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.

Acid red 88
Kekulé, skeletal formula of acid red 88
Ball-and-stick model of the component ions of acid red 88
IUPAC name
Sodium 4-(2-hydroxy-1-naphthalenylazo)-naphthalenesulfonate
Other names
Fast Red A

2-Naphthol Red
Solid Red A

Toyo roccelline
3D model (JSmol)
ECHA InfoCard 100.015.238 Edit this at Wikidata
EC Number
  • 216-760-3
MeSH Fast+red+S
RTECS number
  • QK2420000
  • 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
  • [Na+].O=S(=O)([O-])c3ccc(N=Nc1c(O)ccc2ccccc12)c4ccccc34
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).
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Preparation and useEdit

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]


  1. ^ Hunger, Klaus; Mischke, Peter; Rieper, Wolfgang; Raue, Roderich; Kunde, Klaus; Engel, Aloys (2005). "Azo Dyes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_245. ISBN 3527306730.
  2. ^ Song, Ya-Li; Li, Ji-Tai; Chen, Hua (2009). "Degradation of C.I. Acid Red 88 aqueous solution by combination of Fenton's reagent and ultrasound irradiation". J. Chem. Technol. Biotechnol. 84 (4): 578–583. doi:10.1002/jctb.2083.
  3. ^ "Acid red 88 | CAS 1658-56-6 | Santa Cruz Biotech". Archived from the original on 2015-07-12. Retrieved 2011-04-24.

External linksEdit