Methyl yellow

Methyl yellow
Names
Preferred IUPAC name
N,N-Dimethyl-4-(phenyldiazenyl)aniline
Other names
4-Dimethylaminoazobenzene
p-Dimethylaminoazobenzene
DAB
N,N-Dimethyl-4-phenylazoaniline
N,N-Dimethyl-4-aminoazobenzene
Butter Yellow
Solvent Yellow 2
C.I. 11020
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.000.414
EC Number 200-455-7
RTECS number BX7350000
UNII
Properties
C14H15N3
Molar mass 225.30 g·mol−1
Appearance Yellow crystals
Melting point 111–116 °C (232–241 °F; 384–389 K)
decomposes[1]
13.6 mg/l
log P 4.58
Hazards
Main hazards Carcinogen[2]
GHS pictograms [1]
GHS signal word Danger
H301, H351[1]
P281, P301+310[1]
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 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform 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
1
2
0
US health exposure limits (NIOSH):
PEL (Permissible)
 OSHA-regulated carcinogen[2]
REL (Recommended)
 Ca[2]
IDLH (Immediate danger)
 Ca [N.D.][2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Methyl yellow, or C.I. 11020, is a organic compound with the formula C6H5N2C6H4N(CH3)2. It is an azo dye derived from dimethylaniline. It is a yellow solid. According to X-ray crystallography, the C14N3 core of the molecule is planar.[3]

It is used as a dye for plastics may be used as a pH indicator.

Methyl yellow (pH indicator)
below pH 2.9 above pH 4.0
2.9 ⇌ 4.0

In aqueous solution at low pH, methyl yellow appears red. Between pH 2.9 and 4.0, methyl yellow undergoes a transition, to become yellow above pH 4.0.

Safety

It is a possible carcinogen.[2] As "butter yellow", the agent had been used as a food additive before its toxicity was recognized.[4]

See also

Structurally similar compounds:

References

  1. 1 2 3 4 Dimethyl yellow
  2. 1 2 3 4 5 "NIOSH Pocket Guide to Chemical Hazards #0220". National Institute for Occupational Safety and Health (NIOSH).
  3. ↑ A. Whitaker (1992). "Crystal and molecular structure of C.I. Solvent Yellow 2, 1-Phenylazo-4 (N,N-dimethylamine)-phenyl". Journal of Crystallographic and Spectroscopic Research. 22: 151–155. doi:10.1107/S0108270188006791.
  4. ↑ Opie, E. L. (1944). "The Pathogenesis of Tumors of the Liver Produced by Butter Yellow" (pdf). The Journal of Experimental Medicine. 80 (3): 231–246. PMC 2135460 Freely accessible. PMID 19871411. doi:10.1084/jem.80.3.231.
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