Methyl yellow

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Methyl yellow
Names
IUPAC name
N,N-Dimethyl-4-(phenyldiazenyl)aniline
Other names
4-Dimethylaminoazobenzene
Butter Yellow
C.I. 11020
DAB
N,N-Dimethyl-4-aminoazobenzene
N,N-Dimethyl-4-phenylazoaniline
p-Dimethylaminoazobenzene
Solvent Yellow 2
Properties
C14H15N3
C6H5N2C6H4N(CH3)2
Molar mass 225.295 g/mol
Appearance Yellow solid
Odor Odorless
Density 1.2233 g/cm3[1]
Melting point 110–112 °C (230–234 °F; 383–385 K) [3]
Boiling point Decomposes
0.00136 g/100 ml
Solubility Soluble in ethanol, pyridine
Solubility in pyridine 28 g/100 g (22.5 °C)[2]
Vapor pressure ~0 mmHg
Thermochemistry
Hazards
Safety data sheet Fisher Scientific
Lethal dose or concentration (LD, LC):
200 mg/kg (rat, oral)
Related compounds
Related compounds
Methyl orange
Methyl red
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Methyl yellow, or C.I. 11020, is an organic chemical compound, an azo dye, sometimes used as pH indicator.

Properties

Chemical

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.

Physical

Methyl yellow is a yellowish solid, almost insoluble in water, but more soluble in alcohols.

Availability

Methyl yellow is sold by chemical suppliers.

Preparation

Methyl yellow can be synthesized from the diazotization reaction of aniline with N,N-dimethylaniline, using sodium nitrite with hydrochloric acid, at low temperatures.[6][7][8] Yield of this process varies between 84 to 97%, depending on the method.

Projects

  • pH indicator

Handling

Safety

Methyl yellow displays moderate toxicity. It is classified as a possible carcinogen.

Storage

In closed bottles.

Disposal

Can be destroyed using strong oxidizing solutions suited for neutralizing aromatics, like Fenton's reagent or piranha solution, or using a strong oxidizing solution and strong UV light, from a UV lamp.

References

  1. Whitaker, A.; Journal of Crystallographic and Spectroscopic Research; vol. 22; nb. 2; (1992); p. 151 - 155
  2. Dehn; Journal of the American Chemical Society; vol. 39; (1917); p. 1400
  3. Valizadeh, Hassan; Shomali, Ashkan; Nourshargh, Saideh; Mohammad-Rezaei, Rahim; Dyes and Pigments; vol. 113; (2015); p. 522 - 528
  4. Lemoult; Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences; vol. 143; (1906); p. 604
  5. Annales de Chimie (Cachan, France); vol. <8>14; (1908); p. 300
  6. Valizadeh, Hassan; Shomali, Ashkan; Dyes and Pigments; vol. 92; nb. 3; (2012); p. 1138 - 1143
  7. Bahulayan, Damodaran; John, Litka; Lalithambika, Malathy; Synthetic Communications; vol. 33; nb. 6; (2003); p. 863 - 869
  8. Gomez-Vallejo, Vanessa; Borrell, Jose I.; Llop, Jordi; European Journal of Medicinal Chemistry; vol. 45; nb. 11; (2010); p. 5318 - 5323

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