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)
ChEMBL
ChemSpider
ECHA InfoCard 100.000.414 Edit this at Wikidata
EC Number
  • 200-455-7
RTECS number
  • BX7350000
UNII
  • InChI=1S/C14H15N3/c1-17(2)14-10-8-13(9-11-14)16-15-12-6-4-3-5-7-12/h3-11H,1-2H3/b16-15+ checkY
    Key: JCYPECIVGRXBMO-FOCLMDBBSA-N checkY
  • InChI=1/C14H15N3/c1-17(2)14-10-8-13(9-11-14)16-15-12-6-4-3-5-7-12/h3-11H,1-2H3/b16-15+
    Key: JCYPECIVGRXBMO-FOCLMDBBBF
  • N(=N/c1ccccc1)\c2ccc(N(C)C)cc2
Properties
C14H15N3
Molar mass 225.295 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
Occupational safety and health (OHS/OSH):
Main hazards
 Carcinogen[2]
GHS labelling:
GHS06: ToxicGHS08: Health hazard[1]
Danger
H301, H351[1]
P281, P301+P310[1]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
1
0
NIOSH (US health exposure limits):
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).
checkY verify (what is checkY☒N ?)

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 and 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.

  1. ^ a b c d Dimethyl yellow
  2. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0220". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ Whitaker A (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 (2): 151–155. doi:10.1007/BF01186250. S2CID 93052691.