Method for preparing 2-bromo anthraquinone

The invention discloses a method for preparing 2-bromo anthraquinone, comprising that bromobenzene and phthalic anhydride are reacted for 2-3 hours by being mixed at 40-50 DEG C with existence of anhydrous aluminum chloride,, thereby obtaining 2-(4-bromobenzeneacyl) phenylformic acid, wherein, quantity ratio of phthalic anhydride to bromobenzene to anhydrous aluminum chloride is 5:29:12. The 2-(4-bromobenzeneacyl) phenylformic acid is purified and then dissolved in concentrated sulfuric acid and temperature is raised gradually to 170 DEG C while mixing; and 2-bromo anthraquinone crude product is obtained by reaction. The 2-bromo anthraquinone crude product is cooled to 20-25 DEG C and then mixed with crushed ice; the mixture is stirred, filtered and washed. Toluol is used as solvent to carry out purification and active carbon is then used to carry out decoloring, then filtering and crystallizing are carried out, thereby obtaining 2-bromo anthraquinone. The invention can prepare 2-bromo anthraquinone in a rela