Tropeolins are chemicals belonging to the class of monoazo dyes .
Content
Nomenclature
There are several substances related to tropeolins:
- Tropeolin 0 (sodium salt of 4- (2,4-dihydroxyphenylazo) benzenesulfonic acid, resorcinol yellow, chrysoin)
- Tropeolin 00 (sodium salt of 4- (4-anilinophenylazo) benzenesulfonic acid, diphenylamine orange, orange IV, solid yellow, aniline yellow, acid orange 5)
- Tropeolin 000 (4- (4-hydroxy-1-naphthylazo) sodium benzenesulfonic acid, orange I, Ξ±-naphthol orange)
- Tropeolin Zh (sodium salt of 3- (4-anilinophenylazo) benzenesulfonic acid, methanyl yellow, Victoria yellow)
Properties
Tropeolins are crystalline substances, highly soluble in water and poorly soluble in ethanol (except for tropeolin 0, highly soluble in ethanol):
| Substance | Molar mass | Appearance | Coloring transition | pH transition |
|---|---|---|---|---|
| Tropeolin 0 | 316.27 | Red crystals | Yellow - Orange Brown | 11.1 - 12.7 |
| Tropeolin 00 | 375.38 | Orange brown crystals | Red - yellow | 1.3 - 3.2 |
| Tropeolin 000 | 350.33 | Reddish Brown Crystals | Yellow green pink | 7.4 - 8.9 |
| Tropeolin F | 375.38 | Yellow crystals | Red - yellow | 1,2 - 2,3 |
The chemical properties of tropeolins are the same as those of other azo dyes .
Receiving and applying
Tropeolins are synthesized by diazotization of sulfanilic acid and a further azo coupling reaction of the obtained product with resorcinol (tropeolin 0), diphenylamine (tropeolin 00) or Ξ±-naphthol (tropeolin 000). Tropeolins are used as acid-base indicators and for the photometric determination of certain metals.
Literature
- Chemical Encyclopedia / Editorial: Zefirov N.S. et al. - M .: Big Russian Encyclopedia, 1998. - T. 5 (Three-Yatr). - 783 s. - ISBN 5-85270-310-9 .
- Lurie Yu. Yu. Handbook of analytical chemistry. - M .: Chemistry, 1989 .-- 448 p. - ISBN 5-7245-0000-0 .