Methyl yellow

Methyl yellow
IUPAC name p-Dimethylaminoazobenzene
Other names 4-Dimethylaminoazobenzene, N,N-Dimethyl-4-phenylazoaniline, N,N-Dimethyl-4-aminoazobenzene, Butter Yellow, Solvent Yellow 2, C.I. 11020
Identifiers
CAS number	60-11-7 Y
PubChem	6053
ChemSpider	5829 Y
UNII	A49L8E13FD Y
EC number	200-455-7
RTECS number	BX7350000
Jmol-3D images	Image 1
SMILES N(=N/c1ccccc1)\c2ccc(N(C)C)cc2
InChI 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+ Y Key: JCYPECIVGRXBMO-FOCLMDBBSA-N Y 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
Properties
Molecular formula	C14H15N3
Molar mass	225.289 g.mol-1
Appearance	Yellow crystals
Melting point	116 °C (decomp.)
Solubility in water	13.6 mg.l-1
log P	4.58
Hazards
R-phrases	R25, R40
S-phrases	S36/37, S45
Main hazards	Toxic (T)
NFPA 704	1 2 0
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

Methyl yellow, or C.I. 11020, is a chemical compound which 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.

Additional indicators are listed in the article on pH indicators.

As "butter yellow" the agent had been used as a food additive before its toxicity was recognized (Opie EL)

References

• NIOSH Pocket Guide to Chemical Hazards 0220
• Eugene L. Opie. The Pathogenesis of Tumors of the Liver Produced by Butter Yellow. The Journal of Experimental Medicine, Vol 80, 231-246, 1944.

See also

Structurally similar compounds:

• Methyl red
• Oil Yellow DE

External links

• International Chemical Safety Card 1498
• More synonyms
• Mutagenicity testing of some commonly used dyes