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CAS 1 record

CAS 20721-50-0

CAS 20721-50-0 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 20721-50-0
CAS 20721-50-0PubChem CID 88669

Disperse Black 9

Disperse Black 9 is an organic molecular entity. It has a role as a dye. — ChEBI

IUPAC name
2-[4-[(4-aminophenyl)diazenyl]-N-(2-hydroxyethyl)anilino]ethanol
Molecular formula
C16H20N4O2
Molecular weight
300.36 g/mol
Exact mass
300.15862589 Da
XLogP3
1.8
Topological polar surface area
94.4 Ų
Hydrogen-bond donors
3
Hydrogen-bond acceptors
6
Covalent units
1
Defined stereocentres
0

Also known as

2,2'-((p-((p-Aminophenyl)azo)phenyl)imino)diethanol7GKC99M24TCOLOREX DBL9LOWADENE BLACK 9Ethanol, 2,2'-[[4-[(4-aminophenyl)azo]phenyl]imino]bis-EINECS 243-987-52,2'-((4-((4-Aminophenyl)azo)phenyl)imino)bisethanol2,2'-[[4-[(4-aminophenyl)azo]phenyl]imino]bisethanol
16 more reported names
2,2'-((4-((4-Aminophenyl)azo)phenyl)imino)bis(ethanol)Ethanol, 2,2'-((4-((4-aminophenyl)azo)phenyl)imino)bis-Ethanol, 2,2'-((4-(2-(4-aminophenyl)diazenyl)phenyl)imino)bis-2,2'-[4-(4-Aminophenylazo)phenylimino]diethanol4-(4'-ANILINOAZO)-N,N-BIS(2-HYDROXYETHYL)ANILINE4-AMINO-4'-(BIS(.BETA.-HYDROXYETHYL)AMINO)AZOBENZENEEthanol, 2,2'-[[4-[2-(4-aminophenyl)diazenyl]phenyl]imino]bis-2,2'-(4-(4-aminophenylazo)phenylimino)diethanolRefChem:589574DISPERSE BLACK 9 [INCI]4-AMINO-4'-(BIS(BETA-HYDROXYETHYL)AMINO)AZOBENZENE810-919-6C.I. Disperse Black 92,2'-((4-((4-Aminophenyl)diazenyl)phenyl)azanediyl)diethanol2,2'-4-(4-Aminophenyl)azophenyliminobis(ethanol)UNII-7GKC99M24T
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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.

Records for CAS 20721-50-0

1 total
Annex
III
Entry
263

Disperse Black 9

Ethanol, 2,2′-[[4-[(4-aminophenyl) azo]phenyl]imino]bis-

Hair dye substance in non-oxidative hair dye products

EC
243-98-5
Max concentration

How CAS 20721-50-0 is used on this site

CAS 20721-50-0 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 20721-50-0 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

Frequently asked questions

A substance identified by CAS 20721-50-0 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

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