Coal Tar

Coal tar is a source of polycyclic aromatic hydrocarbons, including naphthalene, phenanthrene and pyrene. It also yields phenols, among them phenol and cresols, and nitrogen heterocycles such as pyridine, picolines, carbazole and quinolines. The composition of coal tar varies with coal type and processing, but typical coal tar is about 10% naphthalene by weight. Several of these compounds serve as starting materials for dyes, tartrazine among them, and for photographic materials.

The major uses of coal tars are carbon-based electrodes for aluminium processing, wood preservatives, resins for paints and coatings, and as a source of valuable organic compounds. Fractional distillation of coal tar recovered tar for roads, benzole as a motor fuel, creosote as a wood preservative, phenol for plastics and cresols as disinfectants. A creosote rich in naphtha smells of naphtha; with less naphtha it smells more of tar. Some phenolic coal tar derivatives have analgesic properties, among them acetanilide, phenacetin and paracetamol. Although not common, coal tar is used topically for relief from some skin conditions. As of 2011, 30 million tons of coal tar were obtained per year, half of which was processed as a source of chemicals.

The use of coal tar in cosmetic products was forbidden in the European Union by a directive in 2009. The residue from the distillation of high-temperature coal tar is classed as a substance of very high concern by the European Chemicals Agency.

Related: Amberwood · Andiroba · Bakhoor · Balsamic Notes · Benzoin Resinoid · Benzyl Benzoate · Benzyl Salicylate · Birch Tar