Nitriles

Many of the compounds of this group are highly flammable, especially substances such as acrylonitrile and acetonitrile that have low flash points and relatively wide flammability concentration limits. All are combustible. The incomplete combustion of these materials produces significant amounts of gaseous hydrogen cyanide. When heated to decomposition, nitriles emit highly toxic fumes.

Nitriles may polymerize in the presence of metals and some metal compounds. They are incompatible with acids; mixing nitriles with strong oxidizing acids can lead to extremely violent reactions. Nitriles are generally incompatible with other oxidizing agents such as peroxides and epoxides. The combination of bases and nitriles can produce hydrogen cyanide. Nitriles are hydrolyzed in both aqueous acid and base to give carboxylic acids (or salts of carboxylic acids). These reactions generate heat. Peroxides convert nitriles to amides. Nitriles can react vigorously with reducing agents. Acetonitrile and propionitrile are soluble in water, but nitriles higher than propionitrile have low aqueous solubility. They are also insoluble in aqueous acids.

Pure alkyl nitriles are said to be only slightly toxic. Usually however they are contaminated with highly toxic isocyanides and should be treated as serious poisons. They are absorbed by inhalation, ingestion and by contact with the skin. Other nitriles vary in toxicity, with some approaching the inorganic cyanides in toxicity.

Compounds in this group are organic compounds containing the nitrile group (-CN). This group is also called the cyanide group. Probably the most important use of these materials is in the production of nitrile rubber, which is a copolymer of acetonitrile with butadiene. Nitriles such as cyanogen are used in organic synthesis, fumigants, and rocket propellant materials.

Acetonitrile, benzonitrile, butyronitrile, cyanoacetic acid, isobutyronitrile, lactonitrile, propionitrile.