cyanomethane

Cyanomethane, also known as acetonitrile (ethanenitrile), is an organic nitrile with the formula C2H3N. It is a colorless, volatile liquid used widely as a polar aprotic solvent in laboratory and industrial settings. It has a boiling point of 81.6°C, a melting point around -45°C, and a density near 0.786 g/mL at 20°C. It is miscible with water and with many organic solvents, and it features a relatively high dielectric constant, reflecting its polarity.

Production and occurrence: Industrial production of acetonitrile occurs primarily as a byproduct of acrylonitrile manufacture via ammoxidation of propylene. It can also be produced or concentrated by dehydration of acetamide. In practice, acetonitrile is often recovered from reactor effluents and purified by distillation for commercial use.

Applications: Acetonitrile is a versatile solvent in organic synthesis, chromatography, and analytical chemistry. It is commonly used in high-performance liquid chromatography (HPLC) and as a solvent for nucleophilic substitutions, enzyme reactions, and phase-transfer processes. It serves as a stock solvent in pharmaceutical and photographic industries and is a precursor in various nitrile- and dye-related syntheses.

Safety and handling: Acetonitrile is hazardous if ingested or inhaled; exposure can cause irritation, headaches, dizziness, or more serious effects at higher doses. It is metabolized to cyanide in the body, contributing to its toxicity. It is flammable and should be handled with appropriate engineering controls and personal protection in a well-ventilated area. Environmental exposure should be minimized, as it is water-soluble and can affect aquatic life.