| 摘要 |
Anthracene is purified by selectively dissolving impurities such as carbazole and phenanthrene in a dialkyl sulphoxide or a dialkyl formamide; the carbazole and phenanthrene may be recovered from the mother liquors. The crude anthracene may be heated with the solvent at 80-120 DEG C., cooled and filtered at 20-80 DEG C.; several steps may be used, if desired the solvent and anthracene proceeding in countercurrent directions so that at each stage anthracene is treated with filtrate from the succeeding stage, using pure solvent in the final stage. In the final stage the filtration may be carried out at a higher temperature and the dissolved anthracene crystallized from the filtrate and supplied to an earlier stage. At any stage the anthracene may be washed with pure solvent or another solvent. Tarry impurities may be removed beforehand by treatment with benzene or toluene. The anthracene may be recrystallized from the sulphoxide or formamide, bleaching earth or active carbon being added to the solution. The anthracene may be finally purified by sublimation. Carbazole and phenanthrene may be recovered from the mother liquors by distilling off the solvent or by precipitation by adding a liquid in which they are insoluble, e.g. water, preferably after concentration of the mother liquors.
|
