Database/Hair Dyeing/Acid Orange 6
Mostly petroleum · ISO 16128

Is Acid Orange 6 natural?

Mostly not. Synthetic monoazo resorcinol acid dye. Its sulfonate groups (from sulfur trioxide) and sodium counter-ions count as natural origin under the site's counter-ion convention; the coloured carbon skeleton is entirely petrochemical. Same treatment as CI 16185.

INCI nameAcid Orange 6
CAS547-57-9
FormulaC12H9N2NaO5S · 316.27 Da
FunctionHair Dyeing
FeedstockPetrochemical aromatic amines and naphthols coupled into the…

How we scored it

Acid Orange 6 (Tropaeolin O) C12H9N2NaO5S 316.3 Da: 1×SO3 80.1 Da + 1×Na 23.0 Da are mineral-derived (natural) = 103.0 Da; the monoazo resorcinol chromophore 213.2 Da is petrochemical → 103.0/316.3 = 0.33.
What counts. ISO 16128-2 scores the atoms that remain in the final ingredient. Reagents, solvents, catalysts and protecting groups used during manufacture leave no mass behind and are not counted.

Where it comes from

Petrochemical aromatic amines and naphthols coupled into the dye, sulfonated with sulfur trioxide/sulfuric acid and neutralised with sodium hydroxide.

In plain English

A synthetic orange dye used to colour hair, based on a petrochemical azo dye core with a mineral-derived sulfonate group; exact structure uncertain.

CosIng definition: Acid Orange 6 is classed chemically as a monoazo colour. It conforms to the formula:

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 Epicatechin 100% natural origin

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 Lawsonia Inermis Extract 100% natural origin

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 Pyrogallol 100% natural origin

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Structure

2D structure of Acid Orange 6

sodium 4-[(2,4-dihydroxyphenyl)diazenyl]benzenesulfonate

PubChem CID 2728027 ↗

References

  1. 1ISO 16128-1:2016 and ISO 16128-2:2017 — Guidelines on technical definitions and criteria for natural and organic cosmetic ingredients and products. ISO, Geneva.
  2. 2Acid Orange 6. PubChem CID 2728027. National Center for Biotechnology Information. pubchem.ncbi.nlm.nih.gov ↗
  3. 3ACID ORANGE 6. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  4. 4ACID ORANGE 6. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=ACID%20ORANGE%206