What are the 200 substances present in coal-tar?
There is a huge range of chemicals derived from coal tar distillation. The main product (approx. 50 %) of the tar refinery is the distillation residue "coal tar pitch". The distillates are crude naphthalene and technical fractions (aromatic oils). The major single coumpounds are naphthalene (~10 %), phenanthrene (~4,5 %) and anthracene (~1,3 %). Some compounds (e.g. naphthalene, anthracene, carbazole, phenol, cresols and xylenols) are commercially available from coal tar distillation.
Coal-tar is complex & is mainly made of mixture of phenols,polycyclic aromatic hdrocarbons & heterocyclic compounds.By the distillstion of coal tar first of all we get carbon & then we get benzene, toluene ,xylene, napthalene, piridine, naphthol, cresol , anthracene & phenonthrene.The residue left after distillation is called pitch.