organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J ...

, ammoxidation is a process for the production of

nitrile In organic chemistry, a nitrile is any organic compound that has a functional group. The prefix '' cyano-'' is used interchangeably with the term ''nitrile'' in industrial literature. Nitriles are found in many useful compounds, including me ...

s () using

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...

() and

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...

(). It is sometimes called the SOHIO process, acknowledging that ammoxidation was developed at

Standard Oil of Ohio The Standard Oil Company (Ohio) was an American oil company, a successor of the original company established in 1870 by John D. Rockefeller. It was established as "Standard Oil Company of Ohio" as one of the separate entities created after t ...

. The usual substrates are

alkene In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic ...

s. Several million tons of

acrylonitrile Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions. In terms of its molecula ...

are produced in this way annually: :CH3CH=CH2 + 3/2 O2 + NH3 -> N#CCH=CH2 + 3 H2O

Scope

Ammoxidation of alkenes exploits the weak C-H bonds that are located in the

allyl In organic chemistry, an allyl group is a substituent with the structural formula , where R is the rest of the molecule. It consists of a methylene bridge () attached to a vinyl group (). The name is derived from the scientific name for garlic, ...

ic position of unsaturated hydrocarbons.

Benzyl In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure . Benzyl features a benzene ring () attached to a methylene group () group. Nomenclature In IUPAC nomenclature, the prefix benzyl refers to a substi ...

ic C-H bonds are also susceptible to ammoxidation, reflecting the weakness of their C-H bonds. Benzonitrile is produced from toluene, and phthalonitriles are produced from

xylene In organic chemistry, xylene or xylol (; IUPAC name: dimethylbenzene) are any of three organic compounds with the formula . They are derived from the substitution of two hydrogen atoms with methyl groups in a benzene ring; which hydrogens are s ...

s. The reaction represents a partial oxidation. Many byproducts are generated, but the feedstocks are often simple, which compensates for these losses. Additionally, some byproducts are useful or recyclable. For the production of acrylonitrile, byproducts include

hydrogen cyanide Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on a ...

acrolein Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colorless liquid with a piercing, acrid smell. The smell of burnt fat (as when cooking oil is heated to its smoke point) is caused by glycerol in the burning fat ...

, and the solvent

acetonitrile Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula and structure . This colourless liquid is the simplest organic nitrile ( hydrogen cyanide is a simpler nitrile, but the cyanide anion is not clas ...

. The reaction tolerates heteroatoms and substituents. Cyanopyridines (e.g. 3-cyanopyridine, the precursor to

niacin Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variet ...

) is produced from methyl

pyridine Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid w ...

s. 2- and

4-Chlorotoluene Chlorotoluene is a group of three isomeric chemical compounds. They (''ortho''-chlorotoluene, ''meta''-chlorotoluene, and ''para''-chlorotoluene) consist of a disubstituted benzene ring with one chlorine atom and one methyl group. Properties The ...

are converted to 2-chlorobenzonitrile and 4-chlorobenzonitrile, respectively.{{Ullmann, doi=10.1002/14356007.a17_363, title=Nitriles, year =2000, last1=Pollak, first1=Peter, last2=Romeder, first2=Gérard, last3=Hagedorn, first3=Ferdinand, last4=Gelbke, first4=Heinz-Peter, isbn=3527306730 Typical catalysts are the oxides of vanadium and molybdenum. The original catalyst discovered at Sohio was bismuth phosphomolybdate (BiPMo₁₂O₄₀). π-Allyl complexes are assumed as intermediates.Nugent, W. A.; Mayer, J. M., Metal-Ligand Multiple Bonds. J. Wiley: New York, 1988.

Related processes

Instead of alkenes,

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

s and

aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl gro ...

s are competent substrates: :O=CHCH=CH2 + 1/2 O2 + NH3 -> N#CCH=CH2 + 2 H2O :HOCH2CH=CH2 + O2 + NH3 -> N#CCH=CH2 + 3 H2O These substrates are usually more expensive than the alkenes, so they are less common. The

nitrile process In chemistry, a fatty amine is loosely defined as any amine possessing a mostly linear hydrocarbon chain of eight or more carbon atoms. They are typically prepared from the more abundant fatty acids, with vegetable or seed-oils being the ultimat ...

is used industrially to produce nitriles from fatty acids: : RCOOH + NH3 -> RC#N + 2 H2O

Hydrogen cyanide Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on a ...

is prepared by an ammoxidation-like reaction of methane, the Andrussov oxidation: :CH4 + NH3 + 3/2 O2 -> HCN + 3 H2O

References

Industrial processes Chemical reactions

Scope

Related processes

See also

References