nitrilien

Nitriles are organic compounds that contain the cyano group, a carbon triple-bonded to nitrogen, written as -C≡N. The general formula is a molecule of the form R-CN, where R is an alkyl or aryl group. The cyano group is highly polar, which gives nitriles distinctive physical properties and makes them useful as solvents and reactive intermediates. Nitriles are named by replacing the suffix -ane with -nitrile in the parent hydrocarbon, with acetonitrile and benzonitrile among the most common examples.

Synthesis and production methods vary. Nitriles can be prepared by dehydrating primary amides (R-CONH2) using dehydrating agents such as phosphoryl chloride or highly active acids. They can also be formed by cyanation of alkyl halides (R-X + NaCN). Industrially important routes include ammoxidation of alkenes, such as propene to acrylonitrile, and hydrocyanation of alkenes under appropriate catalysts. These methods enable large-scale production for use as intermediates in further synthesis.

Properties and reactions of nitriles reflect the polar cyano group. They are relatively stable under many conditions but undergo hydrolysis to carboxylic acids or amides under acidic or basic conditions. Nitriles can be reduced to primary amines via catalytic hydrogenation. They can also participate in various condensation and addition reactions that generate a wide range of downstream products. Some nitriles, particularly simple organics like acetonitrile, are common laboratory solvents.

Applications are broad. Acrylonitrile is a key monomer for polyacrylonitrile fibers and related polymers used in textiles and plastics. Nitrile-containing compounds serve as solvents, intermediates in pharmaceutical and agrochemical syntheses, and precursors to speciality chemicals. Nitrile rubbers, with enhanced oil resistance, are widely used in seals and hoses.

Safety and environmental considerations are important. Many nitriles are toxic and can release hydrogen cyanide under certain conditions, especially upon combustion or strong hydrolysis. Appropriate ventilation, handling, and disposal practices are required to minimize risk.