A large group of chemicals distinct from fuels derived from petroleum and natural gas and used for a variety of commercial purposes are called Petrochemicals. The whole range of aliphatic, aromatic, and naphthenic organic chemicals, as well as carbon black and Inorganic materials such as sulfur and ammonia are included in it. A specific chemical included among the petrochemicals in many instances may also be obtained from other sources such as coal, coke or vegetable products. Materials like benzene and naphthalene can be made from either petroleum or coal, while ethyl alcohol may be of petrochemical or vegetable origin. This makes it difficult to categorize a specific substance as petrochemical or Non petrochemical.
