Database/Hair Dyeing/Pigment Red 4
100% petroleum · ISO 16128

Is Pigment Red 4 natural?

No. The diazo component (chloronitroaniline) and the coupling component (2-naphthol) both come from petrochemical benzene and naphthalene, leaving no natural-origin atoms.

INCI namePigment Red 4
CAS2814-77-9
FormulaC16H10ClN3O3 · 327.72 Da
FunctionHair Dyeing
FeedstockDiazotised 2-chloro-4-nitroaniline is coupled with 2-naphthol, and the…

How we scored it

C16H10ClN3O3 327.7 Da: chloronitrophenyl azo naphthol, entirely benzene and naphthalene chemistry with no natural fragment: 0/327.7 = 0.00.
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

Diazotised 2-chloro-4-nitroaniline is coupled with 2-naphthol, and the pigment is filtered and dried. No natural route exists.

In plain English

A red synthetic azo pigment made from petroleum-derived 2-chloro-4-nitroaniline and 2-naphthol. It is listed in cosmetics as a hair dye or colorant, where the insoluble particles give colour.

CosIng definition: Pigment Red 4 is classed chemically as a monoazo colour. It conforms to the formula:

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Structure

2D structure of Pigment Red 4

1-[(2-chloro-4-nitrophenyl)diazenyl]naphthalen-2-ol

PubChem CID 17778 ↗

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. 2Pigment Red 4. PubChem CID 17778. National Center for Biotechnology Information. pubchem.ncbi.nlm.nih.gov ↗
  3. 3PIGMENT RED 4. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  4. 4PIGMENT RED 4. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=PIGMENT%20RED%204