Benzoic anhydride is the organic compound with the formula (C<sub>6</sub>H<sub>5</sub>CO)<sub>2</sub>O. It is the acid anhydride of benzoic acid and the simplest symmetrical aromatic acid anhydride. It is a white solid.
It is usually prepared by the dehydration reaction of benzoic acid, e.g. using acetic anhydride:
Alternatively, sodium benzoate can be treated with benzoyl chloride. It can be produced by dehydrating benzoic acid by heating.
Benzoic anhydride provides a convenient way to prepare benzoic esters: