Azodicarbonamide

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Azodicarbonamide
Azodicarbonamide.png
Identifiers
CAS number 123-77-3 YesY
PubChem 31269
ChemSpider 4575589 YesY
UNII 56Z28B9C8O YesY
EC-number 204-650-8
ChEMBL CHEMBL28517 YesY
Jmol-3D images Image 1
Properties
Molecular formula C2H4N4O2
Molar mass 116.08 g mol−1
Appearance Yellow to orange/red crystalline powder
Hazards
MSDS [1]
EU classification Harmful (XN)
R-phrases R42 R44
S-phrases S22 S24 S37
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Azodicarbonamide, or azobisformamide, is a chemical compound with the molecular formula C2H4O2N4.[1] 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[edit]

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.[2] The main reaction product is biurea,[3] a derivative of urea, which is stable during baking. Secondary reaction products include semicarbazide[4] and ethyl carbamate.[5] The United States and Canada permit the use of azodicarbonamide at levels up to 45 ppm.[6][7] In Australia and Europe the use of azodicarbonamide as a food additive is banned.[8]

Other uses[edit]

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.

Azodicarbonamide as a blowing agent in plastics has been banned in Europe since August 2005 for the manufacture of plastic articles that are intended to come into direct contact with food.[9]

Safety[edit]

In the United States, azodicarbonamide has generally recognized as safe (GRAS) status and is allowed to be added to flour at levels up to 45 ppm.[10]

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."[11] 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.[12]

References[edit]

  1. ^ "Azodicarbonamide (CICADS)". Inchem. International Programme on Chemical Safety. Archived from the original on 24 August 2010. Retrieved 2010-08-14.  Also published by World Health Organization, Geneva, 1999.
  2. ^ "Azodicarbonamide FCC Grade (98%)". Garuda International, Inc. 2009-02-13. Retrieved 2010-08-14. 
  3. ^ Joiner, Robert; Vidal, Frederick; Marks, Henry (September 1963). "A New Powdered Agent for Flour Maturing". Cereal Chemistry 40: 539–553. 
  4. ^ 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. 
  5. ^ Cañas, BJ; Diachenko, GW; Nyman, PJ (January 1997). "Ethyl carbamate levels resulting from azodicarbonamide use in bread". Food Additives & Contaminants 14 (1): 89–94. doi:10.1080/02652039709374501. PMID 9059587. 
  6. ^ "21CFR172.806". Code of Federal Regulations. April 1, 2012. 
  7. ^ Hong-Shum, edited by Jim Smith, Lily (2011). Food additives data book (2nd ed.). Chichester, West Sussex: Wiley-Blackwell. p. 548. ISBN 978-1405195430. 
  8. ^ Smith, Jim (2011-06-20). Food Additives Databook. Wiley-Blackwell. p. 548. ISBN 978-1405195430. 
  9. ^ "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. 
  10. ^ "CFR - Code of Federal Regulations Title 21". United States Department of Health and Human Services. 2009-04-01. Retrieved 2010-08-14. 
  11. ^ "Substances causing/worsening asthma". UK Occupational Health and Safety. WorkSafe Victoria. Retrieved 2010-08-14. 
  12. ^ "Concise International Chemical Assessment Document 16: Azodicarbonamide". World Health Organization. Retrieved 2014-02-05. 

External links[edit]