Pyranine (CI 59040) is a chemical compound, a synthetic green dye with a unit of pyrene and is also known as Solvent Green 7.

Chemical Name:

•  trisodium;8-hydroxypyrene-1,3,6-trisulfonate

Dyes that contain pyrene (a hydrophobic polycyclic aromatic hydrocarbon with interesting photophysical properties that give it high and long fluorescence yields) are characterised by brightness of colour.

Chemical Industrial Synthesis Process

• Preparation of reagents. The main raw materials include pyrene, anhydrous aluminum chloride, and phthalic anhydride.
• Synthesis of pyrene intermediate. The production of CI 59040 begins with the reaction of pyrene with phthalic anhydride in the presence of anhydrous aluminum chloride as a catalyst, forming a pyrene-phthalic intermediate.
• Condensation. The pyrene-phthalic intermediate undergoes a condensation reaction with additional aromatic derivatives in the presence of specific catalysts, forming the basic structure of the dye.
• Acylation and substitution. The basic structure is further functionalized through acylation and substitution reactions to introduce functional groups that impart the desired green color.
• Oxidation. The functionalized structure undergoes an oxidation reaction to complete the formation of the chromophore structure of the dye, which is responsible for the coloring properties of CI 59040.
• Purification. The crude CI 59040 product is purified using techniques such as crystallization, filtration, and chromatography to remove impurities and achieve a high-purity colorant.
• Stabilization. The purified CI 59040 is stabilized to ensure its stability during transportation and storage, preventing degradation and oxidation.
• Quality control. The CI 59040 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/87 (CI 59040) II/1362 (Solvent Green 7; CI 59040): 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:

• Trisodium 8-hydroxypyrene-1,3,6-trisulphonate

Safety

It is an ingredient that has some important health-related contraindications: it should not come into contact with mucous membranes.

Use in hair colouring products is prohibited.

Ingredient that makes the final product more attractive from an aesthetic point of view, but can pose a potential health risk with undesirable side effects especially when used continuously as it can be absorbed through the skin or mucous membranes.

Molecular Formula    C₁₆H₇Na₃O₁₀S₃

Molecular Weight  524.4 g/mol

CAS   6358-69-6

EC number 228-783-6

UNII I2W85YOX9L

DTXSID4041739

DTXSID00275670

Synonyms: 

Solvent Green 7

CI 59040

D&C Green No. 8