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Nitriles are a class of organic compounds characterized by the cyano functional group, a carbon triple-bonded to nitrogen (−CN). The general structure is R−CN, where R is a hydrocarbon or other substituent. The cyano group is a strong electron-withdrawing group, giving nitriles distinct polarity and reactivity compared with many other hydrocarbon derivatives.

Nitriles include simple aliphatic nitriles such as acetonitrile (CH3CN) and propionitrile, as well as aromatic nitriles like benzonitrile. They are typically colorless liquids or solids at room temperature and often have characteristic, pungent odors. Nitriles are widely used as solvents and as versatile building blocks in organic synthesis and industrial chemistry.

Synthesis of nitriles occurs through several common routes. One standard method is the nucleophilic substitution of alkyl halides with cyanide sources (R−X + NaCN → R−CN). Nitriles can also be prepared by dehydration of primary amides (RCONH2 → R−CN) using dehydrating reagents such as thionyl chloride, phosphorus oxychloride, or related species. A route from aldehydes or ketones involves the formation of oximes (R-CH=NOH) followed by dehydration to nitriles (R−CHN). Nitriles can also arise as intermediates in various cyanation and multistep processes.

Applications of nitriles are broad. Acetonitrile is a widely used laboratory solvent and reaction medium, particularly in chromatography. Nitriles serve as precursors for pharmaceuticals, agrochemicals, and dyes. In polymer chemistry, polyacrylonitrile (PAN) is a key fiber material, and acrylonitrile is a principal monomer for various plastics and nitrile rubber formulations. Nitrile-containing compounds are also encountered in specialty chemicals and materials.

Safety considerations are important, as many nitriles are toxic and can release hydrogen cyanide under acidic conditions; proper handling, ventilation, and waste management are essential in their use and production.