The petrochemical industry supplies semi-finished products, that are obtained from methane or hydrocarbons produced by petroleum distillation. Typical processes are: nitric acid, sulfuric acid, methanol, urea and styrene syntesis; aromatic molecules (benzene, toulene and xylene); production of nitriles; production of halogenated hydrocarbons. Later on, all these substances are used as raw materials for the synthesis of other molecules.