Acrylonitrile, stabilized hly

Physical Properties

• Appearance: Colorless, transparent liquid.
• Odor: Sweet, slightly pungent, and irritating odor.
• Melting Point: Approximately -83.5 °C.
• Boiling Point: Around 77.3 °C.
• Density: ~0.806 g/cm³ at 20 °C (lighter than water).
• Solubility: Slightly soluble in water (~7.4 g/100 mL at 20 °C), but highly miscible with most common organic solvents such as ethanol, ether, acetone, and benzene.
• Flash Point: Approximately -1 °C, making it a highly flammable liquid. Its vapors are heavier than air and can form explosive mixtures with air (explosive limits: 3.0%–17.0%).

Chemical Properties

• Polymerization & Reactivity: The molecule contains both a highly reactive carbon-carbon double bond and a nitrile group (-CN). It readily undergoes free-radical polymerization when exposed to heat, light, or initiators. Commercial products typically contain stabilizers/inhibitors to prevent premature self-polymerization during storage.
• Flammability & Thermal Decomposition: Highly flammable; exposure to open flames or high heat can cause combustion and release toxic gases. Under extreme fire conditions, it can undergo exothermic polymerization that may rupture containers.
• Incompatibility: Chemically incompatible with strong oxidizing agents, strong acids, strong bases, amines, and halogens (e.g., bromine). Contact with these substances can trigger violent or explosive reactions.
• Toxicity: Classified as a Class 1 carcinogen by the IARC. It is highly toxic if inhaled, ingested, or absorbed through the skin. Exposure can cause severe irritation, nausea, headaches, and long-term health effects.

Key Applications

• Synthetic Fibers (Acrylic): This is its largest application. Polymerized into polyacrylonitrile (PAN), it is spun into acrylic fibers widely used in textiles, carpets, and apparel due to their wool-like warmth, durability, and resistance to moths and chemicals.
• Engineering Plastics (ABS & SAN Resins): Copolymerized with styrene and butadiene to produce ABS resin, a tough, impact-resistant plastic extensively used in automotive parts, consumer electronics, appliances, and 3D printing.
• Carbon Fiber Precursor: PAN derived from acrylonitrile is the primary precursor for manufacturing carbon fiber, a lightweight, high-strength material critical for aerospace, wind energy, and high-performance automotive industries.
• Synthetic Rubbers: Copolymerized with butadiene to produce Nitrile Butadiene Rubber (NBR), which offers excellent resistance to oils, fuels, and chemicals, making it ideal for seals, gaskets, hoses, and protective gloves.
• Chemical Intermediates: Hydrolyzed to produce acrylamide and acrylic acid, which are vital monomers for water treatment flocculants, adhesives, and superabsorbent polymers. It is also used to synthesize pharmaceuticals, dyes, and agrochemicals.