What Is the Reaction Between Acetic Anhydride and Water?

The reaction between acetic anhydride and water is written as follows: (CH3CO)2O + H2O –> 2CH3COOH. This reaction produces two molecules of etanoic acid, a compound that appears as a colorless liquid. Acetic anhydride is highly reactive to water, and this reaction becomes especially dangerous when mineral acids, such as nitric or sulphuric acid, are present. Acetic anhydride also produces violent reactions when mixed with boric acid, ethanol and methanol.

Acetic anhydride, also called acetyl ether or ethanoic anhydride, is a compound with the chemical formula C4H6O3 and a molecular weight value of 102.08. It appears as a clear, colorless liquid that has a pungent vinegar odor. Apart from being highly reactive to water, acetic anhydride is also flammable, generating dangerous vapours when heated.

As a volatile compound, acetic anhydride does not cause severe skin irritation, unless it gets in contact with wet clothes. Prolonged exposure to this chemical increases the risk of skin and eye burns, irritation of the respiratory tract, nausea and vomiting.

While working with acetic anhydride, it is recommended to wear protective clothing and eye protection to reduce the risk of lesions. If the skin or clothes come in contact with this compound, the worker must remove all contaminated clothes and wash the skin with water. Acetic anhydride is soluble in cold water, but easily decomposes in hot water.