Acetic anhydride

Ethanoic anhydride, an acylating reagent with two linked acetyl groups.

Formula
C4H6O3
Molar mass
102.09 g/mol
Also known as
acetyl acetate, Acetanhydride, Ethanoic anhydride, Acetyl oxide, Acetyl anhydride, Acetic oxide

Overview

Ethanoic anhydride, an acylating reagent with two linked acetyl groups.

An oxygen atom joins two acyl groups. Reaction with an alcohol forms an ester and a carboxylic-acid coproduct; reaction with an amine can form an amide. It is more reactive toward these nucleophiles than a simple ester, but reaction conditions still control selectivity.

Identifiers

Formula
C4H6O3
Molar mass
102.09 g/mol
Also known as
acetyl acetate, Acetanhydride, Ethanoic anhydride, Acetyl oxide, Acetyl anhydride, Acetic oxide
Chemical identifiers
SMILES
CC(=O)OC(=O)C
InChI
InChI=1S/C4H6O3/c1-3(5)7-4(2)6/h1-2H3
PubChem CID
7918

Properties

Melting Point
-73.4 °C
Boiling Point
139.5 °C
Density
1.082 g/cu cm at 20 °C
Water solubility
In water, 120 g/L at 20 °C

Related compounds

  • Acid anhydrides

    Acetic anhydride is a specific member of the acid anhydrides family.

References

  1. PubChem Compound Summary: Acetic anhydride (CID 7918)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

  2. OpenStax Organic Chemistry: Chemistry of acid anhydridesJohn McMurry · OpenStax · 2023

    Supports the qualitative structural interpretation of the recorded molecular structure; no new physical measurement or verified preparative yield is claimed.

  3. Hazardous Substances Data Bank (HSDB): Acetic anhydride — melting pointHazardous Substances Data Bank (HSDB)

    Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/7918#section=Melting-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-4

  4. Hazardous Substances Data Bank (HSDB): Acetic anhydride — boiling pointHazardous Substances Data Bank (HSDB)

    Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/7918#section=Boiling-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-4

  5. Hazardous Substances Data Bank (HSDB): Acetic anhydride — densityHazardous Substances Data Bank (HSDB)

    Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/7918#section=Density. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-4

  6. Hazardous Substances Data Bank (HSDB): Acetic anhydride — solubilityHazardous Substances Data Bank (HSDB)

    Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/7918#section=Solubility. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 96