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Annex II Entry 1323 21/10/2010

3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products

3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

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Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 1323

Chemical identity and properties

PubChem 2D chemical structure for CAS 16279-54-2
CAS 16279-54-2PubChem CID 3570294

3-Hydroxy-4-((2-hydroxynaphthyl)azo)-7-nitronaphthalene-1-sulphonic acid

IUPAC name
3-hydroxy-4-[(2-hydroxynaphthalen-1-yl)diazenyl]-7-nitronaphthalene-1-sulfonic acid
Molecular formula
C20H13N3O7S
Molecular weight
439.4 g/mol
Exact mass
439.04742094 Da
XLogP3
4.1
Topological polar surface area
174.0 Ų
Hydrogen-bond donors
3
Hydrogen-bond acceptors
9
Covalent units
1
Defined stereocentres
0

Also known as

1-Naphthalenesulfonic acid, 3-hydroxy-4-(2-(2-hydroxy-1-naphthalenyl)diazenyl)-7-nitro-1-(2-Hydroxy-4-sulfo-6-nitro-1-naphthylazo)-2-naphthol3-hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid1-Naphthalenesulfonic acid, 3-hydroxy-4-[2-(2-hydroxy-1-naphthalenyl)diazenyl]-7-nitro-RefChem:502386240-379-1Solochrome Black AS, (free acid)C.I. Mordant Black 1, free acid
13 more reported names
C.I. Mordant Black 11-Naphthalenesulfonic acid, 3-hydroxy-4-[(2-hydroxy-1-naphthalenyl)azo]-7-nitro-1-Naphthalenesulfonic acid, 3-hydroxy-4-((2-hydroxy-1-naphthalenyl)azo)-7-nitro-EINECS 240-379-1NCIMech_00030092V9SVJ8HAEriochrome Black A, Free Acid1-(2-Hydroxy-4-sulfo-6-nitro-1-naphthylazo-2-naphtholSXYCCJAPZKHOLS-UHFFFAOYSA-NCCG-35374NCI60_0416073-hydroxy-4-(1-hydroxy-2-napthylazo)-7-nitro-1-naphthalene sulfonic acid3-Hydroxy-4-[2-(2-hydroxy-1-naphthalenyl)diazenyl]-7-nitro-1-naphthalenesulfonic acid
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

PubChem 2D chemical structure for CAS 5610-64-0
CAS 5610-64-0PubChem CID 76960928

Acid Black 52

IUPAC name
trisodium;bis(chromium(3+));tris(7-nitro-3-oxido-4-[(2-oxidonaphthalen-1-yl)diazenyl]naphthalene-1-sulfonate)
Molecular formula
C60H30Cr2N9Na3O21S3
Molecular weight
1482.1 g/mol
Exact mass
1480.922155 Da
Topological polar surface area
547.0 Ų
Hydrogen-bond donors
0
Hydrogen-bond acceptors
27
Covalent units
8
Defined stereocentres
0

Also known as

C.I. Acid Black 52UNII-C2VLY70GFUC2VLY70GFUHSDB 4205EINECS 227-029-3CHROMOLAN BLACK NWAACID BLACK 52 [HSDB]EC 227-029-3
11 more reported names
CI 15711CI-15711C.I. 15711Chromate(3-), bis(3-hydroxy-4-((2-hydroxy-1-naphthalenyl)azo)-7-nitro-1-naphthalenesulfonato(3-))-, disodium hydrogenRefChem:552547ACID BLACK 52 [INCI]227-029-33-Hydroxy-4-((2-hydroxy-1-napthalenyl)azo)-7-nitro-1-naphthalenesulfonic acid, monosodium salt, chromium complex3Hydroxy4((2hydroxy1naphthalenyl)azo)7nitro1naphthalenesulfonic acid, monosodium salt, chromium complexChromate(3), bis(3hydroxy4((2hydroxy1naphthalenyl)azo)7nitro1naphthalenesulfonato(3)), disodium hydrogenPalatine Fast Black WAN
Open full PubChem recordPubChem annotations3D structure image

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Chemical name

3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products

Regulatory information

Regulation

(EC) 2009/1223

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SCCS opinions

Identified ingredients

Key data

CAS
16279-54-2 / 5610-64-0
EC
240-379-1 / 227-029-3
Annex
II
Entry number
1323

Inventory links for 3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products

Inventory Restriction reference
Ref 31608

ACID BLACK 52

CAS: 5610-64-0
EC: 227-029-3

Direct matches are limited for this record, so nearby entries from Annex II are shown as well.

What Annex II means for 3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products

3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009 and must not be intentionally added. Article 17 separately addresses unintended small quantities that are technically unavoidable under good manufacturing practice and compatible with the Article 3 safety requirement.

Formulators must screen their ingredients and raw materials to ensure none contain this substance. Suppliers should provide documentation confirming absence when requested.

This record is linked to 1 CosIng inventory ingredient for name and identifier cross-reference. The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.

Compliance checklist

  • Verify this substance is absent from all raw materials and finished formulations.
  • Request absence confirmation or CoA from raw material suppliers.
  • Document the screening result in the Product Information File (PIF).

Frequently asked questions

Yes. 3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products is listed in Annex II of EU Cosmetics Regulation 1223/2009 and is prohibited as an intentionally added cosmetic ingredient. Article 17 provides a narrow exception for unintended small quantities that are technically unavoidable under good manufacturing practice, provided the product remains safe under Article 3.

CAS 16279-54-2 / 5610-64-0 is the unique numerical identifier assigned to 3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex II record 3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products

This page summarizes one Annex II record for 3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.

Use this record page to review Annex II conditions for 3-Hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid and its salts, when used as a substance in hair dye products, but confirm any final regulatory decision against the current official annex wording and source files.

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