Chrysoine resorcinol

Chrysoine resorcinol is a synthetic azo dye which was formerly used as a food additive. In Europe, it was banned as a food additive in 1977.[1] In the US, it was banned in 1988.

Chrysoine resorcinol

Names
IUPAC name Sodium 4-[(2,4-dihydroxyphenyl)diazenyl]benzenesulfonate
Other names Sodium p-(2,4-dihydroxyphenylazo)benzenesulfonate; Chrysoine; Resorcinol Yellow; Gold Yellow; Yellow T; Tropaeolin O; Tropaeolin R; C.I. Food Yellow 8; C.I. Acid Orange 6; C.I. 14270
Identifiers
CAS Number	547-57-9 Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	21106427 Y
ECHA InfoCard	100.008.114
EC Number	208-924-8
PubChem CID	6093186
UNII	NF91VMI73L N
CompTox Dashboard (EPA)	DTXSID70873925
InChI InChI=1S/C12H10N2O5S.C6H6O2.Na/c15-9-3-6-11(12(16)7-9)14-13-8-1-4-10(5-2-8)20(17,18)19;7-5-2-1-3-6(8)4-5;/h1-7,15-16H,(H,17,18,19);1-4,7-8H;/q;;+1/p-1/b14-13+;; Y Key: DJYSHZPRWDNEOL-QDBORUFSSA-M Y InChI=1/C12H10N2O5S.Na/c15-9-3-6-11(12(16)7-9)14-13-8-1-4-10(5-2-8)20(17,18)19;/h1-7,15-16H,(H,17,18,19);/q;+1/p-1/b14-13+; Key: COEZWFYORILMOM-WTMITFMSBV InChI=1/C12H10N2O5S.C6H6O2.Na/c15-9-3-6-11(12(16)7-9)14-13-8-1-4-10(5-2-8)20(17,18)19;7-5-2-1-3-6(8)4-5;/h1-7,15-16H,(H,17,18,19);1-4,7-8H;/q;;+1/p-1/b14-13+;; Key: DJYSHZPRWDNEOL-MNMGBGISBV
SMILES [Na+].Oc2cc(O)ccc2/N=N/c1ccc(cc1)S([O-])(=O)=O [Na+].Oc2cc(O)ccc2/N=N/c1ccc(cc1)S([O-])(=O)=O.Oc1cccc(O)c1
Properties
Chemical formula	C12H9N2NaO5S
Molar mass	316.26 g·mol−1
Appearance	Orange-yellow solid
Solubility in water	Partially soluble
Hazards
NFPA 704 (fire diamond)	1 2 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

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.

It can be synthesised via the azo coupling of sulfanilic acid and resorcinol.