Acid red 88

Names
IUPAC name Sodium 4-(2-hydroxy-1-naphthalenylazo)-naphthalenesulfonate
Other names Fast Red A 2-Naphthol Red Roccelline Solid Red A Toyo roccelline
Identifiers
CAS Number	1658-56-6 (E)-diazen Y
3D model (JSmol)	Interactive image
ChemSpider	23621588 N
ECHA InfoCard	100.015.238
EC Number	216-760-3
MeSH	Fast+red+S
PubChem CID	23722700 23669381 (Z)-diazen 23670762 (E)-diazen
RTECS number	QK2420000
UNII	7Z2135Z4K4 (E)-diazen Y
CompTox Dashboard (EPA)	DTXSID1041714
InChI InChI=1S/C20H14N2O4S.Na/c23-18-11-9-13-5-1-2-6-14(13)20(18)22-21-17-10-12-19(27(24,25)26)16-8-4-3-7-15(16)17;/h1-12,20H,(H,24,25,26);/q;+1/p-1 N Key: IVEHGZAIVWEKHA-UHFFFAOYSA-N N
SMILES [Na+].O=S(=O)([O-])c3ccc(N=Nc1c(O)ccc2ccccc12)c4ccccc34
Properties
Chemical formula	C20H13N2NaO4S
Molar mass	400.38 g·mol−1
Appearance	Vivid, dark red, opaque, vitreous solid
Melting point	280 °C (536 °F; 553 K)
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

Acid red 88 is an azo dye. Due to its intense colour, solid samples appear almost black. It is used to dye cotton textiles red.^[1] A closely related acid dye is Acid Red 13.

Preparation and use

It can be obtained by azo coupling of naphthionic acid and 2-naphthol. Instead of crystallising, it vitrifies when cooled or salted out of the solution.

This compound is used in the textile industry as a dye.^[2] It can also be used for research in photocatalysis (as degradation object).^[3]