Acetic anhydride

Acetic anhydride (CAS 108-24-7), also known as AC2O, acetyl oxide, acetic oxide, and acetyl ether, is a reactive organic compound formed by the dehydration of acetic acid. It functions as an acetylating agent, transferring acetyl groups to hydroxyl or amine groups in target molecules.

In pharmaceutical manufacturing, acetic anhydride acetylates salicylic acid to produce aspirin and serves as a key reagent in synthesising cellulose acetate for controlled-release drug coatings. In textile processing, it acetylates cellulose fibres to improve dimensional stability and resistance to moisture. It also initiates polymerisation reactions in the production of vinyl acetate-based polymers.

Acetic anhydride is supplied in technical and pharmaceutical grades and is subject to REACH registration requirements across the EU. As a drug precursor, it is classified under EU Regulation 273/2004 and requires documented end-use declarations. It is typically available in drums and isotanks.