22azobis2methylpropionitrile

2,2'-Azobis(2-methylpropionitrile), often abbreviated as AIBN, is an organic compound with the chemical formula C6H12N4. It is a white crystalline solid that is soluble in many organic solvents but poorly soluble in water. AIBN is primarily known for its role as a radical initiator in polymerization reactions.

When heated, AIBN decomposes to produce nitrogen gas and two carbon-centered radicals. These radicals are relatively stable due to resonance and can then initiate the polymerization of monomers such as styrene, acrylates, and methacrylates. The decomposition rate of AIBN is temperature-dependent, allowing for controlled polymerization by adjusting the reaction temperature. This controlled decomposition makes AIBN a popular choice for free radical polymerization, especially when a predictable initiation rate is desired.

The decomposition temperature range for AIBN is typically between 60°C and 80°C. At 65°C, the half-life of AIBN is approximately 10 hours, and at 80°C, it is about 1 hour. This predictable behavior allows chemists to select a decomposition rate suitable for their specific polymerization needs. Due to the nitrogen gas evolved during decomposition, reactions involving AIBN should be conducted in well-ventilated areas or under conditions that can safely handle gas evolution. AIBN is also sensitive to light and should be stored in a dark, cool place.