Coal tar extracted from coal

Coal tar is a black viscous liquid, slightly heavier than water and a mixture of many organic compounds. Although there are many compounds in coal tar, most of them are very few. Naphthalene is the most important component in coal tar, with an average content of 10%, and only 10 compounds with a content above10.

Coal tar is an important organic chemical raw material, and its processing and refining is an important branch of modern coal chemical industry. Through processing and separation, dozens to hundreds of chemical products can be made. These products are raw materials for producing resins, dyes, medicines, pesticides, preservatives, explosives, vitamins, detergents, carbon black, waterproof coatings, dyeing auxiliaries and other products. Some of these raw materials cannot be produced and replaced by petrochemical industry at present. With the development of fine chemical industry in China, the position of coal tar in chemical industry will become more and more important.

Coal tar is made by dry distillation of coal after it is isolated from air and heated. The liquid product obtained in the process of coal dry distillation, that is, the tar obtained by high-temperature dry distillation (that is, coking), is called high-temperature dry distillation coal tar (short for high-temperature coal tar), and the tar obtained by low-temperature dry distillation (see low-temperature dry distillation of coal) is called low-temperature dry distillation coal tar (short for low-temperature coal tar). Their compositions and properties are different, and their processing and utilization methods are also different.