D&C Red No. 36 is a chemical compound, a synthetic dye known as DC Red No. 36 o Pigment Red 4, CI 12085.

Chemical name: 1-[(2-Chloro-4-nitrophenyl)azo]-2-naphthol and its insoluble barium, strontium and zirconium lakes, salts and pigments

What it is used for and where

Cosmetics 

Restricted cosmetic ingredient IV/9 (CI 12085) II/1345 (Pigment Red 4)  as the relevant item in the Annexes to the European Cosmetics Regulation No. 1223/2009. Reported substance or ingredient: 1-[(2-Chloro-4-nitrophenyl)azo]-2-naphthol and its insoluble barium, strontium and zirconium lakes, salts and pigments. Maximum concentration in ready for use preparation 3%.

It’s an ingredient that makes the final product more aesthetically appealing, but can pose a potential risk to human health with unwanted side effects especially when used continuously as it can be absorbed by the skin or mucous membranes.

Safety

The problem related to azo dyes (monoazo or diazo) is photocatalytic degradation that leads to possible oxidation and subsequent formation of impurities such as aromatic amines some of which have carcinogenic activity.. (Konstantinou, I. K., & Albanis, T. A. (2004). TiO2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations: a review. Applied Catalysis B: Environmental, 49(1), 1-14.)

On this dye have been concentrated some studies that have found the dangerousness. (Kupradinun, P., Rienkijakaru, M., Tanyakaset, M., Tepsuwan, A., & Kusamran, W. R. (2002). Carcinogenicity Testing of the Cosmetic Dye: D and C Red No. 36. Asi. Pac. J. of Canc. Pre, 3, 55-60.)

Molecular Formula    C₁₆H₁₀ClN₃O₃

Molecular Weight  

CAS  2814-77-9

UNII    OE8ZA0KN9Z

EC Number  220-562-2

DTXSID7044637

Synonyms:

CI 12085 

Pigment Red 4

Red 36