What does the restriction note for ACID ORANGE 24 mean?

The restriction field for ACID ORANGE 24 reads: II/1232. This is the restriction note from the CosIng inventory. For authoritative conditions and limits, always refer to the linked annex entries.

How do I check if my formula contains ACID ORANGE 24?

Use the INCI Checker to screen a full ingredient list across selected markets, or use the substance market comparison to review this identity across all supported market datasets.

InventoryRef 4171115/10/2010

ACID ORANGE 24

Sodium 4-[[3-[(dimethylphenyl)azo]-2,4-dihydroxyphenyl]azo]benzenesulphonate (CI 20170)

ACID ORANGE 24 is linked to 1 EU annex record on this page. Inventory note: II/1232.

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Regulatory evidence by market

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Market	Evidence status	Records	Source language
European Union	Evidence linked Prohibited entry found Open this evidence	1	English and EU languages
Great Britain	Source mapped Official source mapped; ingredient rule not imported	0	English
Canada	Source mapped Official source mapped; ingredient rule not imported	0	English and French
New Zealand	Source mapped Official source mapped; ingredient rule not imported	0	English
ASEAN	Source mapped Official source mapped; ingredient rule not imported	0	English and national languages
China	Source mapped Official source mapped; ingredient rule not imported	0	Chinese with selected English material
Japan	Source mapped Official source mapped; ingredient rule not imported	0	Japanese; official English translation available
South Korea	Source mapped Official source mapped; ingredient rule not imported	0	Korean with some English names
United States	Source mapped Official source mapped; ingredient rule not imported	0	English
Australia	Source mapped Official source mapped; ingredient rule not imported	0	English
Brazil	Source mapped Official source mapped; ingredient rule not imported	0	Portuguese with INCI crosswalks
India	Source mapped Official source mapped; ingredient rule not imported	0	English and Hindi
Saudi Arabia	Source mapped Official source mapped; ingredient rule not imported	0	Arabic and English

Chemical identity and properties

PubChem 2D chemical structure for CAS 1320-07-6

CAS 1320-07-6PubChem CID 23675104

D&C Brown No. 1

IUPAC name: sodium 4-[(2Z)-2-[(5E)-5-[(2,4-dimethylphenyl)hydrazinylidene]-4,6-dioxocyclohex-2-en-1-ylidene]hydrazinyl]benzenesulfonate

Molecular formula: C20H17N4NaO5S
Molecular weight: 448.4 g/mol
Exact mass: 448.08173511 Da
Topological polar surface area: 149.0 Å²
Hydrogen-bond donors: 2
Hydrogen-bond acceptors: 9
Covalent units: 2
Defined stereocentres: 0

Also known as

Acid orange 24D & C Brown no. 1AO24 dyeEINECS 215-296-9CI 201708796B4I6HEC.I. ACID ORANGE 24, MONOSODIUM SALTBenzenesulfonic acid, 4-((3-((dimethylphenyl)azo)-2,4-dihydroxyphenyl)azo)-, monosodium salt

16 more reported names

BROWN 1Sodium 4-((3-((dimethylphenyl)azo)-2,4-dihydroxyphenyl)azo)benzenesulphonateSodium 4-[[3-[(dimethylphenyl)azo]-2,4-dihydroxyphenyl]azo]benzenesulphonateBenzenesulfonic acid, 4-[[3-[(dimethylphenyl)azo]-2,4-dihydroxyphenyl]azo]-, monosodium saltBenzenesulfonic acid, 4-(2-(3-(2-(dimethylphenyl)diazenyl)-2,4-dihydroxyphenyl)diazenyl)-, sodium salt (1:1)Benzenesulfonic acid, 4-((3-((2,4-dimethylphenyl)azo)-2,4-dihydroxyphenyl)azo)-, monosodium saltBenzenesulfonic acid, 4-[2-[3-[2-(dimethylphenyl)diazenyl]-2,4-dihydroxyphenyl]diazenyl]-, sodium salt (1:1)LEATHER BROWN 2GRefChem:581454C.I. Acid Orange 24FABRACID BROWN S-BMULTICUER BROWN MNOBROWN 1 [INCI]KATSU201KATSU201 [INCI]JAPAN BROWN NO. 201

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEMBL:CHEMBL2105313

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

Inventory details for ACID ORANGE 24

INCI name

ACID ORANGE 24

Description

Sodium 4-[[3-[(dimethylphenyl)azo]-2,4-dihydroxyphenyl]azo]benzenesulphonate (CI 20170)

Record provenance

Inventory reference: 41711
Imported identity: ACID ORANGE 24
Source update: 15/10/2010

European Commission CosIng source notes

Annex records for ACID ORANGE 24

Annex II Restriction reference

Entry 1232

Acid Orange 24 (CI 20170), when used as a substance in hair dye products

CAS: 1320-07-6

EC: 215-296-9

Key data

CAS

1320-07-6 / 6371-84-2

215-296-9

Restriction

II/1232

Function

HAIR DYEING: Imparting color to hair. Hair dyeing preparations may be temporary, semi-permanent, or permanent, depending on the length of time the colorant remains on the hair.

Official EU ingredient-name evidence

The ingredient name exactly matches the official 2025 EU glossary of common ingredient names.

#856 · ACID ORANGE 24

Records sharing a CAS or EC identity

CI 20170

Ingredients with overlapping formulation functions

ACID BLUE 9 ALUMINUM LAKEHAIR DYEING

ACID BLUE 9 AMMONIUM SALTHAIR DYEING

ACID BROWN 13HAIR DYEING

ACID GREEN 1HAIR DYEING

ACID ORANGE 3HAIR DYEING

ACID ORANGE 6HAIR DYEING

ACID ORANGE 7HAIR DYEING

ACID RED 18HAIR DYEING

Additional official and scientific sources

11 external databases to check this identity in

Each link searches that source for this identity. What each source is, and its legal weight

ECHA CHEM / Information on chemicals PubChem PUG REST EU Safety Gate cosmetic product alerts ECHA CHEM US EPA CompTox Cosmetic Ingredient Review safety assessments FDA Global Substance Registration System ILO/WHO International Chemical Safety Cards Japan NITE-CHRIP NIOSH Pocket Guide to Chemical Hazards OECD eChemPortal

How ACID ORANGE 24 appears in the CosIng inventory

The CosIng inventory lists ACID ORANGE 24 as a cosmetic ingredient and this page links it to 1 annex record. The inventory entry captures names and identifiers, while the annex record shows where the substance is prohibited, restricted or positively listed in EU cosmetics law.

ACID ORANGE 24 is also tagged with 1 cosmetic function in the official data. Function labels describe intended use, but they do not replace regulatory review of linked annex records before formulation or labelling work.

Frequently asked questions

ACID ORANGE 24 appears in the EU CosIng inventory and has linked annex records. Check the annex records above for applicable restrictions, concentration limits and conditions of use. Annex II listing means prohibited; Annex III means restricted; Annexes IV, V and VI mean permitted under specified conditions.

The restriction field for ACID ORANGE 24 reads: "II/1232". This is the restriction note recorded in the CosIng inventory for this ingredient. For authoritative conditions and limits, always refer to the linked annex entries above.

According to the EU CosIng inventory, ACID ORANGE 24 carries the following function designation(s):

HAIR DYEING

CAS 1320-07-6 / 6371-84-2 may appear across multiple EU annex records. Viewing the CAS lookup page shows all Annex II–VI entries sharing this identifier, which is useful for identifying cross-annex regulatory status of the same chemical substance.

Use the INCI Checker to screen a full ingredient list across selected markets, or compare this substance across all supported market datasets.

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Source note for ACID ORANGE 24

This page combines the CosIng inventory entry for ACID ORANGE 24 with 1 linked Annex II–VI record from the local dataset built from public European Commission cosmetic ingredient materials.

Use this inventory page to research ACID ORANGE 24 and compare linked records, but verify restrictions and legal status against the current official source text and law before making regulatory decisions.

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Tools & next steps

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