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{{chembox |
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{{chembox |
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| verifiedrevid = 396294932 |
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|verifiedrevid = 446117924 |
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|ImageFile_Ref = {{chemboximage|correct|??}} |
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| Name = |
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|ImageFile = AIBN Structural Formulae.svg |
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| ImageFile_Ref = {{chemboximage|correct|??}} |
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|ImageSize = 200px |
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| ImageFile = AIBN Structural Formulae.png |
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| ImageName = The chemical structure of AIBN |
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|ImageName = The chemical structure of AIBN |
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| ImageFile1 = AIBN-3D-vdW.png |
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|ImageFile1 = AIBN-3D-vdW.png |
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| ImageName1 = 3D model of the AIBN molecule |
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|ImageName1 = 3D model of the AIBN molecule |
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| IUPACName = 2,2′-Azobis(2-methylpropionitrile) |
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|IUPACName = 2,2′-Azobis(2-methylpropionitrile), 2-(azo(1-cyano-1-methylethyl))-2-methylpropane nitrile |
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| OtherNames = Azobisisobutyronitrile<br />Azobisisobutylonitrile<br />AIBN |
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|OtherNames = Azobisisobutyronitrile<br />Azobisisobutylonitrile<br />AIBN |
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| Section1 = {{Chembox Identifiers |
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|Section1={{Chembox Identifiers |
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| Abbreviations = AIBN |
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|Abbreviations = AIBN |
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| InChI = 1/C8H12N4/c1-7(2,5-9)11-12-8(3,4)6-10/h1-4H3/b12-11+ |
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|InChI = 1/C8H12N4/c1-7(2,5-9)11-12-8(3,4)6-10/h1-4H3/b12-11+ |
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| PubChem = 6547 |
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|PubChem = 6547 |
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|RTECS = UG0800000 |
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| InChIKey = OZAIFHULBGXAKX-VAWYXSNFBT |
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|UNNumber = 3234 1325 |
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| StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
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|UNII = FZ6PX8U5YB |
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| StdInChI = 1S/C8H12N4/c1-7(2,5-9)11-12-8(3,4)6-10/h1-4H3/b12-11+ |
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|InChIKey = OZAIFHULBGXAKX-VAWYXSNFBT |
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| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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|StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChIKey = OZAIFHULBGXAKX-VAWYXSNFSA-N |
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|StdInChI = 1S/C8H12N4/c1-7(2,5-9)11-12-8(3,4)6-10/h1-4H3/b12-11+ |
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| CASNo = 78-67-1 |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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|StdInChIKey = OZAIFHULBGXAKX-VAWYXSNFSA-N |
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| EC-number = 201-132-3 |
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|CASNo = 78-67-1 |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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|CASNo_Ref = {{cascite|correct|CAS}} |
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| ChemSpiderID = 6299 |
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|EC_number = 201-132-3 |
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| SMILES = CC(C)(C#N)/N=N/C(C)(C)C#N |
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|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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|ChemSpiderID = 6299 |
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|SMILES = CC(C)(C#N)/N=N/C(C)(C)C#N |
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|Section2={{Chembox Properties |
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|Formula = {{chem2|C8H12N4}} |
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|MolarMass = 164.21 g/mol |
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|Appearance = white crystals |
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|Density = 1.1 g cm<sup>−3</sup> |
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|Solubility = poor |
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|MeltingPtC = 103 to 105 |
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|Section7={{Chembox Hazards |
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|GHSPictograms = {{GHS02}}{{GHS07}} |
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|GHSSignalWord = Warning |
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|HPhrases = {{H-phrases|242|302|332|412}} |
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|PPhrases = {{P-phrases|210|220|234|261|264|270|271|273|280|301+312|304+312|304+340|312|330|370+378|403+235|411|420|501}} |
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}} |
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| Section2 = {{Chembox Properties |
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| Formula = C<sub>8</sub>H<sub>12</sub>N<sub>4</sub> |
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| MolarMass = 164.21 g/mol |
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| Appearance = white crystalline |
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| Density = 1.1 g cm<sup>−3</sup> |
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| Solubility = |
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| MeltingPtCL = 103 |
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| MeltingPtCH = 105 |
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| Section3 = {{Chembox Structure |
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| Dipole = |
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| Section7 = {{Chembox Hazards |
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| RPhrases = {{R11}}, {{R25}}, {{R37/38}}, {{R41}} |
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| FlashPt = |
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'''Azobisisobutyronitrile''' (abbreviated '''AIBN'''<ref>{{Cite book |last=Höfer |first=Rainer |title=Renewable Resources for Surface Coatings, Inks, and Adhesives |date=2022-11-11 |publisher=The Royal Society of Chemistry |isbn=978-1-78262-993-1 |language=en |doi=10.1039/9781788013024-fp015}}</ref>) is an ] with the ] {{chem2|2N2}}. This white powder is soluble in alcohols and common organic solvents but is insoluble in water. It is often used as a foamer in ] and ] and as a ]. |
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'''Azobisisobutyronitrile''' is a compound often used as a foamer in ] and ] and as a ]. It is commonly known as '''AIBN'''. Its most common chemical reaction is one of ], eliminating a molecule of ] gas to form two 2-cyanoprop-2-yl radicals: |
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As an azo initiator, radicals resulting from AIBN have multiple benefits<ref>AIBN initiator and other azo initiators. (n.d.). Retrieved from https://polymerchemistry.nouryon.com/products-applications/acrylic-polymer-initiators/aibn/</ref> over common ]s. For example, they do not have oxygenated byproducts or much yellow discoloration. Additionally, they do not cause too much grafting and therefore are often used when making adhesives, acrylic fibers, detergents, etc. |
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==Mechanism of decomposition== |
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These radicals can be used to initiate ]s and other radical reactions. For instance a mixture of ] and ] in ] will react if heated, forming the ] ], 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 ] hydrohalogenation of alkenes. |
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In its most characteristic reaction, AIBN ], eliminating a molecule of ] gas to form two 2-cyanoprop-2-yl radicals:] |
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Because azobisisobutyronitrile readily gives off free radicals, it is often used as a ]. This happens at temperatures above 40 °C,<ref>2,2′-Azobis(2-methylpropionitrile) 441090. (n.d.). Retrieved from https://www.sigmaaldrich.com/catalog/product/aldrich/441090?lang=en®ion=US</ref> but in experiments is more commonly done at temperatures between 66 °C and 72 °C.<ref name="ClaydenMTM">Clayden, J., Greeves, N., & Warren, S. (2017). Organic chemistry. MTM.</ref> This decomposition has a Δ''G''<sup>‡</sup> of 131 kJ/mol<ref name="ClaydenMTM"/> and results in two 2-cyano-2-propyl (carbon) radicals and a molecule of nitrogen gas. The release of nitrogen gas pushes this decomposition forward due to the increase in ]. And the 2-cyano-2-propyl radical is stabilized by the −CN group. |
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==Safety== |
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AIBN is safer to use than ] (another ]) because the risk of explosion is far smaller. However, it is considered a flammable solid. |
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It is soluble in methanol and ethanol, but is insoluble in water. It can explode if dissolved in acetone. |
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AIBN is highly toxic. A respirator/dust mask, protective gloves, & safety glasses should be worn when handling AIBN. |
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== Chemical reactions == |
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Several water-soluble azo initiators similar to AIBN are manufactured by ]<ref></ref> and Wako.<ref></ref> |
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These radicals formed by the decomposition of AIBN can initiate ]s and other radical-induced reactions. For instance, a mixture of ] and ] in ] will react if heated, forming the ] upon addition of AIBN. Another example of a radical reaction that can be initiated by AIBN is the ] hydrohalogenation of alkenes. AIBN has also been used as the radical initiator for ]. The AIBN-derived 2-cyano-2-propyl radical abstracts the hydrogen from ].<ref>{{cite journal |doi=10.15227/orgsyn.069.0066 |title=1,3,4,6-TETRA-O-ACETYL-2-DEOXY-a-D-GLUCOPYRANOSE |journal=Organic Syntheses |year=1990 |volume=69 |page=66|first1=Bernd|last1=Giese|first2=Kay S.|last2=Gröninger }}</ref> The resulting tributyltin radical can be used for removal of a bromine atom. |
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AIBN-derived radicals abstract a hydrogen from HBr to give a bromine radical, which can add to ]s. This type of ] of an alkene proceeds with anti-Markovnikov selectivity. |
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==See also== |
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:] |
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* 1,1'-Azobis(cyclohexanecarbonitrile) or ] is another free radical initiator |
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==Production and analogues== |
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AIBN is produced in two steps from ]. Reaction with ] gives the substituted dialkylhydrazine. In the second step, the hydrazine is oxidized to the azo derivative:<ref name=Ullmann>{{Ullmann|first1=Jean-Pierre |last1=Schirmann |first2=Paul |last2=Bourdauducq |title=Hydrazine |doi=10.1002/14356007.a13_177}}</ref><ref>Overberger, C. G., O'Shaughnessy, M. T., Shalit, H. (1949). The Preparation of Some Aliphatic Azo Nitriles and their Decomposition in Solution. Journal of the American Chemical Society, 71(8), 2661-2666. doi:10.1021/ja01176a018</ref> |
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:{{chem2|2 (CH3)2C(CN)OH + N2H4 -> 2N2H2 + 2 H2O}} |
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:{{chem2|2N2H2 + Cl2 -> 2N2 + 2 HCl}} |
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Related ]s behave similarly, such as ]. Water-soluble azo initiators are also available.<ref>{{cite web|title=Vazo Product Grades|url=http://www2.dupont.com/Vazo/en_US/products/grades/grades.html|website=www2.dupont.com|access-date=2007-12-15|archive-date=2009-03-26|archive-url=https://web.archive.org/web/20090326071213/http://www2.dupont.com/Vazo/en_US/products/grades/grades.html|url-status=dead}}</ref><ref></ref> |
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==Safety== |
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AIBN is safer to use than ] (another ]) because the risk of explosion is far less. However, it is still considered as an explosive compound, decomposing above 65 °C. A respirator dust mask, protective gloves and safety glasses are recommended. Pyrolysis of AIBN without a trap for the formed 2-cyanopropyl radicals results in the formation of ], which is highly toxic. |
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==References== |
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==References== |
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==External links== |
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==External links== |
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*{{SIDS|name=2,2’-Azobis(2-methylpropionitrile)|id =78671}} |
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*{{SIDS|name=2,2′-Azobis(2-methylpropionitrile)|id =78671}} |
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