Anhydride hydrolysis
Water attacks an anhydride carbonyl, and collapse of the tetrahedral intermediate breaks the acyl-oxygen linkage. Proton transfer gives carboxylic-acid products; a mixed anhydride yields two different acids.
- Reagents
- H2O
- Conditions
- Aqueous hydrolysis
- Reaction class
- Anhydride hydrolysis
- Equation
- (RCO)2O + H2O -> 2RCOOH
Overview
Water attacks an anhydride carbonyl, and collapse of the tetrahedral intermediate breaks the acyl-oxygen linkage. Proton transfer gives carboxylic-acid products; a mixed anhydride yields two different acids.
Transformation
Acid anhydrides → Carboxylic acids
- Equation
- (RCO)2O + H2O -> 2RCOOH
- Reagents
- H2O
- Environment
- Aqueous hydrolysis
- Reaction class
- Anhydride hydrolysis
- Mechanism
- nucleophilic acyl substitution
- Evidence level
- textbook core
Scope and limitations
- Scope
- Equation represents a symmetrical anhydride.
- Limitations
- Mixed anhydrides give two different acids; cyclic anhydrides give a dicarboxylic acid.
Related reactions
- Oxidation: Alcohols → Carboxylic acids
Full oxidation of a primary alcohol gives a carboxylic acid.
- Complete oxidation: Primary alcohols → Carboxylic acids
Full oxidation of a primary alcohol gives a carboxylic acid.
- Reduction: Carboxylic acids → Primary alcohols
Reduction of a carboxylic acid gives a primary alcohol.
- Oxidation: Aldehydes → Carboxylic acids
Oxidation of an aldehyde gives a carboxylic acid.
- Hydrolysis: Nitriles → Carboxylic acids
Nitriles can be hydrolysed to carboxylic acids, splitting the old aggregate nitrile-to-amide route into a single functional-group conversion.
- Activation for amide formation: Carboxylic acids → Amide chemistry
Carboxylic acids or activated acid derivatives connect to amide-bond formation.
- Esterification: Carboxylic acids → Esters
Carboxylic acids react with alcohols to form esters.
- Hydrolysis: Esters → Carboxylic acids
Hydrolysis converts esters back into carboxylic acid products.
- 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.
- Carboxylation: Grignard reagents → Carboxylic acids
Grignard carboxylation gives carboxylic acids after acidic work-up.
- Grignard carboxylation co reactant: Carbon dioxide → Carboxylic acids
Carbon dioxide plus a Grignard reagent gives a carboxylic acid after acidic work-up.
- Salt formation: Carboxylic acids → Carboxylate salts
Carboxylic acids react with bases, carbonates and reactive metals to form carboxylate salts.
- Anhydride alcoholysis: Acid anhydrides → Esters
Alcohol oxygen attacks an anhydride carbonyl and the tetrahedral intermediate expels carboxylate. Proton transfer produces the ester and a carboxylic acid; one acyl fragment transfers to the alcohol.
- Anhydride ammonolysis: Acid anhydrides → Amides
Ammonia attacks the anhydride carbonyl to form a tetrahedral intermediate. Carboxylate departure and proton transfer give an amide; excess ammonia also converts the acid co-product into ammonium carboxylate.
References
- Organic Chemistry: Chemistry of Acid AnhydridesJohn McMurry · OpenStax Organic Chemistry · 2023
Supports functional-group chemistry used to curate the linked examples. Checked 2026-09-16; named examples are applications of textbook scope, without claimed experimental yields.