coal tar

Coal tar is a dense, black, viscous, volatile liquid produced by the destructive distillation of coal; coke and coal gas are other products. Fractional distillation of coal tar produces a wide variety of industrially important substances. These include asphalt and creosote, a wood preservative; also various oils used as fuels, solvents, preservatives, lubricants (see lubrication), and disinfectants. Specific chemicals that can be isolated include benzene, toluene, xylene, phenol, pyridine, naphthalene, and anthracene – the main source for the pharmaceutical and other chemical industries.