Benzoic anhydride is the organic compound with the formula (C6H5CO)2O. It is the acid anhydride of benzoic acid and the simplest symmetrical aromatic acid anhydride. It is a white solid.
Preparation and reactions It is usually prepared by the dehydration reaction of benzoic acid, e.g. using acetic anhydride: 2 C6H5CO2H + (CH3CO)2O → (C6H5CO)2O + 2 CH3CO2H 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: (C6H5CO)2O + ROH → C6H5CO2H + C6H5CO2R
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