Coal tar is produced during the pyrolysis of coal to make coke. The first tar-processing units appeared in Europe in the mid-19th century, and the business expanded rapidly in the first half of the 20th century.
The aromatic molecules present in the oils distilled from tars enabled the birth and development of industrial organic chemistry. The extraction of aromatic molecules such as benzene, toluene, naphthalene, phenol, cresols, pyridines, anthracene, carbazole, etc., laid the foundations for the modern chemical industry in a wide range of fields, including plastics, colorants, plant protection products, antioxidants, resins, surfactants and pharmaceuticals.
Today, the petrochemical industry has taken over, providing large quantities of molecules that the tar industry could no longer supply in sufficient volumes. Nevertheless, many of the products derived from tar still hold an attractive position in the industry, either because they have a qualitative advantage, as in the case of carbonaceous materials, or because their extraction costs are competitive.