|Jmol-3D images||Image 1|
|Molar mass||116.08 g mol−1|
|Appearance||Yellow to orange/red crystalline powder|
|Melting point||225 °C (decomposes)|
|EU classification||Harmful (XN)|
|S-phrases||S22 S24 S37|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Azodicarbonamide, or azo(bis)formamide, is a chemical compound with the molecular formula C2H4O2N4. It is a yellow to orange red, odorless, crystalline powder. As a food additive, it is known by the E number E927.
Use as a food additive
As a food additive, azodicarbonamide is used as a flour bleaching agent and an improving agent. It reacts with moist flour as an oxidizing agent. The main reaction product is biurea, a derivative of urea, which is stable during baking. Secondary reaction products include semicarbazide and ethyl carbamate. The United States and Canada permit the use of azodicarbonamide at levels up to 45 ppm. In Australia and Europe the use of azodicarbonamide as a food additive is banned. In South Korea, its use is allowed to the same amount as US and Canada but all flour manufacturers have voluntarily agreed to strictly ban the use of not just Azodicarbonamide but any bleaching agent since 1992.
The principal use of azodicarbonamide is in the production of foamed plastics as a blowing agent. The thermal decomposition of azodicarbonamide results in the evolution of nitrogen, carbon monoxide, carbon dioxide, and ammonia gases, which are trapped in the polymer as bubbles to form a foamed article.
Azodicarbonamide as used in plastics, synthetic leather and other uses can be pure or modified. This is important because modification affects the reaction temperatures. Pure azodicarbonamide generally reacts around 200 °C. In the plastic, leather and other industries, modified azodicarbonamide (average decomposition temperature 170 °C) contains additives that accelerate the reaction or react at lower temperatures.
In the UK, the Health and Safety Executive has identified azodicarbonamide as a respiratory sensitizer (a possible cause of asthma) in workplace settings and determined that containers of it should be labeled with "May cause sensitisation by inhalation." The World Health Organization has linked azodicarbonamide to "respiratory issues, allergies and asthma" for individuals at workplaces where azodicarbonamide is manufactured or handled in raw form. The available data are restricted to these occupational environments. Exposure of the general public to azodicarbonamide could not be evaluated because of the lack of available data.
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- Becalski A, Lau BP, Lewis D, Seaman SW (2004-09-10). "Semicarbazide formation in azodicarbonamide-treated flour: a model study". Journal of Agricultural and Food Chemistry (Journal of Agricultural and Food Chemistry) 52 (18): 5730–4. doi:10.1021/jf0495385. PMID 15373416.
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- "21CFR172.806". Code of Federal Regulations. April 1, 2012.
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- "COMMISSION DIRECTIVE 2004/1/EC of 6 January 2004 amending Directive 2002/72/EC as regards the suspension of the use of azodicarbonamide as blowing agent". Official Journal of the European Union. 2004-01-13. Retrieved 2011-03-10.
- "CFR - Code of Federal Regulations Title 21". United States Department of Health and Human Services. 2009-04-01. Retrieved 2010-08-14.
- "Substances causing/worsening asthma". UK Occupational Health and Safety. WorkSafe Victoria. Retrieved 2010-08-14.
- "Concise International Chemical Assessment Document 16: Azodicarbonamide". World Health Organization. Retrieved 2014-02-05.