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Revision as of 08:27, 18 January 2011 editBeetstra (talk | contribs)Edit filter managers, Administrators172,294 edits Script assisted update of identifiers from ChemSpider, CommonChemistry and FDA for the Chem/Drugbox validation project - Updated: ChEMBL.← Previous edit Latest revision as of 15:49, 10 October 2024 edit undoFrost (talk | contribs)Extended confirmed users, Page movers, New page reviewers, Pending changes reviewers, Rollbackers56,573 edits Reverting edit(s) by 65.211.3.131 (talk) to rev. 1249149333 by Rkinch: Non-constructive edit (UV 0.1.6)Tags: Ultraviolet Undo 
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{{Use dmy dates|date=August 2023}}
{{chembox {{chembox
| Watchedfields = changed | Watchedfields = changed
| verifiedrevid = 396295055 | verifiedrevid = 408554140
| ImageFile = Azodicarbonamide.png | ImageFile = Azodicarbonamide.png
| ImageAlt = Skeletal formula of azodicarbonamide
| ImageSize =
| ImageFile1 = Azodicarbonamide 3D spacefill.png
| ImageAlt1 = Space-filling model of azodicarbonamide
| IUPACName = Carbamoyliminourea | IUPACName = Carbamoyliminourea
| OtherNames = Azodicarobxamide<br />Azobisformamide<br />C,C'-azodi(formamide) | OtherNames = {{Unbulleted list|Azodicarboxamide|Azobisformamide|C,C'-Azodi(formamide)|Diazenedicarboxamide}}
| Section1 = {{Chembox Identifiers |Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 4575589 | ChemSpiderID = 4575589
| UNII_Ref = {{fdacite|correct|FDA}} | UNII_Ref = {{fdacite|correct|FDA}}
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| InChI = 1/C2H4N4O2/c3-1(7)5-6-2(4)8/h(H2,3,7)(H2,4,8)/b6-5+ | InChI = 1/C2H4N4O2/c3-1(7)5-6-2(4)8/h(H2,3,7)(H2,4,8)/b6-5+
| InChIKey = XOZUGNYVDXMRKW-AATRIKPKBW | InChIKey = XOZUGNYVDXMRKW-AATRIKPKBW
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 28517 | ChEMBL = 28517
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI_Ref = {{stdinchicite|correct|chemspider}}
Line 20: Line 24:
| CASNo_Ref = {{cascite|correct|CAS}} | CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 123-77-3 | CASNo = 123-77-3
| EC-number = 204-650-8 | EC_number = 204-650-8
| PubChem = 31269 | PubChem = 31269
| SMILES = O=C(/N=N/C(=O)N)N | SMILES = O=C(/N=N/C(=O)N)N
}} }}
| Section2 = {{Chembox Properties |Section2={{Chembox Properties
| C=2|H=4|O=2|N=4 | C=2 | H=4 | O=2 | N=4
| Appearance = Yellow to orange/red crystalline powder | Appearance = Yellow to orange/red crystalline powder
| Density = | Density =
| MeltingPt = | MeltingPtC = 225
| MeltingPt_notes = (decomposes)
| BoilingPt =
| Solubility = | BoilingPt =
| Solubility =
}} }}
| Section3 = {{Chembox Hazards |Section3={{Chembox Hazards
| MainHazards = | MainHazards =
| FlashPt = | FlashPt =
| Autoignition = | AutoignitionPt =
| NFPA-H = 2 | NFPA-F = 1 | NFPA-R = 2 | NFPA-H = 1 | NFPA-F = 1 | NFPA-R = 0
| GHSPictograms = {{GHS08}}
| EUClass = Harmful ('''XN''')
| GHSSignalWord = Danger
| RPhrases = {{R42}} {{R44}}
| SPhrases = {{S22}} {{S24}} {{S37}} | HPhrases = {{H-phrases|242|331|334|}}
| PPhrases = {{P-phrases|}}
| ExternalMSDS =
| ExternalSDS =
}} }}
}} }}


'''Azodicarbonamide''', '''ADCA''', '''ACA''',<ref>{{Cite news |last=Farah |first=Troy |date=2019-05-28 |title=Banned bread: why does the US allow additives that Europe says are unsafe? |url=https://www.theguardian.com/us-news/2019/may/28/bread-additives-chemicals-us-toxic-america |access-date=2024-06-07 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> '''ADA,''' or '''azo(''bis'')formamide''', is a chemical compound with the molecular formula {{chem2|C2H4O2N4}}.<ref>{{Cite web|url=http://www.inchem.org/documents/cicads/cicads/cicad16.htm#PartNumber:2|title=Azodicarbonamide (CICADS)|publisher=]|work=Inchem|access-date=2010-08-14| archive-url= https://web.archive.org/web/20100824055553/http://www.inchem.org/documents/cicads/cicads/cicad16.htm| archive-date= 24 August 2010 | url-status= live}} Also published by ], Geneva, 1999.</ref> It is a yellow to orange-red, odorless, crystalline powder. It is sometimes called a 'yoga mat' chemical because of its widespread use in foamed plastics.<ref>{{cite journal |last1=Arts |first1=Josje |last2=Kimber |first2=Ian |title=Azodicarbonamide (ADCA): A reconsideration of classification as a respiratory sensitiser |journal=Regulatory Toxicology and Pharmacology |date=October 2017 |volume=89 |pages=268–278 |doi=10.1016/j.yrtph.2017.07.018 |pmid=28734852 |doi-access=free }}</ref><ref>{{Cite web | url=https://www.npr.org/sections/thesalt/2014/03/06/286886095/almost-500-foods-contain-the-yoga-mat-compound-should-we-care-keep |title = Almost 500 Foods Contain the 'Yoga Mat' Compound. Should We Care?| website=] }}</ref> It was first described by John Bryden in 1959.<ref>{{cite journal |last1=Bryden |first1=J. H. |title=The crystal structure of azodicarbonamide |journal=Acta Crystallographica |date=10 January 1961 |volume=14 |issue=1 |pages=61–63 |doi=10.1107/S0365110X61000139 |doi-access= |bibcode=1961AcCry..14...61B }}</ref>
'''Azodicarbonamide''', or '''azobisformamide''', is an synthetic chemical with the molecular formula C<sub>2</sub>H<sub>4</sub>O<sub>2</sub>N<sub>4</sub>.<ref>{{Cite web|url=http://www.inchem.org/documents/cicads/cicads/cicad16.htm#PartNumber:2|title=Azodicarbonamide (CICADS)|publisher=]|work=Inchem|accessdate=2010-08-14}}</ref> It is a yellow to orange red, odorless, crystalline powder. As a ], it is known by the ] '''E927'''.


==Synthesis==
⚫ ==Use as a food additive==
It is prepared in two steps via treatment of ] with ] to form ], as described in this idealized equation:
Azodicarbonamide is used in food industry as a ], a ] and ]. It reacts with moist flour as an oxidizing agent.<ref>{{Cite web|url=http://www.garudaint.com/product.php?id=86|title=Azodicarbonamide FCC Grade (98%)|date=2009-02-13|accessdate=2010-08-14|publisher=Garuda International, Inc.}}</ref> The main reaction product is biurea<ref>{{Cite journal|url=http://www.aaccnet.org/cerealchemistry/backissues/1963/Chem40_539.pdf|title=A New Powdered Agent for Flour Maturing|first=Robert|last=Joiner|first2=Frederick|DUPLICATE DATA: last=Vidal|first3=Henry|last3=Marks|year=1963|month=September|journal=Cereal Chemistry|volume=40|pages=539–553}}</ref> (not ]), which is stable during baking.
:{{chem2|2 O\dC(NH2)2 + H2N\sNH2 → H2N\sC(\dO)\sNH\sNH\sC(\dO)\sNH2 + 2 NH3}}
Secondary reaction products include ]<ref>{{Cite journal|title=Semicarbazide formation in azodicarbonamide-treated flour: a model study.|pmid=15373416|journal=Journal of agricultural and food chemistry|author=Becalski A, Lau BP, Lewis D, Seaman SW|volume=52|issue=18|date=2004-09-10|pages=5730–4|publisher=]|doi=10.1021/jf0495385}}</ref> and ].<ref>{{Cite journal|pmid=9059587|doi=10.1080/02652039709374501|doi_brokendate=2010-08-14|title=Ethyl carbamate levels resulting from azodicarbonamide use in bread|last1=Cañas|first1=BJ|last2=Diachenko|first2=GW|last3=Nyman|first3=PJ|journal=Food Additives & Contaminants|volume=14|issue=1|year=1997|month=January|pages=89–94}}</ref>


Oxidation with ] or ] yields azodicarbonamide:
The United States allows azodicarbonamide to be added to flour at levels up to 45 ].<ref>{{Cite web|url=http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=172&showFR=1&subpartNode=21:3.0.1.1.3.9|title=CFR - Code of Federal Regulations Title 21|date=2009-04-01|accessdate=2010-08-14|publisher=]}}</ref> Use of azodicarbonamide as a food additive is banned in Australia and in Europe. In Singapore, the use of azodicarbonamide can result in up to 15 years imprisonment and a fine of $450,000.{{Citation needed|date=June 2008}}
:{{chem2|H2N\sC(\dO)\sNH\sNH\sC(\dO)\sNH2 + Cl2 → H2N\sC(\dO)\sN\dN\sC(\dO)\sNH2 + 2 HCl}}


==Other uses== == Applications ==
===Blowing agent===
The principal use of azodicarbonamide is in the production of foamed plastics as an additive. 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. Common examples of this application are window and door gaskets, padded floor mats, gym/exercise mats, shoe soles, etc. The principal use of azodicarbonamide is in the production of foamed plastics as a ]. The thermal decomposition of azodicarbonamide produces nitrogen, carbon monoxide, carbon dioxide, and ammonia gases, which are trapped in the polymer as bubbles to form a foamed article.<ref name=Ull>{{cite encyclopedia|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry |author=Heinz Weber |author2=Isidoor De Grave |author3=Eckhard Röhrl |author4=Volker Altstädt |year=2016|pages= 1–54|doi=10.1002/14356007.a11_435.pub2|publisher=Wiley-VCH|chapter=Foamed Plastics|isbn= 978-3-527-30673-2}}</ref>


It is important to mention that azodicarbonamide in the use of 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 degrees C, but there are some products that the reaction temperature must be lower, depending on the application. In the plastic, leather and other industries, modified azodiarbonamide (average decomposition temperature 170 degrees C) contain additives that accelerate the reaction or react at lower temperatures. Azodicarbonamide is used in plastics, synthetic leather, and other industries and can be pure or modified. Modification affects the reaction temperatures. Pure azodicarbonamide generally reacts around 200&nbsp;°C. In the plastic, leather, and other industries, modified azodicarbonamide (average decomposition temperature 170&nbsp;°C) contains additives that accelerate the reaction or react at lower temperatures.<ref name=Ull/>


An example of the use of azodicarbonamide as a blowing agent is found in the manufacture of ] and ], where it forms bubbles upon breaking down into gas at high temperature. Vinyl foam is springy and does not slip on smooth surfaces. It is useful for ] and ]s. Commercial ]s made of vinyl foam have been available since the 1980s; the first mats were cut from carpet underlay.<ref>{{cite book | first=John | last=Friend | author-link=John Friend (yogi) | year=2009 | title=History of Yoga Mat - Looking back with Friends }}</ref>
==Safety==
In the UK, the ] has identified azodicarbonamide as a respiratory sensitizer (a possible cause of asthma) and determined that products should be labeled with "May cause sensitisation by inhalation."<ref>{{Cite web|url=http://www.ohsrep.org.au/index.cfm?section=10&Category=69&viewmode=content&contentid=62|title=Substances causing/worsening asthma|work=UK Occupational Health and Safety|publisher=]|accessdate=2010-08-14}}</ref>


⚫ ===Food additive===
Azodicarbonamide may cause an allergic reaction in those sensitive to other ]s, such as food dyes. The consumption of azodicarbonamide may also heighten an allergic reaction to other ingredients in a food.
As a ], azodicarbonamide is used as a ] and a ].<ref name="FDA">FDA Page Last Updated: 20 June 2014</ref> It reacts with moist flour as an oxidizing agent.<ref name="WHOFAO">WHO FAO 1965. Toxicological Evaluation of Some Antimicrobials, Antioxidants, Emulsifiers, Stabilizers, Flour-Treatment Agents, Acids and Bases: FAO Nutrition Meetings Report Series No. 40A,B,C. WHO/Food Add./67.29</ref> The main reaction product is ], which is stable during baking.<ref name="WHOFAO" /> Secondary reaction products include ] and ].<ref name="FDA" /> It is known by the ] '''E927'''. Many restaurants in the US fast food industry removed the additive in response to negative publicity.<ref name="bloomberg">{{Cite news|url=https://www.bloomberg.com/news/articles/2016-08-08/the-yoga-mat-chemical-s-quiet-fast-food-exit|title= The Yoga-Mat Chemical's Quiet Fast-Food Exit|access-date=2016-08-08|newspaper=]|date= 8 August 2016}}</ref>


==Safety and regulation==
In connection with food safety, it has wrongly been claimed that azodicarbonamide is completely decomposed into common substances during baking, either into urea or (alternatively) into gases (carbon dioxide, carbon monoxide, nitrogen, and ammonia). Toxicological studies of the reactions of azodicarbonamide show that it is rapidly converted to ] in dough, which is a stable compound not decomposed upon cooking.<ref>{{Cite web|url=http://www.inchem.org/documents/jecfa/jecmono/40abcj28.htm|title=054. Azodicarbonamide (FAO Nutrition Meetings Report Series 40abc)|work=]/]|date=1966-10-18|accessdate=2010-08-14}}</ref>


=== Occupational (inhalation) ===
==See also==
In a 1999 report, the ] has linked exposure to azodicarbonamide at workplaces where it is manufactured or handled in raw form to "respiratory issues, allergies and asthma". 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.<ref>{{Cite web|url=https://www.who.int/ipcs/publications/cicad/en/cicad16.pdf|title=Concise International Chemical Assessment Document 16: Azodicarbonamide|publisher=]|access-date=2014-02-05}}</ref> The WHO concluded, "The level of risk is uncertain; hence, exposure levels should be reduced as much as possible".
* ]

In the ], the ] has identified azodicarbonamide as a respiratory sensitizer (a possible cause of ]) in workplace settings and determined that containers of it should be labeled with "May cause sensitisation by inhalation."<ref>{{Cite web|url=http://www.ohsrep.org.au/index.cfm?section=10&Category=69&viewmode=content&contentid=62 |title=Substances causing/worsening asthma |work=UK Occupational Health and Safety |publisher=] |access-date=2010-08-14 |archive-url=https://web.archive.org/web/20130531062959/http://www.ohsrep.org.au/index.cfm?section=10&Category=69&viewmode=content&contentid=62 |archive-date=May 31, 2013 }}</ref> Azodicarbonamide was added to the ] candidate ] list in 2012, for its respiratory sensitizing properties.<ref>{{Cite web|url=https://echa.europa.eu/candidate-list-table?p_p_id=disslists_WAR_disslistsportlet&p_p_lifecycle=0&p_p_state=normal&p_p_mode=view&p_p_col_id=column-1&p_p_col_pos=2&p_p_col_count=3&_disslists_WAR_disslistsportlet_keywords=&_disslists_WAR_disslistsportlet_orderByCol=dte_inclusion&_disslists_WAR_disslistsportlet_advancedSearch=false&_disslists_WAR_disslistsportlet_casNumber=&_disslists_WAR_disslistsportlet_deltaParamValue=50&_disslists_WAR_disslistsportlet_andOperator=true&_disslists_WAR_disslistsportlet_haz_detailed_concern=&_disslists_WAR_disslistsportlet_name=&_disslists_WAR_disslistsportlet_orderByType=desc&_disslists_WAR_disslistsportlet_ecNumber=&_disslists_WAR_disslistsportlet_dte_inclusionFrom=&_disslists_WAR_disslistsportlet_dte_inclusionTo=&_disslists_WAR_disslistsportlet_doSearch=&_disslists_WAR_disslistsportlet_resetCur=false&_disslists_WAR_disslistsportlet_delta=200|title=Candidate List of substances of very high concern for Authorisation|website=ECHA|language=en-GB|access-date=2018-10-30 |quote=Diazene-1,2-dicarboxamide (C,C'-azodi(formamide)) (ADCA)... respiratory sensitising properties (Article 57(f) - human health)}}</ref>

=== Food (ingestion) ===
In some jurisdictions, the use of azodicarbonamide as a flour bleaching agent has been phased out. For example, it is no longer authorized for use in Australia and the ] as a food additive.<ref name="FADB">{{cite book|title=Food additives data book|last1=Smith|first1=Jim|last2=Hong-Shum|first2=Lily|publisher=Wiley-Blackwell|year=2011|isbn=978-1-4051-9543-0|edition=2nd|location=Chichester, West Sussex|page=548}}</ref><ref name="EU">{{cite web|title=European Union: Authorisation of Additives|url=https://webgate.ec.europa.eu/sanco_foods/main/|author=European Commission|access-date=2014-12-31|archive-url=https://web.archive.org/web/20141231123803/https://webgate.ec.europa.eu/sanco_foods/main/|archive-date=2014-12-31|author-link=European Commission}}</ref> Azodicarbonamide as a blowing agent in plastics has been banned in the European Union since August 2005 for the manufacture of plastic articles that are intended to come into direct contact with food.<ref name=EU05>{{Cite web|url=http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2004:007:0045:0046:EN:PDF|title=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|date=2004-01-13|access-date=2011-03-10|publisher=]}}</ref>
In the United States, azodicarbonamide has a ] (GRAS) status and is allowed to be added to flour at levels up to 45 ].<ref>{{cite journal|date=April 1, 2012|title=21CFR172.806|url=http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=172.806|journal=]}}</ref><ref name="FADB" /> However, use in products intended for human consumption is in decline under pressure of the public opinion.<ref name="bloomberg"/> In 2014, amid public discomfort with the dual uses of azodicarbonamide, the sandwich franchise ] and hamburger franchise ] announced that they would no longer use it as a dough conditioner.<ref name="CNN">{{cite news|url=http://www.cnn.com/2014/02/06/health/subway-bread-chemical/|title=Subway to remove 'dough conditioner' chemical from bread|date=February 17, 2014|agency=CNN|last1=Landau|first1=Elizabeth|access-date=3 November 2015}}</ref> As of February 2014, the ] stated azodicarbonamide "has been poorly tested" and advocates for reducing the amount of azodicarbonamide that is allowed to be used in food.<ref name="CNN" />

Banning ADA in food is motivated by studies of ], a side product of ADA use in packaging, showing "weak carcinogenic activity in laboratory
animals" but inconclusive as to carcinogenic risk to humans.<ref name=EU05/> The EU banned ADA in food containers despite an EFSA report considering such exposure "not a concern" due to low levels produced. The FDA considers ADA to be safe in permissible concentrations.<ref name="FDA" />

As of February, 2021, in contrast to direct competitors like Wendy's that have phased out the ingredient, ] continues to use azodicarbonamide in an unspecified quantity ("under 2 %") in their standard hamburger buns.<ref>awrestaurants.com {{Webarchive|url=https://web.archive.org/web/20220422053108/https://awrestaurants.com/sites/default/files/Ingredients%20-%20Core%20Supplemental%20Nutritionals%20-%20August%202018.pdf |date=22 April 2022 }}</ref>


==References== ==References==
{{reflist}} {{Reflist|30em}}

==External links==
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{{E number infobox 920-929}} {{E number infobox 920-929}}
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