Reactions of Acyl Chlorides with Water, Alcohols, Ammonia and Amines

Acyl chlorides react rapidly at room temperature with nucleophiles that have a lone pair on an oxygen or nitrogen atom. In every case HCl is eliminated.1. Water gives a carboxylic acid. The reaction is vigorous and gives steamy fumes of HCl.
CH₃COCl + H₂O → CH₃COOH + HCl
2. Alcohols give an ester.
CH₃COCl + CH₃OH → CH₃COOCH₃ + HClThe product is methyl ethanoate. Unlike esterification with a carboxylic acid, this reaction is not reversible, is fast at room temperature and needs no catalyst, so the yield is higher.3. Ammonia (concentrated) gives a primary amide. The HCl formed reacts with a second ammonia molecule, so it appears as ammonium chloride:
CH₃COCl + 2NH₃ → CH₃CONH₂ + NH₄ClThe product is ethanamide.4. Primary amines give an N-substituted amide. Again the HCl reacts with a second amine molecule:
CH₃COCl + 2CH₃NH₂ → CH₃CONHCH₃ + CH₃NH₃⁺Cl⁻The product is N-methylethanamide.All four are addition-elimination reactions: the lone pair of the nucleophile attacks the δ+ carbonyl carbon, then Cl⁻ and H⁺ are lost as HCl.Worked example: predict the product of propanoyl chloride and ethanol. The ethoxy group from ethanol replaces Cl:
CH₃CH₂COCl + CH₃CH₂OH → CH₃CH₂COOCH₂CH₃ + HClThe ester is ethyl propanoate.