Xylidine Ponceau

Structural formula
General
Surname	Xylidine Ponceau
other names	Disodium 4 - [(2,4-dimethylphenyl) diazenyl] -3-hydroxy-2,7-naphthalene disulfonate ( IUPAC ) CI Acid Red 26 CI Food Red 5 CI 16150 Ponceau 2R Xylidine red
Molecular formula	C 18 H 14 N 2 Na 2 O 7 S 2
Brief description	Dark red to burgundy red powder
External identifiers / databases
CAS number 3761-53-3 EC number 223-178-3 ECHA InfoCard 100,021,072 PubChem 102092631 ChemSpider 21171975 Wikidata Q27105091
properties
Molar mass	480.42 g mol −1
Physical state	firmly
Melting point	> 300 ° C
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 351 P: 281
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Xylidin-Ponceau is a red azo dye from the group of acid dyes that was previously used to dye wool. The dye is used in Masson-Goldner trichrome staining .

The synthesis of xylidine-Ponceau takes place by diazotization of 2,4-xylidine and azo coupling with 3-hydroxynaphthalene-2,7-disulfonic acid (R-acid).

Individual evidence

1. ↑ ^{a b c} Entry on ACID RED 26 at ChemicalBook , accessed November 22, 2019.
2. ↑ ^{a b} Datasheet Ponceau Xylidine, Dye content ≥60% from Sigma-Aldrich , accessed on November 4, 2013 ( PDF ).
3. ^ Rudolf Nietzki: Chemistry of organic dyes . 5th edition. Julius Springer Verlag, Berlin 1906, p. 64 ff . ( limited preview in Google Book search).