Acetonitril

Acetonitril, also known as acetonitrile (IUPAC name ethanenitrile), is a colorless, volatile, highly polar aprotic solvent with the chemical formula CH3CN. It is widely used in organic synthesis and as an intermediate in the production of polymers, pharmaceuticals, and agrochemicals. It is miscible with water and many organic solvents. Its boiling point is 81.6 °C, melting point −45.7 °C, and it has a density of about 0.786 g/mL at 25 °C. It is flammable and has a flash point around −17 °C.

Industrial production occurs principally as a byproduct of the ammoxidation of propylene to acrylonitrile, where propylene, ammonia, and oxygen react over a catalyst. The acetonitrile is separated and purified from the reaction mixture. While alternative routes exist, the acrylonitrile process remains the major source of commercially produced acetonitrile.

Applications include its role as a versatile solvent in organic chemistry due to its high dielectric constant and broad solvating power. It is used in the manufacture of polymers, pharmaceuticals, dyes, and agrochemicals, and serves as a solvent and mobile phase component in gas chromatography (GC) and high-performance liquid chromatography (HPLC).

Safety and handling notes: acetonitrile is flammable and moderately toxic. Inhalation, ingestion, or skin exposure can cause irritation and central nervous system effects; metabolism can release cyanide, contributing to toxicity at higher exposures. It should be stored in a cool, well-ventilated area in tightly closed containers, away from oxidizers and heat. Handling generally requires appropriate containment and personal protective equipment, with disposal following applicable hazardous-wacards or local regulations.