Acyl chlorides
Acyl chlorides connect carboxylic acid chemistry to esters, amides and N-substituted amides through acylation.
- Functional group
- COCl
- Also known as
- acid chloride, acyl chloride
Overview
Reactive carboxylic acid derivatives containing C(O)-Cl.
Acyl chlorides connect carboxylic acid chemistry to esters, amides and N-substituted amides through acylation.
Acyl chlorides contain R-C(=O)-Cl. The electrophilic carbonyl carbon is attacked by water, alcohols or nitrogen nucleophiles, followed by chloride departure. Their readiness to hydrolyse explains why dry conditions matter when water is not the intended reactant.
Identifiers
- Functional group
- COCl
- Also known as
- acid chloride, acyl chloride
Chemical identifiers
- SMILES
- CC(=O)Cl
Properties
- Acyl chloride or haloalkane
- Acyl substitution at C=O is distinct from substitution at a saturated carbon in R-CH2-Cl.
- Acid by-product
- HCl must be accounted for; ammonia or an amine can supply both nucleophile and acid-neutralising base.
Related compounds
- Acetyl chloride
Ethanoyl chloride, a reactive carboxylic-acid derivative.
- Benzoyl chloride
An aromatic acyl chloride connecting benzoic-acid derivatives.
Connected reactions
- Chlorination: Carboxylic acids → Acyl chlorides
PCl5 converts carboxylic acids into acyl chlorides.
- Chlorination with thionyl chloride: Carboxylic acids → Acyl chlorides
Thionyl chloride converts carboxylic acids into acyl chlorides with sulfur dioxide and hydrogen chloride as by-products.
- Hydrolysis: Acyl chlorides → Carboxylic acids
Water hydrolyses acyl chlorides to carboxylic acids, releasing hydrogen chloride.
- Acylation: Acyl chlorides → Esters
Alcohol acylation converts acyl chlorides into esters.
- Acylation: Acyl chlorides → Amides
Ammonia acylation converts acyl chlorides into amides.
- Acylation: Acyl chlorides → N-substituted amides
Amine acylation converts acyl chlorides into N-substituted amides.
References
- Organic Chemistry: Chemistry of Acid HalidesJohn McMurry · OpenStax Organic Chemistry · 2023
Supports acid-halide preparation with thionyl chloride and nucleophilic acyl substitution chemistry, including tetrahedral intermediates, hydrolysis, alcoholysis and amine acylation at acid chlorides.
- PubChem Compound Summary: Acetyl chloride (CID 6367)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Benzoyl chloride (CID 7412)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.