Azines are a functional class of

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

s with the connectivity . These compounds are the product of the condensation of

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

with

ketones In organic chemistry, a ketone is an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone ( ...

and

aldehydes 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 ...

, although in practice they are often made by alternative routes. Ketazines are azines derived from ketones. For example,

acetone azine Acetone azine is the simplest ketazine. It is an intermediate in some hydrazine manufacturing processes. Synthesis Acetone azine can be prepared from acetone and hydrazine: :2 (CH3)2CO + N2H4 → 2 H2O + CH3)2C=Nsub>2 It can also be produc ...

is the simplest ketazine. Aldazines are azines derived from aldehydes.

Preparation

The usual method of industrial production is the

peroxide process The peroxide process is a method for the industrial production of hydrazine. In this process hydrogen peroxide is used as an oxidant instead of sodium hypochlorite, which is traditionally used to generate hydrazine. The main advantage of the pero ...

, starting from the ketone,

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

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

. :

In the laboratory, azines are typically prepared by condensation of hydrazine with two equivalents of a carbonyl. Azines are also produced when

chalcone Chalcone is the organic compound C6H5C(O)CH=CHC6H5. It is an α,β-unsaturated ketone. A variety of important biological compounds are known collectively as chalcones or chalconoids. They are widely known bioactive substances, fluorescent materi ...

reacts with a

hydrazone Hydrazones are a class of organic compounds with the structure . They are related to ketones and aldehydes by the replacement of the oxygen =O with the = functional group. They are formed usually by the action of hydrazine on ketones or aldehydes. ...

to produce 3,5-diphenyl-1''H''-

pyrazole Pyrazole is an organic compound with the chemical formula, formula . It is a heterocycle characterized as an azole with a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in Arene substitution pattern, ortho-substi ...

, in a conversion also carried out with

hydrazine hydrate Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

. :

Reactions

Azines characteristically undergo hydrolysis to hydrazines. The reaction proceeds by the intermediacy of a hydrazone: : : Azines have been used as precursors to

s: : They are also precursors to diazo compounds.. Acetone azine chem

The

coordination chemistry A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...

of azines (as

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

s) has also been studied.

Acetone Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ...

is used to derivatize hydrazine into

for analysis by

gas chromatography Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for Separation process, separating and analyzing compounds that can be vaporized without Chemical decomposition, decomposition. Typical uses of GC include t ...

. This method is used to determine trace levels of hydrazine in drinking water and pharmaceuticals.

Applications

Ketazines are also important intermediates in the industrial production of hydrazine hydrate by the

.Jean-Pierre Schirmann, Paul Bourdauducq "Hydrazine" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. . In the presence of an

oxidant An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or "Electron acceptor, accepts"/"receives" an electron from a (called the , , or ''electr ...

, ammonia and ketones react to give hydrazine via ketazine: :2 Me(Et)C=O + 2 NH₃ + H₂O₂ → Me(Et)C=NN=C(Et)Me + 2 H₂O The ketazine can be hydrolyzed to the hydrazine and regenerate the ketone: :Me(Et)C=NN=C(Et)Me + 2 H₂O → 2 Me(Et)C=O + N₂H₄ Ketazines have been also used as sources of hydrazine produced ''in situ'', for example in the production of

herbicide Herbicides (, ), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...

precursor 1,2,4-triazole..

Preparation

Reactions

Applications

References

Further reading