Acyl Chloride

Functional group RCOCl (acyl chloride)

CH3COCl ethanoyl chloride

CH3CH2COCl propanoyl chloride

C6H5COCl benzoyl chloride

Preparation of acyl chlorides

An acyl chloride is produced when a carboxylic acid reacts with phosphorus (V) chloride, PCl5 at room temperature.

e.g.

Type of reaction: Nucleophilic Substitution

1. Hydrolysis of acyl chlorides

Acyl chlorides are hydrolysed rapidly with cool water. The reaction is violent and produces a carboxylic acid and hydrogen chloride gas (which is given off as steamy white fumes).

e.g.

Reagent: water

Conditions: room temperature

Name of organic product: carboxylic acid 

Type of reaction: Hydrolysis/Nucleophilic addition-elimination  

2. Reaction of acyl chlorides with alcohols and phenols

Acyl chlorides react with alchohols an phenols at room temperature to form esters. The advantage of preparing esters by this method is that the reaction goes to completion giving a higher yield of ester.

e.g.

Reagent: ethanol (any alcohol or phenol)

Conditions: room temperature

Name of organic product:  alkyl alkanoate

Type of reaction: Nucleophilic addition-elimination

3. Reaction of acyl chlorides with concentrated ammonia

Acyl chlorides with concentrated ammonia at room temperature at room temperature to produce an amide. The nitrogen atom in the ammonia molecule has a lone pair of electrons, which enables the ammonia molecule to act as a nucleophile.

e.g.

Reagents: concentrated ammonia

Conditions: room temperature

Name of organic product: alkanamide

Type of reaction: Nucleophilic addition-elimination

4. Reaction of acyl chlorides with primary amines

Acyl chlorides react with amines at room temperature to form N-substiuted amides.

e.g.    

Reagent: any amine

Conditions: room temperature

Name of organic product: N-alkylalkanamide

Type of reaction: Nucleophilic addition-elimination