Pigment Red 122 (CI 73915) is a chemical compound, a synthetic indigoid dye (a special kind of blue dye that can be extracted naturally from plants or obtained synthetically, by chemical reaction as in this case, and which is the oldest form of colouring).

Chemical Name

5,12-Dihydro-2,9-dimethylquino[2,3-b]acridine-7,14-dione

2,9-dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione

Chemical Industrial Synthesis Process

• Preparation of reagents. The main raw materials include indole and concentrated sulfuric acid.
• Synthesis of intermediate. The production of CI 73915 begins with the sulfonation of indole by reacting it with concentrated sulfuric acid, forming a sulfonated intermediate.
• Condensation. The sulfonated intermediate is reacted with additional aromatic derivatives under controlled conditions to form the basic structure of the indigoid dye.
• Oxidation. The basic structure is oxidized using an oxidizing agent such as hydrogen peroxide to form the indigoid chromophore, which is responsible for the coloring properties of CI 73915.
• Neutralization. The oxidized product is neutralized with a base, such as sodium hydroxide, to obtain the sulfonated indigo salt.
• Purification. The crude CI 73915 product is purified using techniques such as crystallization, filtration, and chromatography to remove impurities and achieve a high-purity colorant.
• Stabilization. The purified CI 73915 is stabilized to ensure its stability during transportation and storage, preventing degradation and oxidation.
• Quality control. The CI 73915 undergoes rigorous quality testing to ensure it meets standards for purity, color intensity, and safety. These tests include chemical analysis, spectroscopy, and microbiological testing.

What it is used for and where

Cosmetics 

Restricted cosmetic ingredient as IV/103 a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported:

• 5,12-Dihydro-2,9-dimethylquino[2,3-b]acridine-7,14-dione

Cosmetics - INCI Functions

Colorant. This ingredient has the function of colouring the solution in which it is inserted in a temporary, semi-permanent or permanent manner, either alone or in the presence of the complementary components added for colouring.

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   C₂₂H₁₆N₂O₂

Molecular Weight    340.4 g/mol

CAS   980-26-7

EC number 213-561-3

UNII 28UCS3P84C

DTXSID2052655

MFCD00071968

Synonyms: 

CI 73915

Hostaperm Pink E

2,9-Dimethyl quinacridone