2,2′-AZOBIS(2-METHYLPROPANENITRILE)

2,2′-Azobis(2-methylpropanenitrile) is a thermally unstable azo compound commonly abbreviated AIBN.
2,2′-Azobis(2-methylpropanenitrile) is used principally as a free-radical initiator in polymerization, grafting, curing, and controlled organic-synthesis processes.
2,2′-Azobis(2-methylpropanenitrile) is also used as a chemical blowing agent but requires strict temperature, ignition, contamination, static-electricity, and dust controls because heating can cause self-accelerating decomposition and fire.

CAS Number: 78-67-1
EC Number: 201-132-3
Molecular Formula: C8H12N4
Molecular Weight: 164.21 g/mol

Synonyms: 2,2′-Azobis(2-methylpropanenitrile), 2,2′-Azobis(2-methylpropionitrile), 2,2′-Azobis(isobutyronitrile), Azobisisobutyronitrile, AIBN, α,α′-Azobisisobutyronitrile, Alpha,alpha′-Azobisisobutyronitrile, α,α′-Azodiisobutyronitrile, Azodiisobutyronitrile, 2,2′-Azodiisobutyronitrile, 2,2′-Dimethyl-2,2′-azodipropionitrile, 2,2′-Dicyano-2,2′-azopropane, N,N′-Bis(2-cyano-2-propyl)diazene, Propanenitrile, 2,2′-azobis[2-methyl-, Propanenitrile, 2,2′-(1,2-diazenediyl)bis[2-methyl-, Azobis[isobutyronitrile], Azodi(isobutyronitrile), Azodiisobutyrodinitrile, Azodiisobutyric Acid Dinitrile, AZDN, AZDH, AIVN, V-60, Vazo 64, Vazo 64 Initiator, Perkadox AIBN, Porofor N, Porophor N, Porofor 57, Genitron, Genitron AZDN, Genitron AZDN-FF, Aceto AZIB, Pianofor AN, ChKhZ 57, Poly-Zole AZDN, Free-Radical Azo Initiator, Polymerization Initiator, Azo Blowing Agent, CAS 78-67-1, EC 201-132-3, PubChem CID 6547, UNII FZ6PX8U5YB, ChEBI 189360, UN 3234

APPLICATIONS

2,2′-Azobis(2-methylpropanenitrile) is used as a free-radical polymerization initiator.
2,2′-Azobis(2-methylpropanenitrile) is used to generate carbon-centered radicals through controlled thermal decomposition.
2,2′-Azobis(2-methylpropanenitrile) is used in batch, solution, suspension, emulsion, and bulk polymerization systems when technically suitable.
2,2′-Azobis(2-methylpropanenitrile) is used only within validated temperature and process-safety limits established for the complete reaction system.

2,2′-Azobis(2-methylpropanenitrile) is used in vinyl-monomer polymerization.
2,2′-Azobis(2-methylpropanenitrile) is used in the preparation of acrylic, methacrylic, styrenic, vinyl-acetate, and related polymers.
2,2′-Azobis(2-methylpropanenitrile) is used to initiate polymer-chain formation without introducing an inorganic initiator residue.
2,2′-Azobis(2-methylpropanenitrile) is used after monomer reactivity, solvent compatibility, heat removal, and runaway-reaction risks have been assessed.

2,2′-Azobis(2-methylpropanenitrile) is used in acrylic-resin manufacture.
2,2′-Azobis(2-methylpropanenitrile) is used in resins for coatings, adhesives, inks, sealants, and polymer modifiers.
2,2′-Azobis(2-methylpropanenitrile) is used to control polymer formation through the selected initiator concentration and feed strategy.
2,2′-Azobis(2-methylpropanenitrile) is used only through qualified process designs that prevent accumulation of unreacted initiator.

2,2′-Azobis(2-methylpropanenitrile) is used in styrene and styrenic-copolymer research.
2,2′-Azobis(2-methylpropanenitrile) is used in the preparation of selected polystyrene, acrylonitrile-containing, and functional styrenic materials.
2,2′-Azobis(2-methylpropanenitrile) is used in kinetic and molecular-weight-control studies.
2,2′-Azobis(2-methylpropanenitrile) is used after the hazards of every monomer, solvent, chain-transfer agent, and additive have been evaluated.

2,2′-Azobis(2-methylpropanenitrile) is used in controlled and living-radical polymerization research.
2,2′-Azobis(2-methylpropanenitrile) is used as a radical source in selected RAFT, nitroxide-mediated, and related polymerization systems.
2,2′-Azobis(2-methylpropanenitrile) is used in block-copolymer, graft-polymer, and functional-polymer development.
2,2′-Azobis(2-methylpropanenitrile) is used under research protocols that control oxygen, temperature, pressure, and reaction exotherm.

2,2′-Azobis(2-methylpropanenitrile) is used in polymer-grafting and surface-modification research.
2,2′-Azobis(2-methylpropanenitrile) is used to initiate radical attachment of compatible monomers onto polymers, particles, fibers, and surfaces.
2,2′-Azobis(2-methylpropanenitrile) is used in the preparation of functional membranes, hydrogels, coatings, and composite interfaces.
2,2′-Azobis(2-methylpropanenitrile) is used after residual initiator and decomposition-product limits have been established.

2,2′-Azobis(2-methylpropanenitrile) is used in curing selected unsaturated polyester-resin systems.
2,2′-Azobis(2-methylpropanenitrile) is used as a radical-generating component in suitably engineered thermosetting processes.
2,2′-Azobis(2-methylpropanenitrile) is used only when its decomposition characteristics match the intended curing cycle.
2,2′-Azobis(2-methylpropanenitrile) is used after cure exotherm, gel time, laminate thickness, and heat-transfer conditions have been evaluated.

2,2′-Azobis(2-methylpropanenitrile) is used as a chemical blowing agent for selected plastics and elastomers.
2,2′-Azobis(2-methylpropanenitrile) is used to release nitrogen gas during controlled thermal decomposition.
2,2′-Azobis(2-methylpropanenitrile) is used to form cellular structures in compatible polymer-processing systems.
2,2′-Azobis(2-methylpropanenitrile) is used only in industrial formulations designed to control decomposition rate, gas evolution, pressure, and residual by-products.

DESCRIPTION

2,2′-Azobis(2-methylpropanenitrile) is a symmetrical organic azo compound containing two nitrile groups.
2,2′-Azobis(2-methylpropanenitrile) has the molecular formula C8H12N4 and molecular weight 164.21 g/mol.
2,2′-Azobis(2-methylpropanenitrile) has CAS number 78-67-1 and EC number 201-132-3.
2,2′-Azobis(2-methylpropanenitrile) has the IUPAC name 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile.

2,2′-Azobis(2-methylpropanenitrile) is generally supplied as a white crystalline powder or solid.
2,2′-Azobis(2-methylpropanenitrile) has a representative density near 1.1 g/cm³ and is practically insoluble in water.
2,2′-Azobis(2-methylpropanenitrile) has vapor pressure below 1 Pa at 20°C, making dust more important than vapor during cold handling.
2,2′-Azobis(2-methylpropanenitrile) has a reported fusion temperature near 378 K, although hazardous decomposition behavior limits ordinary thermal processing.

2,2′-Azobis(2-methylpropanenitrile) decomposes to form nitrogen and reactive 2-cyano-2-propyl radicals.
2,2′-Azobis(2-methylpropanenitrile) can also generate toxic decomposition products including tetramethylsuccinonitrile and cyanide-containing fumes.
2,2′-Azobis(2-methylpropanenitrile) may decompose violently after heating, shock, friction, contamination, or incompatible chemical contact.
2,2′-Azobis(2-methylpropanenitrile) dry powder can acquire electrostatic charge and form explosive dust mixtures in air.

2,2′-Azobis(2-methylpropanenitrile) is classified as a Type C self-reactive chemical.
2,2′-Azobis(2-methylpropanenitrile) is classified as harmful if swallowed and harmful if inhaled.
2,2′-Azobis(2-methylpropanenitrile) is classified as harmful to aquatic life with long-lasting effects.
2,2′-Azobis(2-methylpropanenitrile) must be handled according to the exact supplier SDS because solutions, stabilized grades, and pure powder have different hazards and transport requirements.

PROPERTIES

Chemical Name: 2,2′-Azobis(2-methylpropanenitrile)
Common Name: Azobisisobutyronitrile
Common Abbreviation: AIBN
Alternative Abbreviation: AZDN
IUPAC Name: 2-(2-Cyanopropan-2-yldiazenyl)-2-methylpropanenitrile
Chemical Family: Aliphatic azo compounds
Functional Class: Free-radical initiator and chemical blowing agent
CAS Number: 78-67-1
EC Number: 201-132-3
European Index Number: 608-019-00-1
PubChem CID: 6547
UNII: FZ6PX8U5YB
ChEBI Identifier: CHEBI:189360
InChIKey: OZAIFHULBGXAKX-UHFFFAOYSA-N
Molecular Formula: C8H12N4
Condensed Formula: (CH3)2(CN)C–N=N–C(CN)(CH3)2
Molecular Weight: 164.21 g/mol
Physical State: Solid
Typical Appearance: White crystalline powder or crystals
Odor: Generally faint or not strongly characteristic
Representative Density: Approximately 1.1 g/cm³
Representative Fusion Temperature: Approximately 378 K or 105°C
Thermal Behavior: Decomposes on warming
Boiling Point: Not applicable because hazardous decomposition occurs
Water Solubility: Practically insoluble
Vapor Pressure: Less than 1 Pa at 20°C
Volatility: Very low at room temperature
Primary Airborne Hazard: Dust and decomposition products
Reported Autoignition Temperature: Approximately 64°C in the cited ICSC
Primary Decomposition Gas: Nitrogen
Other Decomposition Products: Tetramethylsuccinonitrile, cyanide-containing fumes, nitrogen oxides, carbon monoxide, and carbon dioxide
Primary Industrial Function: Free-radical polymerization initiator
Secondary Industrial Function: Chemical blowing agent
Other Functions: Thermoset-curing initiator and laboratory radical source
GHS Self-Reactive Classification: Type C
GHS Acute Oral Toxicity: Category 4
GHS Acute Inhalation Toxicity: Category 4
GHS Aquatic Classification: Aquatic Chronic Category 3
Hazard Statements: H242, H302, H332, and H412
Signal Word: Danger
Dust Hazard: Finely dispersed particles can form explosive mixtures in air
Electrostatic Hazard: Dry material can accumulate electrostatic charge
Incompatible Materials: Strong oxidizers and other substances identified by the product-specific SDS
Additional Reactive Hazards: Hazardous reactions have been reported with certain alcohols, ketones, aldehydes, and hydrocarbons
Representative UN Number: UN 3234
Representative Transport Class: Class 4.1
Transport Status: Product form, concentration, packaging, and temperature-control requirements dependent
Storage Requirement: Cool, fire-resistant, secure storage under supplier-specified temperature controls
Environmental Precaution: Prevent entry into drains, soil, and surface water
Shelf Life: Highly dependent on storage temperature, purity, packaging, and manufacturer
Regulatory Suitability: Grade, physical form, use, transport route, and jurisdiction dependent

Identity and physical-property data are supported by NIST and the ILO-WHO International Chemical Safety Card; current product classification is confirmed by the 2026 supplier SDS.

FIRST AID

Inhalation:
Move the affected person to fresh air without exposing rescuers to dust, smoke, or decomposition products.
Keep the person at rest and contact a physician promptly.
Provide respiratory support through trained personnel if breathing is impaired.

Skin Contact:
Immediately remove contaminated clothing.
Rinse the affected skin thoroughly with water or shower.
Obtain medical advice after substantial contact or if irritation develops.

Eye Contact:
Immediately rinse cautiously with clean water for at least 15 minutes.
Remove contact lenses if readily possible without delaying irrigation.
Obtain prompt medical evaluation.

Ingestion:
Rinse the mouth.
Do not induce vomiting unless specifically instructed by a poison center or medical professional.
Contact a physician or poison center immediately because ingestion can produce headache, nausea, weakness, convulsions, and systemic toxicity.

Note to Physicians:
Treat symptomatically and provide supportive care.
Monitor neurological, hepatic, renal, respiratory, and cardiovascular status after significant exposure.
Consider possible exposure to nitrile and cyanide-containing decomposition products.

HANDLING AND STORAGE

Handling:
Restrict handling to trained personnel familiar with self-reactive chemicals.
Avoid heat, shock, friction, sparks, flames, contamination, and uncontrolled mechanical handling.
Do not grind, crush, mill, scrape, or rapidly transfer dry material.

Temperature Control:
Maintain the storage and processing temperatures stated in the exact supplier SDS.
Do not rely on a generic temperature because control and emergency temperatures vary with purity, package size, solvent, and product form.
Use alarms and independent safeguards where temperature-control failure could cause self-heating.

Engineering Controls:
Use closed or contained transfer systems wherever practical.
Provide effective local exhaust at weighing, charging, and sampling points.
Use explosion-resistant equipment suitable for combustible and self-reactive dust.

Static and Dust Control:
Ground and bond equipment to prevent electrostatic accumulation.
Prevent deposition of powder on floors, ducts, beams, motors, and other surfaces.
Do not use compressed air or uncontrolled dry sweeping for cleaning.

Personal Protection:
Wear suitable chemical-resistant gloves, protective clothing, and chemical safety goggles.
Use face protection when dust dispersion or splashing from a solution is possible.
Use suitable respiratory protection when engineering controls cannot adequately prevent airborne exposure.

Storage:
Store in the original approved container in a cool, secure, fire-resistant, and well-ventilated area.
Keep the container tightly closed and protected from sunlight and external heating.
Segregate the material from incompatible substances and combustible contamination.

Fire:
Evacuate personnel from the threatened area and contact emergency services.
Do not approach heated, smoking, bulging, or damaged containers.
Fire response must account for self-accelerating decomposition and toxic cyanide- and nitrogen-containing fumes.

Spill:
Remove ignition and heat sources without approaching an unstable container.
Prevent dust dispersion, friction, impact, and static discharge.
Do not clean up a significant spill without supervision from a qualified hazardous-material specialist.

Solutions:
Do not assume that dissolving 2,2′-Azobis(2-methylpropanenitrile) eliminates the fire or decomposition hazard.
Do not concentrate, evaporate, or recover an AIBN solution without a validated process-safety assessment.
Apply the solvent’s flammability, toxicity, and transport controls in addition to the AIBN precautions.

Disposal:
Do not place unused material in ordinary laboratory or industrial waste.
Do not attempt uncontrolled heating, burning, neutralization, or solvent evaporation.
Use an authorized hazardous-waste contractor familiar with self-reactive azo initiators.

Handling Precautions:
Use the exact product SDS, certificate of analysis, expiry or retest date, and transport classification.
Do not use material that has been overheated, contaminated, improperly stored, or kept beyond the supplier’s approved period without specialist assessment.