Acid Green 9  (CI 42100) is a synthetic triphenylmethane blue dye. Triphenylmethane is a hydrocarbon.

Chemical Name: 

sodium;3-[[4-[(2-chlorophenyl)-[4-[ethyl-[(3-sulfonatophenyl)methyl]azaniumylidene]cyclohexa-2,5-dien-1-ylidene]methyl]-N-ethylanilino]methyl]benzenesulfonate

What it is used for and where

Cosmetics

Restricted cosmetic ingredient as IV/64 a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported: Hydrogen [4-[(2-chlorophenyl)[4-[ethyl(3-sulphonatobenzyl)amino]phenyl]methylene]cyclohexa-2,5-dien-1-ylidene](ethyl)(3-sulphonatobenzyl)ammonium, sodium salt

Safety

 It is an ingredient that has some important health-related contraindications: it should only be used in cosmetic products that have contact with the skin for a short time.

Molecular Formula     C₃₇H₃₄ClN₂NaO₆S₂

Molecular Weight    725.2 g/mol

CAS   4857-81-2

EC number 225-458-0

UNII 350YUK2Q7J

DTXSID50881402

Synonyms: 

CI 42100

Acid Brilliant Green 6B

Night Green A

Eriogreen

Folan Green B

Brilliant Acid Green

Acid Leather Green KGB

Milling Green