NAPHTHALENE, or NAPHTHALIN, a coal-tar product consisting of carbon and hydrogen, with the chemical composition G.H. and a certain chemical similarity to benzene.
Its peculiar chemical composition may be repre sented by the graphic formula known as the condensed benzine rings, as below. These are generally written without the letter symbols, as at b.
Naphthalene is prepared from the middle or acarbolic" oil obtained in the distillation of coal tar between the boiling point temperatures of 410° and 460° F. The naphthaline crystallizes out on cooling, is then centrifugalized, pressed, warmed, stirred with caustic soda after the addition of sulphuric acid and several wash ings with hot water, is either sublimated or distilled. Physically, naphthalene is a white solid, with brilliant, leafy crystals, melting at 175° F. to a colorless liquid, which boils at 425° F. It burns with a sooty flame and
pitchy odor. It is insoluble in cold water, slightly soluble in water at a higher tempera ture and easily in the essences, in boil ing alcohol or in ether. Naphthalene forms a multitude of various compounds, mostly by simple addition i the most important are the various sulphonic acids, such as CialtSOM ILO, used in the manufacture of dyes. The nitro-derivatives of naphthalene are also ex tensively used as intermediates in dye-making. Under the popular name of 'moth balls* or acoal-tar camphor,' naphthalene is used to keep moths and other insects from clothes. It vaporizes slowly with no residue, and is useful to some extent as a disinfectant and deodorizer. Consult Tinkler, C. K., and Challenger, F., The Chemistry of Petroleum and Its Substitutes,' (New York 1915).