Pigment Violet 36 (CI 73385) it is a chemical compound, a synthetic dye tioindigoide (thioprine is an organosulforate compound and synthetic dye, related to indigo, which is not found in nature but is chemically synthesized. It is prepared by S alkylation of thiosylcylic acid and is composed of beta polymorphs and is also known as Vat violet 2.

Chemical Name

(2E)-5-chloro-2-(5-chloro-7-methyl-3-oxo-1-benzothiophen-2-ylidene)-7-methyl-1-benzothiophen-3-one

5-Chloro-2-(5-chloro-7-methyl-3-oxobenzo[b]thien-2(3H)-ylidene)-7-methylbenzo[b]thiophene-3(2H)-one

Chemical Industrial Synthesis Process

• Preparation of reagents. The main raw materials include thioaniline and concentrated sulfuric acid.
• Synthesis of thioindigoid intermediate. The production of CI 73385 begins with the reaction of thioaniline with concentrated sulfuric acid to form a thioindigoid intermediate.
• Condensation. The thioindigoid intermediate is condensed with additional aromatic derivatives under controlled conditions to form the basic structure of the thioindigoid dye.
• Oxidation. The condensed structure is oxidized using an oxidizing agent, such as hydrogen peroxide, to form the thioindigoid chromophore, which is responsible for the coloring properties of CI 73385.
• Purification. The crude CI 73385 product is purified using techniques such as crystallization, filtration, and chromatography to remove impurities and achieve a high-purity colorant.
• Stabilization. The purified CI 73385 is stabilized to ensure its stability during transportation and storage, preventing degradation and oxidation.
• Quality control. The CI 73385 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 IV101 a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported:

• 5-Chloro-2-(5-chloro-7-methyl-3-oxobenzo[b]thien-2(3H)-ylidene)-7-methylbenzo[b]thiophene-3(2H)-one

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.

Molecular Formula    C₁₈H₁₀Cl₂O₂S₂

Molecular Weight    393.3 g/mol

CAS   5462-29-3

EC number 226-750-0

UNII ZVX9A7UOON

DTXSID8063919

Synonyms: 

Vat violet 2

CI 73385

Vat Violet 6RN

Ciba Red 3B