Anhydride alcoholysis

Overview

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.

Transformation

Acid anhydrides → Esters

Equation

(RCO)2O + R′OH -> RCOOR′ + RCOOH

Reagents

Alcohol R′OH

Environment

Acylation; catalyst depends on substrate

Reaction class

Anhydride alcoholysis

Mechanism

nucleophilic addition-elimination

Evidence level

textbook core

Scope and limitations

Scope

One acyl group transfers to the alcohol oxygen.

Limitations

Anhydride acylation is distinct from reversible acid/alcohol esterification.

Related reactions

• Esterification: Carboxylic acids → Esters

  Carboxylic acids react with alcohols to form esters.

• Esterification co reactant: Alcohols → Esters

  Alcohols combine with carboxylic acids to form esters.

• Hydrolysis: Esters → Carboxylic acids

  Hydrolysis converts esters back into carboxylic acid products.

• Hydrolysis co product: Esters → Alcohols

  Hydrolysis of an ester also regenerates the alcohol component.

• Acylation: Acyl chlorides → Esters

  Alcohol acylation converts acyl chlorides into esters.

• Anhydride hydrolysis: Acid anhydrides → Carboxylic acids

  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.

• 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

1. A-level Chemistry 7405: Organic chemistryAQA · AQA specification

   Checked 2026-09-16. Supports A-level topic coverage, including acid anhydrides, acylation and aspirin, amines, amino acids, polymers, synthesis and analysis. Coverage varies by examination board.