Chrysoine resorcinol is a synthetic azo dye which was formerly used as a food additive.[citation needed] In Europe, it was banned as a food additive in 1977.[1] In the US, it was banned in 1988.[2]
Chrysoine resorcinol can be used as a pH indicator with a color change between pH 11 and pH 12.7. In colorimetry, it has an absorption maximum of 387 nm.
| Chrysoine resorcinol (pH indicator) | ||
| below pH 11.0 | above pH 12.7 | |
| 11.0 | ⇌ | 12.7 |
Preparation
Acid orange 6 can be synthesised via the azo coupling of sulfanilic acid and resorcinol,
Notes
- ^ "EUR-Lex - Official Journal of the European Union".
- ^ "Chrysoine Resorcinol Properties, Molecular Formula, Applications - WorldOfChemicals". www.worldofchemicals.com. Retrieved 2022-07-12.
External links