FLUORANTHENE, known also as idryl, a solid hydrocar bon occurring with phenanthrene, pyrene, diphenyl, chrysene and other substances in "Stupp" fat (obtained in working up the mer cury ores in Idria), and also in the higher boiling fractions of the coal tar distillate. Fluoranthene, C15H1o, was discovered by R. Fittig in 1878, who, with F. Gebhardt and H. Liepmann, elucidated its constitution. From the tar distillate the chrysene can be frac tionally precipitated, and the fluoranthene can be separated from most of the pyrene by fractional distillation in a partial vacuum. The two latter hydrocarbons are finally separated by fractional crystallization of their picrates. Fluoranthene crystallizes in large slender needles or monoclinic tables, melting at 109-110° C and boiling at C (6omm.). On oxidation with chromic acid it forms a quinone, and an a-diphenyleneketo carboxylic acid.
See A. E. Everest, The Higher Coal Tar Hydrocarbons (1927). FLUORENE (ortho-diphenylene methane), is a hydrocarbon, obtained from coal tar, where it was first discovered by M. Berthelot in 1867. The "carbolic oil" fraction, after removal of naphthalene and anthracene, is distilled, the greater portion of the fluorene coming over between 295° and C. Separation from other constituents may be effected through its solid potassium compound by fusion with caustic potash at 280° C. Addition of water regenerates the fluorene, which is further purified through its picrate or by crystallization, when it forms white, lustrous laminae, melting point 115° C, boiling point 295° C.
Oxidation with chromic acid yields fluorenone (diphenylene ketone) yellow prisms, melting at 84°C, but with potassium permanganate as oxidizing agent the molecule is broken down, giving phthalic acid (q.v.). The positions taken up in fluorene by entering substit uents are controlled by the influence of the phenylene nuclei one upon the other, and not at all by the methylene group (contrast carbazole, q.v.). Thus on dinitration the nitro-groups replace the hydrogen atoms ortho and para to the single bond which directly unites the two nuclei, to give 2:5- and 2 :7-dinitrofluorene. 2 :7-Diaminofluorene has been used in the preparation of azo-dyes which, like those from benzidine, possess affinity for unmordanted cotton, but they have not yet found commercial application. When fluorene is reduced with hydriodic acid, decahydrofluorene, is produced other hydrogenated fluorenes are also known.
(H. A. HA.)