Acetonitrile[2]
Overview
Acetonitrile is a nitrile compound derived from acetic acid, primarily produced as a byproduct of acrylonitrile manufacturing. Its unique combination of polarity, chemical stability, and miscibility with both organic and aqueous phases has made it indispensable in modern laboratories and industries. As a solvent, it effectively dissolves a wide range of organic and inorganic compounds while maintaining low UV absorbance—a critical property for analytical applications. The global market for acetonitrile is closely tied to pharmaceutical production, consuming over 60% of total output.
Physical and Chemical Properties
Acetonitrile exhibits a narrow liquid range (-45°C to 82°C) with a characteristic ether-like odor at high concentrations. Its dipole moment of 3.92 D and dielectric constant of 37.5 enable superior solvation of ionic compounds compared to many organic solvents. The solvent demonstrates remarkable chemical stability, resisting hydrolysis in neutral or acidic conditions. However, strong bases may cause decomposition to hydrogen cyanide. Its azeotropic mixture with water (84% acetonitrile, 16% water) boils at 76°C, complicating certain purification processes.
Main Applications
In analytical chemistry, acetonitrile is the preferred mobile phase for reversed-phase HPLC due to its low viscosity, UV transparency, and excellent peak resolution capabilities. Pharmaceutical manufacturers utilize it as a reaction medium for antibiotics, vitamins, and insulin production. The electronics industry employs high-purity grades in lithium-ion battery electrolytes and semiconductor cleaning. Other uses include DNA synthesis, pesticide formulation, and as a polar aprotic solvent in organic reactions like the Ritter reaction and nucleophilic substitutions.
Safety and Storage
Classified as a flammable liquid (Category 2) and health hazard (Category 3), acetonitrile requires careful handling. Its vapor is heavier than air and can travel considerable distances to ignition sources. Chronic exposure may cause thyroid dysfunction due to thiocyanate formation. Storage recommendations include using grounded conductive containers in temperature-controlled areas (<30°C) with explosion-proof electrical fittings. Spill containment should utilize non-combustible absorbents like vermiculite, never activated carbon which may combust spontaneously.
B2B Procurement Guide
Industrial buyers should specify technical (≥98%), HPLC (≥99.9%), or ultra-HPLC grades based on application needs. Bulk shipments typically use 200L epoxy-lined steel drums or isotanks for quantities exceeding 1,000kg. Key quality indicators include water content (<0.1% for HPLC), UV cutoff (190nm for gradient grade), and residue after evaporation (<5ppm). Asian markets often offer competitive pricing, but verify ISO 9001 certification and REACH compliance documentation for European imports.