Benzoic anhydride is the

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

with the formula (C₆H₅CO)₂O. It is the

acid anhydride An acid anhydride is a type of chemical compound derived by the removal of water molecules from an acid. In organic chemistry, organic acid anhydrides contain the functional group . Organic acid anhydrides often form when one equivalent of wa ...

benzoic acid Benzoic acid () is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. The benzoyl group is often abbreviated "Bz" (not to be confused with "Bn," which ...

and the simplest symmetrical aromatic acid anhydride. It is a white solid.

Preparation and reactions

It is usually prepared by the

dehydration reaction In chemistry, a dehydration reaction is a chemical reaction that involves the loss of an H2O from the reacting molecule(s) or ion(s). This reaction results in the release of the H2O as water. When the reaction involves the coupling of two molecu ...

of benzoic acid, e.g. using

acetic anhydride Acetic anhydride, or ethanoic anhydride, is the chemical compound with the chemical formula, formula . Commonly abbreviated , it is one the simplest organic acid anhydride, anhydrides of a carboxylic acid and is widely used in the production of c ...

: :2 C₆H₅CO₂H + (CH₃CO)₂O → (C₆H₅CO)₂O + 2 CH₃CO₂H Alternatively,

sodium benzoate Sodium benzoate also known as benzoate of soda is the sodium salt of benzoic acid, widely used as a food preservative (with an E number of E211) and a pickling agent. It appears as a white crystalline chemical with the formula C6H5COONa. Pro ...

can be treated with

benzoyl chloride Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula . It is a colourless, fuming liquid with an irritating odour, and consists of a benzene ring () with an acyl chloride () substituent. It is ...

. It can be produced by dehydrating benzoic acid by heating. Benzoic anhydride provides a convenient way to prepare benzoic esters: :(C₆H₅CO)₂O + ROH → C₆H₅CO₂H + C₆H₅CO₂R

References

{{Reflist Carboxylic anhydrides