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, ...

, ammoxidation is a process for the production of nitriles () 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 wa ...

() 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 as ...

(). It is sometimes called the SOHIO process, acknowledging that ammoxidation was developed at Standard Oil of Ohio. 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, an ...

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 allylic 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 Benzonitrile is the chemical compound with the formula , abbreviated PhCN. This aromatic organic compound is a colorless liquid with a sweet bitter almond odour. It is mainly used as a precursor to the resin benzoguanamine. Production It is p ...

is produced from toluene, and

phthalonitrile Phthalonitrile is an organic compound with the formula C6H4(CN)2, which is an off-white crystal solid at room temperature. It is a derivative of benzene, containing two adjacent nitrile groups. The compound has low solubility in water but is sol ...

s 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, acrolein, and the solvent acetonitrile. The reaction tolerates heteroatoms and substituents. Cyanopyridines (e.g.

3-cyanopyridine Nicotinonitrile or 3-cyanopyridine is an organic compound with the formula NCC5H4N. The molecule consists of a pyridine ring with a nitrile group attached to the 3-position. A colorless solid, it is produced by ammoxidation of 3-methylpyridine: ...

, 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 with a ...

s. 2- and 4-Chlorotoluene 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, alcohols 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 grou ...

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 is prepared by an ammoxidation-like reaction of methane, the

Andrussov oxidation The Andrussow process is an industrial process for the production of hydrogen cyanide from methane and ammonia in the presence of oxygen and a platinum catalyst. :2 CH4 + 2 NH3 + 3 O2 → 2 HCN + 6 H2O The process is based on a reaction ...

: :CH4 + NH3 + 3/2 O2 -> HCN + 3 H2O

References

Industrial processes Chemical reactions

Scope

Related processes

See also

References