Substance Information
Substance Information
Data platform availability banner - infocard, search, nanomaterias
REACH Registration data can be found in the new ECHA CHEM database. The old ‘Registered substance factsheets’ will be available on this web site during the transition period but have not been updated since 19 May 2023. More
![](/documents/10162/65869804/echa_chem_logo_300px.png/3ab52b86-2888-247f-9e2b-f08cff02c876?t=1704803484609)
Substance Infocard
IC
4-[(2,4-dihydroxyphenyl)azo]benzenesulphonic acid
EC / List no.: 218-087-0
CAS no.: 2050-34-2
Mol. Formula: C12H10N2O5S
![HELP HELP](https://echa.europa.eu/o/echa-revamp-theme/images/gui/help.png)
Regulatory context
Here you can find all of the regulations and regulatory lists in which this substance appears, according to the data available to ECHA. This substance has been found in the following regulatory activities (directly, or inheriting the regulatory context of a parent substance):
- ECHA Legislations
- Occupational Exposure limits (OELs)
- Emission Limit Values (ELVs)
- Other chemical legislations
REACH - Registration, Evaluation, Authorisation and Restriction of Chemicals Regulation
-
Substances predicted as likely to meet criteria for category 1A or 1B carcinogenicity, mutagenicity, or reproductive toxicity, or with dispersive or diffuse use(s) where predicted likely to meet any classification criterion for health or environmental hazards, or where there is a nanoform soluble in biological and environmental media.
-
Substances indicated, in 2009, as being intended to be registered by at least one company in the EEA.
Previous Legislations
-
Substances listed in the EINECS, ELINCS, or NLP inventories.
Cosmetic Products Regulation
-
Cosmetic Products Regulation, Annex II - Prohibited SubstancesEU. Prohibited Substances: Annex II, Regulation 1223/2009/EC on Cosmetic Products, as amended by Regulation (EU) 2024/996, OJ L of 4 April 2024
![Help Help](https://echa.europa.eu/o/echa-revamp-theme/images/gui/help.png)
Substance names and other identifiers
Regulatory process names
4-((2,4-Dihydroxyphenyl)azo)benzenesulphonic acid
Other
4-(2,4-Dihydroxyphenylazo)benzensulphonic acid
Cosmetic Products Regulation, Annex II - Prohibited Substances
4-[(2,4-dihydroxyphenyl)azo]benzenesulphonic acid
EC Inventory, Other
4-[(2,4-dihydroxyphenyl)azo]benzenesulphonic acid
Pre-Registration process, Other
Acid Orange 6 free acid
Other
Benzenesulfonic acid, 4-((2,4-dihydroxyphenyl)azo)-
Other
IUPAC names
4-[(2Z)-2-(2-hydroxy-4-oxocyclohexa-2,5-dien-1-ylidene)hydrazinyl]benzenesulfonic acid
Other
4-[(E)-2-(2,4-dihydroxyphenyl)diazen-1-yl]benzene-1-sulfonic acid
Other
Other identifiers
2050-34-2
EC Inventory, Pre-Registration process, Cosmetic Products Regulation, Annex II - Prohibited Substances, Other
CAS number