2,2'-Azobis(2-methylpropionitrile)

Description

2,2''-Azobis(isobutyronitrile), or AIBN, is a commonly used initiator for free-radical reactions, including many polymerizations. Its preparation was first reported by Thiele and Heuser in 1896, and it has been used in polymerization since at least the 1940s. Its downsides are high toxicity (it decomposes to HCN in vivo), flammability, and the explosivity of its acetone solutions.

Description

Azobisisobutylonitrile is a white crystallinecompound. Molecular weight= 164.21; Specific gravity(H2O:1)= 1.11 at 25℃; Boiling point= decomposes;Freezing/Melting point= 99°103℃ (decomposes);Autoignition temperature= 63℃. NFPA 704 M HazardIdentification (based on NFPA-704M Rating System):Health 3, Flammability 2, Reactivity 2. Insoluble in water.

Chemical properties

Azobisisobutylonitrile is a white crystalline compound.

The Uses of 2,2'-Azobis(2-methylpropionitrile)

2,2'-Azobis(2-methylpropionitrile) (AIBN) is a foaming agent and inhibitor in plastic and elastomer materials. It is a radical initiator. AIBN solution can be used to initiate radical-induced reactions, specifically free-radical polymerizations. It can be used in:
Synthesis of styrene-vinyl pyridine diblock copolymers by reversible addition-fragmentation chain transfer (RAFT) polymerization.
Preparation of silicon oxycarbide glasses.
Synthesis of poly [N-(p-vinyl benzyl) phthalimide] for preparing titanium dioxide composites for electrophoretic displays.
Used as an initiator in synthesising highly cross-linked Poly(divinylbenzene) (PDVB) polymers.
Used as an initiator in the polymerization process of 2-hydroxyethyl methacrylate (HEMA).

Definition

ChEBI: (E)-Azobis(isobutyronitrile) is an azo compound.

General Description

Insoluble in water and denser than water. Moderately toxic by ingestion. Readily ignited by sparks or flames. Burns intensely and persistently. Toxic oxides of nitrogen produced during combustion. Used as a catalyst, in vinyl polymerizations and a blowing agent for plastics.

Air & Water Reactions

Dust may form an explosive mixture in air. Insoluble in water.

Reactivity Profile

Self-decomposition or self-ignition may be triggered by heat, chemical reaction, friction or impact. Self-accelerating decomposition may occur if the specific control temperature is not maintained. These materials are particularly sensitive to temperature rises. 2,2'-Azobis(2-methylpropionitrile) is an azo compound. Azo, diazo, azido compounds can detonate. This applies in particular to organic azides that have been sensitized by the addition of metal salts or strong acids. Toxic gases are formed by mixing materials of this class with acids, aldehydes, amides, carbamates, cyanides, inorganic fluorides, halogenated organics, isocyanates, ketones, metals, nitrides, peroxides, phenols, epoxides, acyl halides, and strong oxidizing or reducing agents. Flammable gases are formed by mixing materials in this group with alkali metals. Explosive combination can occur with strong oxidizing agents, metal salts, peroxides, and sulfides.

Hazard

Toxic by ingestion.

Flammability and Explosibility

Not classified

Safety Profile

Poison by intraperitoneal route. Moderately toxic by ingestion. Easily oxidized, unstable. Violent exothermic decomposition when heated. Solution in acetone may decompose explosively. Explodes when heated with heptane. When heated to decomposition it emits toxic fumes of NO, and CN-. See also NITRILES. A free-radcal generator.

Potential Exposure

Azobisisobutylonitrile is both a nitrile and azo compound. Used as a polymerization initiator, free radical generator (or initiator); as a catalyst in vinyl polymerizations; as a blowing agent for elastomers and plastics.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Note: Use amyl nitrate capsules if symptoms develop. Allarea employees should be trained regularly in emergencymeasures for cyanide poisoning and in CPR. A cyanide antidote kit should be kept in the immediate work area and mustbe rapidly available. Kit ingredients should be replaced every1°2 years to ensure freshness. Persons trained in the use ofthis kit, oxygen use, and CPR must be quickly available.

storage

Color Code—Red Stripe: Flammability Hazard: Donot store in the same area as other flammable materials. Priorto working with this chemical you should be trained on itsproper handling and storage. Azodiisobutyronitrile must bestored to avoid contact with acetone, lithium, aluminumhydride, and water, since violent reactions occur. Azodiisobutyronitrile is self-reactive and will explode at elevated temperatures. It should be stored under nitrogen, dry ice, or ice.Sources of ignition, such as smoking and open flames, areprohibited where this chemical is used, handled, or stored in amanner that could create a potential fire or explosion hazard.

Shipping

UN3234 Self-reactive solid type C, temperature controlled materials, Hazard Class: 4.1; Labels: 4.1- Flammable solid, Technical Name Required.

Incompatibilities

Flammable; dust may form explosive mixture with air. Unstable and easily oxidized material; keep away from oxidizers, strong acids. Keep at temperature not ≧30° C (this may vary by manufacturer). Risk of explosion from heat, shock, friction. Warming causes production of tetramethylsuccinonitrile and cyanide fumes. Keep away from acetone and other ketones, alcohols, lithium, aluminum, aldehydes, and hydrocarbons, such as heptane. Azo compounds can detonate. This applies in particular to organic azides that have been sensitized by the addition of metal salts or strong acids. Toxic gases are formed by mixing materials of this class with acids, aldehydes, amides, carbamates, cyanides, inorganic fluorides, halogenated organics, isocyanates, ketones, metals, nitrides, peroxides, phenols, epoxides, acyl halides, and strong oxidizing or reducing agents. Flammable gases are formed by mixing materials in this group with alkali metals. Explosive combination can occur with strong oxidizing agents, metal salts, peroxides, and sulfides. This chemical is sensitive to prolonged exposure to heat. This chemical is incompatible with strong oxidizing agents.