Database/Hair Dyeing/Acid Yellow 1
Mostly petroleum · ISO 16128

Is Acid Yellow 1 natural?

Mostly not. Synthetic dinitro-naphthalenesulfonate dye; the sulfonate/sodium groups are mineral-derived, the nitro-aromatic core is petrochemical.

INCI nameAcid Yellow 1
CAS846-70-8
FormulaC10H4N2Na2O8S · 358.19 Da
FunctionHair Dyeing
FeedstockManufactured by nitration and sulfonation of synthetic naphthol,…

How we scored it

Dinitronaphtholate core C10H4N2O5 (petrochemical aromatic, 232 Da) + sulfonate disodium SO3Na2 (natural Da) → 126/358 = 0.35.
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

Manufactured by nitration and sulfonation of synthetic naphthol, isolated as the disodium salt. No natural-origin route exists for the aromatic core.

In plain English

A synthetic yellow dye used to colour hair. Made from a petrochemical naphthalene core; its sulfonate groups come from a mineral source.

CosIng definition: Acid Yellow 1 is classed chemically as a nitro colour. It conforms to the formula:

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Structure

2D structure of Acid Yellow 1

disodium;5,7-dinitro-8-oxidonaphthalene-2-sulfonate

PubChem CID 2724063 ↗

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 Yellow 1. PubChem CID 2724063. National Center for Biotechnology Information. pubchem.ncbi.nlm.nih.gov ↗
  3. 3ACID YELLOW 1. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  4. 4ACID YELLOW 1. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=ACID%20YELLOW%201