安息香酸無水物

解説安息香酸無水物，結晶．融点42 ℃，沸点360 ℃．d1541.99．n15D1.5766．エタノール，エーテルなどに可溶．無水酢酸よりも反応性は劣るが，ヒドロキシ基やアミノ基のベンゾイル化剤として用いられる．森北出版「化学辞典（第2版）

使用Benzoic 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.

一般的な説明Benzoic anhydride undergoes Friedel-Crafts acylation reaction with benzene over various ion-exchanged heteropoly acids to yield benzophenone.

製造方法To 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).

純化方法Free it from benzoic acid by washing with NaHCO3, then water, and drying. Crystallise it from *benzene (0.5mL/g) by adding just enough pet ether (b 40-60o) to cause cloudiness, then cool in ice. It can be distilled at 210-220o/20mm. [Beilstein 19 IV 550.]