Aurine (dye)

Structural formula
General
Surname	Aurin
other names	CI 43800 4- [bis (4-hydroxyphenyl) methylene] -2,5-cyclohexadienone p -rosolic acid Corallin
Molecular formula	C 19 H 14 O 3
Brief description	red-brown solid
External identifiers / databases
CAS number 603-45-2 EC number 210-041-8 ECHA InfoCard 100.009.129 PubChem 5100 Wikidata Q423995
properties
Molar mass	290.32 g · mol -1
Physical state	firmly
solubility	almost insoluble in water, soluble in acids and alkali solutions
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 315-319-335 P: 261-305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Aurin is a triphenylmethane dye that is used as a pH indicator .

Appearance and properties

Aurine is formed when phenol is heated with oxalic acid in concentrated sulfuric acid , the latter acting as a condensation and oxidizing agent:

The yellow-brown or red substance dissolves in alkalis, fuchsin-red, where it serves as a pH indicator. The sodium salt is used to dye wallpaper and paper. The absorption maximum is at λ = 482 nm.

literature

• Paul Karrer: Textbook of Organic Chemistry , 10th Edition, Georg Thieme Verlag, Stuttgart 1948, p. 643.

Individual evidence

1. ↑ Data Aurin (dye) from Acros, accessed on 23 February 2010 .
2. ↑ Hach-Lange.de: MSDS Rosolic Acid  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (accessed August 11, 2012).  
3. ↑ ^{a b c} Data sheet Aurin (dye) from Sigma-Aldrich , accessed on March 9, 2011 ( PDF ).
4. ↑ S. Hauptmann , J. Graefe, H. Remane : Textbook of Organic Chemistry, VEB Deutscher Verlag für Grundstoffindustrie, Leipzig 1980, p. 694.