Understanding the fundamental properties of a chemical compound is essential for optimizing its use in industrial applications. Congo Red, a well-known synthetic dye and indicator, possesses a unique Congo Red chemical structure that dictates its behavior and effectiveness. This deep dive explores this structure and its associated properties, providing valuable insights for professionals in textile dyeing, paper coloring, and analytical chemistry.

Congo Red, identified by the CAS number 573-58-0, is chemically known as sodium 3,3'-([1,1'-biphenyl]-4,4'-diyl)bis(4-aminonaphthalene-1-sulfonate). Its molecular formula is C32H22N6Na2O6S2. The structure is characterized by a central biphenyl core, with two azo linkages (-N=N-) connecting it to two naphthalene rings. Each naphthalene ring is substituted with an amino group (-NH2) and a sulfonic acid group (-SO3Na). The presence of the two azo groups is what gives Congo Red its deep color and classifies it as an azo dye. The sulfonic acid groups are responsible for its water solubility, a key property that facilitates its use in aqueous applications.

These structural features directly influence Congo Red's performance. As a direct dye, its affinity for cellulosic fibers like cotton and linen is due to hydrogen bonding and van der Waals forces between the dye molecule and the cellulose polymer chains. In paper coloring, this affinity ensures even dye distribution and good color retention. As a pH indicator, the color change is attributed to the protonation and deprotonation of the amino groups and azo linkages, which alters the electronic conjugation system and thus the absorption spectrum of the molecule. Its pH transition range, from blue below 3.0 to red above 5.2, is a direct consequence of these structural changes.

When deciding to buy Congo Red powder, understanding these properties is crucial. The Congo Red solubility in water is generally good, making it easy to prepare working solutions. However, factors like temperature and the presence of salts can affect solubility. When sourcing, partnering with a reliable Congo Red dye supplier ensures you receive a product with consistent properties and purity, which is vital for reproducible results. Evaluating the Congo Red CAS 573-58-0 price should take into account the guaranteed quality and adherence to specifications.

NINGBO INNO PHARMCHEM CO.,LTD. is committed to providing high-quality chemicals with detailed technical information. We understand the importance of the Congo Red chemical structure and its properties for your industrial applications. Our aim is to be your trusted partner, offering consistent quality and reliable supply to support your success.