Acrylonitrile

Acrylonitrile is the chemical compound with the formula CH2CHCN. This pungent-smelling colorless liquid often appears yellow due to impurities. It is an important monomer for the manufacture of useful plastics. In terms of its molecular structure, it consists of a vinyl group linked to a nitrile.

Uses
Acrylonitrile is used principally as a monomer in the manufacture of synthetic polymers, especially polyacrylonitrile which comprises acrylic fibers. Acrylic fibers are, among other uses, precursor for well-known carbon-fiber. It is also a component of synthetic rubber. Dimerization of acrylonitrile affords adiponitrile, used in the synthesis of certain Nylons. Small amounts are also used as a fumigant. Acrylonitrile and derivatives such as 2-chloro-acrylonitrile are dienophiles in Diels-Alder reactions. Acrylonitrile is also a precursor in the industrial manufacture of acrylamide and acrylic acid.

Production
Acrylonitrile is probably the nitrile manufactured on the largest scale. Most industrial acrylonitrile is produced through the Sohio process, the catalytic ammoxidation of propylene:
 * 2CH3-CH=CH2 + 2NH3 + 3O2 → 2CH2=CH-C≡N + 6H2O

World annual production in 2001 was 4 million tonnes and in 2005 6 million tonnes, with just under half of that coming from the United States. In 1996 the Sohio acrylonitrile process was designated an ACS National Historical Chemical Landmark in recognition of the innovative single-step method of production that made acrylonitrile available for chemical manufacturing worldwide.

Safety
Acrylonitrile is highly flammable and toxic. It undergoes explosive polymerization. The burning material releases fumes of hydrogen cyanide and oxides of nitrogen. Acrylonitrile is classified as a possible human carcinogen (IARC group 2B).