Alizarin (CI 58000) is a chemical compound, a synthetic dye with an anthraquinone unit and is also known as Pigment Red 83.

The dyes that contain anthraquinone (an organic aromatic compound derived from anthracene) have the characteristic of making the colors bright.

Chemical Name

• 1,2-dihydroxyanthracene-9,10-dione

Chemical Industrial Synthesis Process

• Preparation of reagents. The main raw materials include phthalic anhydride, benzene, and concentrated sulfuric acid.
• Synthesis of anthraquinone intermediate. The production of CI 58000 begins with the condensation of phthalic anhydride with benzene in the presence of concentrated sulfuric acid, forming the anthraquinone intermediate.
• Substitution. The anthraquinone is further treated with specific reagents to introduce functional groups that impart the desired color. This may include sulfonation, nitration, or other substitution reactions.
• Oxidation. The functionalized structure undergoes an oxidation reaction to complete the formation of the anthraquinone chromophore, which is responsible for the coloring properties of CI 58000.
• Purification. The crude CI 58000 product is purified using techniques such as crystallization, filtration, and chromatography to remove impurities and achieve a high-purity colorant.
• Stabilization. The purified CI 58000 is stabilized to ensure its stability during transportation and storage, preventing degradation and oxidation.
• Quality control. The CI 58000 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/86 (CI 58000) II/1361 (Pigment Red 83; CI 58000): when used as a substance in hair dye products) a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported:

• 1,2-Dihydroxyanthraquinone

Cosmetica - Funzioni INCI

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

Use in hair colouring products is prohibited.

Molecular Formula     C₁₄H₈O₄

Molecular Weight 

CAS    72-48-0

EC number 200-782-5

UNII 60MEW57T9G

DTXSID5045960

Synonyms: 

Pigment Red 83

CI 58000

Mordant Red 11

Turkey Red