Methyl yellow

From Wikipedia, the free encyclopedia
  (Redirected from Para-Dimethylaminoazobenzene)
Jump to navigation Jump to search
Methyl yellow
Methyl yellow.svg
Preferred IUPAC name
Other names
Butter Yellow
Solvent Yellow 2
C.I. 11020
3D model (JSmol)
ECHA InfoCard 100.000.414
EC Number 200-455-7
RTECS number BX7350000
Molar mass 225.30 g·mol−1
Appearance Yellow crystals
Melting point 111–116 °C (232–241 °F; 384–389 K)
13.6 mg/l
log P 4.58
Main hazards Carcinogen[2]
GHS pictograms The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)[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
US health exposure limits (NIOSH):
PEL (Permissible)
OSHA-regulated carcinogen[2]
REL (Recommended)
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).
YesY verify (what is YesYNo ?)
Infobox references

Methyl yellow, or C.I. 11020, is an 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.


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[edit]

Structurally similar compounds:


  1. ^ a b c d Dimethyl yellow
  2. ^ a b c d e "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. doi:10.1084/jem.80.3.231. PMC 2135460Freely accessible. PMID 19871411. 

External links[edit]