Pyrene

Pyrene, C16H10, a hydrocarbon found together with chrysene in the last portion of the coal tar distillate, and also in "Stupp" fat.

The crude solid product from the tar distillate is digested with carbon bisulphide to dissolve the pyrene, the solution filtered and the solvent evaporated. The residue is dissolved in alcohol and to the cold saturated solution a cold alcoholic solution of picric acid is added. The picrate so formed is then decomposed by ammonia. On its separation from "Stupp" fat see E. Bamberger and M. Philip, Ann., 1887, 240, p. 161. It crystallizes in monoclinic tables which melt at 148-149° C. Chromic acid oxidizes it to pyrene quinone, C16H802, and pyrenic acid, C15H1806. The picrate, which is easily soluble in benzene, crystallizes in long red needles melting at 222°. When heated with hydriodic acid and phosphorus to 200° C. it yields a hexahydride. It has been obtained synthetically by M. Freund and H. Michaels (Ber., 1897, 30, p. 1383) by distilling thebenol over zinc dust in a stream of hydrogen, or by the action of hydriodic acid and phosphorus at 220° C. on thebenol.