Producing Amides (Cambridge (CIE) A Level Chemistry): Revision Note

Production of Amides

• Amides are organic compounds with an -CONR₂ functional group

• They can be prepared from the condensation reaction between an acyl chloride and ammonia or amine

• In a condensation reaction, two organic molecules join together and in the process eliminate a small molecule

• In this case, the acyl chlorides and ammonia or amine join together to form an amide and eliminate an HCl molecule

Condensation reaction

• The chlorine atom in acyl chlorides is electronegative and draws electron density from the carbonyl carbon

• The carbonyl carbon is therefore electron-deficient and can be attacked by nucleophiles

• The nitrogen atom in ammonia and amines has a lone pair of electrons which can act as a nucleophile and attack the carbonyl carbon

• As a result, the C-Cl bond is broken and an amide is formed

• Whether the product is a substituted amide or not, depends on the nature of the nucleophile

  • Primary and secondary amines will give a substituted amide

  • The reaction of acyl chlorides with ammonia will produce a non-substituted amide

• Note that amides can also be formed from the condensation reaction between carboxylic acids and ammonia or amines

• However, this reaction is slower as carboxylic acids are less reactive than acyl chlorides and the reaction doesn’t go to completion

Condensation reactions of propanoyl chloride to form different substituted amides

Acyl chlorides undergo condensation reactions with ammonia to form amides and with amines to form substituted amides