The Friedel-Crafts Reaction Anthraquinone and Anthracene

Prelab Exercise Draw the mechanism for the cyclization of 2-benzoylbenzoic acid to anthraquinone using concentrated sulfuric acid. [Pg.457]

The Friedel-Crafts reaction of phthalic anhydride with excess benzene as solvent and two equivalents of aluminum chloride proceeds rapidly and gives a complex salt of 2-benzoylbenzoic acid in which one mole of aluminum chloride has reacted with the acid function to form the salt RCOj AlClj and a second mole is bound to the carbonyl group. On addition of ice and hydrochloric acid the complex is decomposed and basic aluminum salts are brought into solution. [Pg.457]

Treatment of 2-benzoylbenzoic acid with concentrated sulfuric acid effects cyclodehydration to anthraquinone, a pale-yellow, high-melting compound of great stability. Because anthraquinone can be sulfonated only under forcing conditions, a high temperature can be used to shorten the reaction time without loss in yield of product the conditions are so adjusted that anthraquinone separates from the hot solution in crystalline form favoring rapid drying. [Pg.457]

Reduction of anthraquinone to anthrone can be accomplished rapidly on a small scale with tin(II) chloride in acetic acid solution. A second [Pg.457]

Reduction of anthrone to anthracene is accomplished by refluxing in aqueous sodium hydroxide solution with activated zinc dust. The method has the merit of affording pure, beautifully fluorescent anthracene. [Pg.458]

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