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

, ammoxidation is a process for the production of

nitrile In organic chemistry, a nitrile is any organic compound that has a functional group. The name of the compound is composed of a base, which includes the carbon of the , suffixed with "nitrile", so for example is called " propionitrile" (or pr ...

s () using

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

() and

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

(). 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 petroleum industry, petroleum company that existed from 1870 to 1987. The company, known commonly as Sohio, was founded by John D. Rockefeller. It was established as one of the separate entities cre ...

. The usual substrates are

alkene In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as Alpha-olefin, α-olefins. The Internationa ...

s. Several million tons of

acrylonitrile Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an im ...

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 . It consists of a methylene bridge () attached to a vinyl group (). The name is derived from the scientific name for garlic, . In 1844, Theodor Wertheim isolated a ...

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 (). Nomenclature In IUPAC nomenclature, the prefix benzyl refers to a substituent ...

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 cherry or almond like odour. It is mainly used industrially to produce the melamine resin precursor benzoguanam ...

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 su ...

s. The reaction represents a

partial oxidation Partial oxidation (POX) is a type of chemical reaction. It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use, for example in a fuel cell. A d ...

. 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 (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...

, acrolein, 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 class ...

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

niacin Nicotinic acid, or niacin, is an organic compound and a vitamer of vitamin B3, an essential human nutrient. It is produced by plants and animals from the amino acid tryptophan. Nicotinic acid is also a prescription medication. Amounts f ...

) is produced from methyl

pyridine Pyridine is a basic (chemistry), basic heterocyclic compound, 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, weak ...

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 Vanadium is a chemical element; it has Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an ...

and

molybdenum Molybdenum is a chemical element; it has Symbol (chemistry), symbol Mo (from Neo-Latin ''molybdaenum'') and atomic number 42. The name derived from Ancient Greek ', meaning lead, since its ores were confused with lead ores. Molybdenum minerals hav ...

. 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 may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

s and

aldehyde In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...

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

Hydrogen cyanide Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...

is prepared by an ammoxidation-like reaction of

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

, the Andrussov oxidation: :CH4 + NH3 + 3/2 O2 -> HCN + 3 H2O

References

Industrial processes Chemical reactions

Scope

Related processes

See also

References