Online Encyclopedia

ANTHRACENE (from the Greek avOpa, coal)

Online Encyclopedia
Originally appearing in Volume V02, Page 105 of the 1911 Encyclopedia Britannica.
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ANTHRACENE (from the Greek avOpa, coal), Cr4H1o, a hydrocarbon obtained from the fraction of the coal-tar distillate boiling between 270° and 400° C. This high boiling fraction is allowed to stand for some days, when it partially solidifies. It is then separated in a centrifugal machine, the low melting-point impurities are removed by means of hot water, and the residue is finally hot-pressed. The crude anthracene cake is purified by treatment with the higher pyridine bases, the operation being carried out in large steam-jacketed boilers. The whole mass dissolves on heating, and the anthracene crystallizes out on cooling. The crystallized anthracene is then removed by a centrifugal separator and the process of solution in the pyridine bases is repeated. Finally the anthracene is purified by sublimation. Many synthetical processes for the preparation of anthracene and its derivatives are known. It is formed by the condensation of acetylene tetrabromide with benzene in the presence of aluminium chloride: Br•CH•Br C6H6+ I +C6H6=4HBr+C6H4K. I 4H4, Br•CH•Br and similarly from methylene dibromide and benzene, and also when benzyl chloride is heated with aluminium chloride to 200° C. By condensing ortho-brombenzyl bromide with sodium, C. L. Jackson and J. F. White (Ber., 1879, 12, p. 1965) obtained dihydro-anthracene
End of Article: ANTHRACENE (from the Greek avOpa, coal)
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