Nitrile

Nitrites are a group of chemical compounds having the general formula RC ≡ N. The functional group of carbon and triply bonded nitrogen is referred to as nitrile or cyano group. The nitriles are formally derived from the hydrogen cyanide ( HCN) by replacement of the hydrogen atom by an organic radical from. The isomers with the formula RN ≡ C is called isonitriles.

Nitrile polymers are chemically very stable and have rubber-like properties, which is why they are used eg for protective gloves.

Nomenclature

It uses either the prefix " cyan " or the suffix " -nitrile ". According to the rules of nomenclature of functional groups, the appointment shall be made as " Alkannitril " when the cyano group is the functional group with the highest ranking. Otherwise, the prefix " cyan " is used. According to their relationship with the carboxylic acids ( the Nitrilkohlenstoff has the same oxidation state as the carboxyl carbon ), many nitriles are trivial as " Carboxylonitrile " means, for example, acetonitrile, propionitrile, butyronitrile, Mandelonitrile.

Production

Nitrites are produced industrially by hydrocyanation ( addition of HCN to alkenes ), and by the catalytic oxidation of alkenes and ammonia with air.

On a laboratory scale nitriles may be prepared by reaction of alkali metal cyanide ( alkali metal salts of hydrogen cyanide ) with an alkyl halide ( Kolbe- nitrile ). Here, the Alkannitril and an alkali halide is formed. By-products of isonitriles. The reaction of methyl iodide with sodium cyanide to acetonitrile and sodium iodide was given as an example for this reaction:

Other possibilities are the dehydration of aldoximes with, for example phosphorus pentachloride, PCl5, analogous to a Beckmann rearrangement, or the implementation of Metallthiocyanaten with carboxylic acids known as Letts nitrile synthesis.

The preparation of aryl nitriles is achieved by the

• Sandmeyer reaction ( diazotization of aniline derivatives and reaction with copper ( I) cyanide )
• Rosenmund -von Braun reaction ( direct reaction of an aryl bromide with copper ( I) cyanide )

Reactions

Hydrolysis of nitriles can be produced carboxylic acids.

Furthermore, one can produce a nitrile, an amine by reduction (hydrogenation ).

Use

Especially adiponitrile and acrylonitrile are useful as intermediates in plastics production of practical importance.

An important role of nitrites is that you can easily insert into a chemical synthesis that group and then can convert into other functional groups (amino acids or amines). The process for preparation of α -amino acids from aldehydes, occur in the nitriles as intermediates is known as a Strecker synthesis.

Acetonitrile is used as solvent use.

In case of medical examination gloves are those made ​​of nitrile rubber superior latex allergy risk due to the lack those. As a material for protective gloves offers particularly good chemical resistance.