Acetic anhydride

Description

Acetic anhydride (chemical formula: (CH3CO)2O) is the simplest isolable anhydride of a carboxylic acid, is widely used as a reagent in organic synthesis. It has an internal asymmetric structure, leading to its potent electrophilicity. In organic chemistry, it is mainly used in acetylation for the manufacture of commercially significant materials, e.g. it can be used for the conversion of cellulose to cellulose acetate and aspirin. It can also be used as a wood preservative. In starch industry, it is a common acetylation compound for acetylation of monoglyceride. It is also an esterification agent for the production of modified starches. It is produced by carbonylation of methyl acetate or the reaction between ketene and acetic acid.

Description

Acetic anhydride (Ac2O) is a liquid with a strong acetic acid smell (acetic acid is liberated during the hydrolysis of acetic anhydride by moisture in the air). Acetic anhydride is typically used for acetylation of alcohols or amines.

The Uses of Acetic anhydride

Acetic anhydride is used chiefly as an acetylating and dehydrating agent; it is used on a large scale for the acetylation of cellulose. Other areas of application for acetic anhydride are:
1) The production of poly(methylacrylimide) hard foam, where acetic anhydride is used for binding the ammonia that is liberated on conversion of two amide groups to an imide group.
2) Acetylated plastic auxiliaries, such as glycerol triacetate, acetyl tributyl citrate, and acetyl ricinolate.
3) Preparation of anhydrous acetic acid in nonaqueous titrimetry.