Acrylonitrile
Encyclopedia
Acrylonitrile is the chemical compound
with the formula C3H3N. This pungent-smelling colorless liquid often appears yellow due to impurities. It is an important monomer
for the manufacture of useful plastic
s. In terms of its molecular structure, it consists of a vinyl
group linked to a nitrile
. Pathways of exposure include emissions, auto exhaust, and cigarette smoke that can expose the human subject directly if they inhale or smoke. Routes of exposure include inhalation, oral, and occasional dermal routes from volunteer humans and rat studies.
to prepare the polyacrylonitrile
, a homopolymer, or several important copolymers such as styrene-acrylonitrile (SAN), acrylonitrile butadiene styrene
(ABS), acrylonitrile styrene acrylate (ASA) and other synthetic rubber
s such as acrylonitrile butadiene
(NBR). Dimerization of acrylonitrile affords adiponitrile
, used in the synthesis of certain polyamide
s. Small amounts are also used as a fumigant. Acrylonitrile and derivatives such as 2-chloro-acrylonitrile are dienophiles in Diels-Alder reaction
s. Acrylonitrile is also a precursor in the industrial manufacture of acrylamide
and acrylic acid
.
of propene:
. The burning material releases fumes of hydrogen cyanide and oxides of nitrogen
. The International Agency for Research on Cancer (IARC) concluded that there is inadequate evidence in humans for the carcinogenicity of acrylonitrile, but classified it as a Class 2B carcinogen (possibly carcinogenic). Acrylonitrile increases cancer in high dose tests in male and female rats and mice.
There are two main excretion processes of acrylonitrile. The primary method is excretion in urine when acrylonitrile is metabolized by being directly conjugated to glutathione
. The other method is when acrylonitrile is metabolized with 2-cyanoethylene oxide to produce cyanide
end products that ultimately forms thiocyanate
, which is excreted via urine, or carbon dioxide
and eliminated through the lungs.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula C3H3N. This pungent-smelling colorless liquid often appears yellow due to impurities. It is an important monomer
Monomer
A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
for the manufacture of useful plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
s. In terms of its molecular structure, it consists of a vinyl
Vinyl
A vinyl compound is any organic compound that contains a vinyl group ,which are derivatives of ethene, CH2=CH2, with one hydrogen atom replaced with some other group...
group linked to a nitrile
Nitrile
A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...
. Pathways of exposure include emissions, auto exhaust, and cigarette smoke that can expose the human subject directly if they inhale or smoke. Routes of exposure include inhalation, oral, and occasional dermal routes from volunteer humans and rat studies.
Uses
Acrylonitrile is used principally as a monomerMonomer
A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
to prepare the polyacrylonitrile
Polyacrylonitrile
Polyacrylonitrile is a synthetic, semicrystalline organic polymer resin, with the linear formula n. Though it is thermoplastic, it does not melt under normal conditions. It degrades before melting. It melts above 300 degrees Celsius only if the heating rates are 50 degrees per minute or above...
, a homopolymer, or several important copolymers such as styrene-acrylonitrile (SAN), acrylonitrile butadiene styrene
Acrylonitrile butadiene styrene
Acrylonitrile butadiene styrene is a common thermoplastic. Its melting point is approximately 105 °C ....
(ABS), acrylonitrile styrene acrylate (ASA) and other synthetic rubber
Synthetic rubber
Synthetic rubber is is any type of artificial elastomer, invariably a polymer. An elastomer is a material with the mechanical property that it can undergo much more elastic deformation under stress than most materials and still return to its previous size without permanent deformation...
s such as acrylonitrile butadiene
Nitrile rubber
Nitrile rubber, also known as Buna-N, Perbunan, or NBR, is a synthetic rubber copolymer of acrylonitrile and butadiene. Trade names include Nipol, Krynac and Europrene....
(NBR). Dimerization of acrylonitrile affords adiponitrile
Adiponitrile
Adiponitrile is the organic compound with the formula 42. This dinitrile, a viscous, colourless liquid, is an important precursor to the polymer nylon 66. In 2005, about one billion kilograms were produced annually.-Early routes:...
, used in the synthesis of certain polyamide
Polyamide
A polyamide is a polymer containing monomers of amides joined by peptide bonds. They can occur both naturally and artificially, examples being proteins, such as wool and silk, and can be made artificially through step-growth polymerization or solid-phase synthesis, examples being nylons, aramids,...
s. Small amounts are also used as a fumigant. Acrylonitrile and derivatives such as 2-chloro-acrylonitrile are dienophiles in Diels-Alder reaction
Diels-Alder reaction
The Diels–Alder reaction is an organic chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system. The reaction can proceed even if some of the atoms in the newly formed ring are not carbon...
s. Acrylonitrile is also a precursor in the industrial manufacture of acrylamide
Acrylamide
Acrylamide is a chemical compound with the chemical formula C3H5NO. Its IUPAC name is prop-2-enamide. It is a white odourless crystalline solid, soluble in water, ethanol, ether, and chloroform. Acrylamide is incompatible with acids, bases, oxidizing agents, iron, and iron salts...
and acrylic acid
Acrylic acid
Acrylic acid is an organic compound with the formula CH2=CHCO2H. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols,...
.
Production
Of all the nitriles, Acrylonitrile is manufactured on probably the largest scale. Most industrial acrylonitrile is produced by catalytic ammoxidationAmmoxidation
In chemistry, ammoxidation is an industrial process for the production of nitriles using ammonia and oxygen. The usual substrates are alkenes. It is sometimes called the Sohio process, acknowledging that ammoxidation was commercialized by Standard Oil of Ohio...
of propene:
- 2CH3-CH=CH2 + 2NH3AmmoniaAmmonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
+ 3O2OxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
→ 2CH2=CH-C≡N + 6H2OWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
Health effects
Acrylonitrile is highly flammable and toxic. It undergoes explosive polymerizationPolymerization
In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...
. The burning material releases fumes of hydrogen cyanide and oxides of nitrogen
Nitrogen dioxide
Nitrogen dioxide is the chemical compound with the formula it is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...
. The International Agency for Research on Cancer (IARC) concluded that there is inadequate evidence in humans for the carcinogenicity of acrylonitrile, but classified it as a Class 2B carcinogen (possibly carcinogenic). Acrylonitrile increases cancer in high dose tests in male and female rats and mice.
There are two main excretion processes of acrylonitrile. The primary method is excretion in urine when acrylonitrile is metabolized by being directly conjugated to glutathione
Glutathione
Glutathione is a tripeptide that contains an unusual peptide linkage between the amine group of cysteine and the carboxyl group of the glutamate side-chain...
. The other method is when acrylonitrile is metabolized with 2-cyanoethylene oxide to produce cyanide
Cyanide
A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
end products that ultimately forms thiocyanate
Thiocyanate
Thiocyanate is the anion [SCN]−. It is the conjugate base of thiocyanic acid. Common derivatives include the colourless salts potassium thiocyanate and sodium thiocyanate. Organic compounds containing the functional group SCN are also called thiocyanates...
, which is excreted via urine, or carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
and eliminated through the lungs.