Benzoic anhydride

UsesBenzoic anhydride is used as a benzoylating agent in the manufacture of pharmaceuticals, dyes and intermediates. It serves as an arylation agent in the Heck reaction. It is also used to get benzoic acid through dehydration. Further, it is used to prepare furan-2-yl-phenyl-methanone, which is similar to Friedel-Crafts acylation reaction. In addition to this, it is used for the synthesis of carboxylic esters and lactones.

UsesBenzoic Anhydride is the more active analogue of benzoic acid formed via dehydration. Benzoic Anhydride is used in the synthesis of a wide range of organic compounds including some dyes. Benzoic Anhyd ride is also used as an arylation agent in the Heck reaction.

UsesIn organic syntheses, as benzoylating agent in the manufacture of pharmaceuticals, dyes, and intermediates.

General DescriptionBenzoic anhydride undergoes Friedel-Crafts acylation reaction with benzene over various ion-exchanged heteropoly acids to yield benzophenone.

PreparationTo a flask containing 14.0 gm (0.1 mole) of benzoyl chloride and equipped with a stirrer is added 40 ml of dry dioxane and it is cooled to 5°C.Then 10 ml (0.1 mole) of dry pyridine is rapidly added at 5-10°C followed by 1.0 ml (0.056 mole) of water. After stirring for 10-15 min at 0-5°C, the reaction mixture is then poured into a mixture of 75 ml of cone, hydrochloric acid, 75 gm of cracked ice, and 350 ml of water. The product is filtered, washed first for 1 min with a cold 5% solution of sodium bicarbonate and then with water. The product is dried to afford 11.0 gm (97%), m.p. 43°C (recrystallized from a mixture of ether-petroleum ether).