| Azobisisobutyronitrile | |
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2,2′-Azobis(2-methylpropionitrile) |
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Other names
Azobisisobutyronitrile |
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| Identifiers | |
| Abbreviations | AIBN |
| CAS number | 78-67-1 |
| PubChem | 6547 |
| ChemSpider | 6299 |
| EC-number | 201-132-3 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C8H12N4 |
| Molar mass | 164.21 g/mol |
| Appearance | white crystalline |
| Density | 1.1 g cm−3 |
| Melting point |
103-105 °C, 376-378 K, 217-221 °F |
| Hazards | |
| R-phrases | R11, R25, R37/38, R41 |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Azobisisobutyronitrile is a compound often used as a foamer in plastics and rubber and as a radical initiator. It is commonly known as AIBN. Its most common chemical reaction is one of decomposition, eliminating a molecule of nitrogen gas to form two 2-cyanoprop-2-yl radicals:
These radicals can be used to initiate free radical polymerizations and other radical reactions. For instance a mixture of styrene and maleic anhydride in toluene will react if heated, forming the polystyrene polymer, only very slowly unless an initiator such an AIBN is present. Another example of a radical reaction that can be initiated by AIBN is the anti-Markovnikov hydrohalogenation of alkenes.
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AIBN is safer to use than benzoyl peroxide (another radical initiator) because the risk of explosion is far smaller. However, it is considered a flammable solid. It is soluble in methanol and ethanol, but is insoluble in water. It can explode if dissolved in acetone. AIBN is highly toxic. A respirator/dust mask, protective gloves, & safety glasses should be worn when handling AIBN.
Several water-soluble azo initiators similar to AIBN are manufactured by DuPont[1] and Wako.[2]