PHENANTHRENE, Ci 4 H 10 , a hydrocarbon isomeric with anthracene, with which it occurs in the fraction of the coal tar distillate boiling between 27o-4oo C. It may be separated from the anthracene oil by repeated fractional distillation, followed by fractional crystallization from alcohol (anthracene being the less soluble), and finally purified by oxidizing any residual anthracene with potassium bichromate and sulphuric acid (R. Anschutz and G. Schultz, Ann., 1879, 196, p. 35); or the two hydrocarbons may be separated by carbon bisulphide, in which anthracene is insoluble. It is formed when the vapours of toluene, stilbene, dibenzyl, ortho-ditolyl, or coumarone and benzene are passed through a red-hot tube; by distilling morphine with zinc dust; and, with anthracene, by the action of sodium on ortho-brombenzyl bromide (C. L. Jackson and J. F. White, Amer. Chem. Jour., 1880, 2, p. 391). It crystallizes in colourless plates or needles, which melt at 99 C. Its solutions in alcohol and ether have a faint blue fluorescence. When heated to 250 C. with red phosphorus and hydriodic acid it gives a hydride Cu H^. It is nitrated by nitric acid and sulphonated by sulphuric acid. With picric acid it forms a sparingly soluble picrate, which melts at 145 C. On the condition of phenanthrene in alcoholic solution see R. Behrend, Zeit. phys. Chem., 1892, 9, p. 405; 10, p. 265. Chromic acid oxidizes phenanthrene, first to phenanthrene-quinone, and then to diphenic acid, HOzC-CeH^rL.-^!!.
Phenanthrene-quinone, [CeH^tCO^, crystallizes in orange needles which melt at 198 C. It possesses the characteristic properties of a diketone, forming crystalline derivatives with sodium bisulphite and a dioxime with hydroxylamine. It is non-volatile in steam, and is odourless. Sulphurous acid reduces it to the corresponding dihydroxy compound. It combines with ortho-diamines, in the presence of acetic acid, to form phenazines.
On the constitution of phenanthrene see CHEMISTRY: Organic.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)