CI 16185 is a chemical compound, an azo synthetic red dye also known by the name Food Red 9 o Acid Red 27

Chemical name:

 trisodium;3-hydroxy-4-[(4-sulfonatonaphthalen-1-yl)diazenyl]naphthalene-2,7-disulfonate

Chemical Industrial Synthesis Process

• Synthesis of Precursors. Production begins with the synthesis of chemical precursors, typically including aromatic compounds that will be used to form the azo group. These compounds can be derived from anilines or other aromatic amine compounds.
• Formation of the Azo Group. The key reaction in the production of CI 16185 is diazotization, where an aromatic amine compound is treated with nitrous acid (HNO2) to form a diazonium salt. This diazonium salt is then coupled with a phenolic or aromatic amine compound to form the azo group.
• Coupling. The coupling reaction occurs in an alkaline environment and requires controlled conditions of temperature and pH to ensure effective formation of the azo bond and the correct color hue.
• Purification. After the coupling reaction, the dye may contain impurities or by-products that need to be removed. Purification is carried out using techniques such as crystallization, filtration, and washing to obtain a pure final product.
• Drying and Milling. The purified dye is dried and then ground into a fine powder to facilitate its use in product formulations.
• Quality Control. CI 16185 undergoes rigorous quality control checks to verify its purity, color hue, and absence of contaminants. These tests can include spectroscopic analyses, chromatographic analyses, and solubility tests.

Safety

The problem associated with azo dyes (monoazo or diazo) is photocatalytic degradation leading to eventual oxidation and subsequent formation of impurities such as aromatic amines some of which have carcinogenic activity (1).

Use in hair colouring products is prohibited.

What it is used for and where

CI 16185 is a synthetic dye commonly used in a variety of cosmetic and food products. Also known as Acid Red 27 or Erythrosine B, this substance is valued for its intense red hue and is employed to impart color to products such as beverages, sweets, cosmetics, and personal care products.

Cosmetics

It is a restricted ingredient as IV/33 (CI 16185) II/1350 (Acid Red 27; CI 16185: 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 3-hydroxy-4-(4'-sulphonatonaphthylazo)naphthalene-2,7-disulphonate.

Purity criteria as set out in Commission Directive 95/45/EC (E 123)

Colorant. It is an 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   C₂₀H₁₁N₂Na₃O₁₀S₃     C₂₀H₁₁N₂O₁₀S₃.3Na

CAS  915-67-3

Molecular Weight    604.5 g/mol

 EC number    213-022-2

UNII 37RBV3X49K

DTXSID2021232

Synonyms:

• Food Red 9 
• Acid Red 27
• Amaranth Dye
• AR27 Compound
• FD and C Red No. 2
• Azorubin S
• Red Dye No. 2

References________________________________________________________________________

(1) Chung KT, Stevens SE Jr, Cerniglia CE. The reduction of azo dyes by the intestinal microflora. Crit Rev Microbiol. 1992;18(3):175-90. doi: 10.3109/10408419209114557.

Abstract. Azo dyes are widely used in the textile, printing, paper manufacturing, pharmaceutical, and food industries and also in research laboratories. When these compounds either inadvertently or by design enter the body through ingestion, they are metabolized to aromatic amines by intestinal microorganisms. Reductive enzymes in the liver can also catalyze the reductive cleavage of the azo linkage to produce aromatic amines. However, evidence indicates that the intestinal microbial azoreductase may be more important than the liver enzymes in azo reduction. In this article, we examine the significance of the capacity of intestinal bacteria to reduce azo dyes and the conditions of azo reduction. Many azo dyes, such as Acid Yellow, Amaranth, Azodisalicylate, Chicago Sky Blue, Congo Red, Direct Black 38, Direct Blue 6, Direct Blue 15, Direct Brown 95, Fast Yellow, Lithol Red, Methyl Orange, Methyl Red, Methyl Yellow, Naphthalene Fast Orange 2G, Neoprontosil, New Coccine, Orange II, Phenylazo-2-naphthol, Ponceau 3R, Ponceau SX, Red 2G, Red 10B, Salicylazosulphapyridine, Sunset Yellow, Tartrazine, and Trypan Blue, are included in this article. A wide variety of anaerobic bacteria isolated from caecal or fecal contents from experimental animals and humans have the ability to cleave the azo linkage(s) to produce aromatic amines. Azoreductase(s) catalyze these reactions and have been found to be oxygen sensitive and to require flavins for optimal activity. The azoreductase activity in a variety of intestinal preparations was affected by various dietary factors such as cellulose, proteins, fibers, antibiotics, or supplementation with live cultures of lactobacilli.