂ + HCl (ethanamide and hydrogen chloride).
Look for these in your work
- Carbonyl retained
- Amide formed
- HCl included
Predict the amide from propanoyl chloride and ethylamine.
Give me a hint
Keep the ethyl group on nitrogen.
Compare my reasoning
- The acyl fragment is CH₃CH₂CO–.
- Replace Cl with NHCH₂CH₃.
- Name the product as N-ethylpropanamide.
N-ethylpropanamide, CH₃CH₂CONHCH₂CH₃, plus HCl.
Look for these in your work
- Acyl chain
- N-ethyl group
- Amide class
A student draws CH₃COOCH₃ from ethanoyl chloride and methylamine. Identify the functional-group mismatch.
Give me a hint
Look for the atom linking the acyl carbon to the incoming reagent.
Compare my reasoning
- Methylamine supplies nitrogen, not oxygen.
- The product must contain an amide C–N bond.
- The product is an N-methyl amide.
The product is N-methylethanamide, CH₃CONHCH₃; an ester would require an alcohol or phenol oxygen nucleophile.
Look for these in your work
- Nucleophile identified
- Amide linkage
- Ester distinguished
Common mistakes
- Replacing the carbonyl oxygen with nitrogen
- Removing the amine's methyl group
- Writing an ester
- Omitting HCl
What can you explain now?
Which product class forms when ammonia reacts with an acyl chloride?
Compare with the explanation
An amide
Nitrogen replaces the chlorine at the acyl carbon.
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Make it stick
How do ammonia and amines differ in the amide products they form from acyl chlorides?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.