Azodicarbonamide

Azodicarbonamide
IUPAC name Carbamoyliminourea
Other names Azodicarboxamide; Azobisformamide; C,C'-Azodi(formamide); Diazenedicarboxamide
Identifiers
CAS number	123-77-3 Y
PubChem	31269
ChemSpider	4575589 Y
UNII	56Z28B9C8O Y
EC-number	204-650-8
ChEMBL	CHEMBL28517 Y
Jmol-3D images	Image 1
SMILES O=C(/N=N/C(=O)N)N
InChI InChI=1S/C2H4N4O2/c3-1(7)5-6-2(4)8/h(H2,3,7)(H2,4,8)/b6-5+ Y Key: XOZUGNYVDXMRKW-AATRIKPKSA-N Y InChI=1/C2H4N4O2/c3-1(7)5-6-2(4)8/h(H2,3,7)(H2,4,8)/b6-5+ Key: XOZUGNYVDXMRKW-AATRIKPKBW
Properties
Molecular formula	C2H4N4O2
Molar mass	116.08 g mol−1
Appearance	Yellow to orange/red crystalline powder
Hazards
MSDS	External MSDS
EU classification	Harmful (XN)
R-phrases	R42 R44
S-phrases	S22 S24 S37
NFPA 704	1 2 2
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Azodicarbonamide, or azobisformamide, is a synthetic chemical 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

Azodicarbonamide is used in food industry as a food additive, a flour bleaching agent and improving agent. It reacts with moist flour as an oxidizing agent.^[2] The main reaction product is biurea^[3] (not urea), which is stable during baking. Secondary reaction products include semicarbazide^[4] and ethyl carbamate.^[5]

The United States allows azodicarbonamide to be added to flour at levels up to 45 ppm.^[6]

Other uses

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.

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, but there are some products that the reaction temperature must be lower, depending on the application. 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.

Use of azodicarbonamide as a blowing agent in plastics is banned in Europe^[7].

Safety

In the UK, the Health and Safety Executive 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."^[8]

Azodicarbonamide may cause an allergic reaction in those sensitive to other azo compounds, such as food dyes.^{[medical citation needed]} The consumption of azodicarbonamide may also heighten an allergic reaction to other ingredients in a food.^{[medical citation needed]}

Toxicological studies of the reactions of azodicarbonamide show that it is rapidly converted to biurea in dough, which is a stable compound not decomposed upon cooking.^[9]

See also

• Semicarbazide

References