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Congo Red

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Identification
Molecular formula
C32H22N6Na2O6S2
CAS number
573-58-0
IUPAC name
6-amino-3-[[7-[4-[(4-amino-7-sulfo-1-naphthyl)azo]phenyl]azo-8-hydroxy-6-sulfo-2-naphthyl]azo]-4-hydroxy-naphthalene-2-sulfonic acid
State
State

At room temperature, Congo Red is typically found as a crystalline solid in powder form. It is soluble in water, where it exhibits its characteristic red color, and also soluble in ethanol.

Melting point (Celsius)
360.00
Melting point (Kelvin)
633.00
Boiling point (Celsius)
0.00
Boiling point (Kelvin)
0.00
General information
Molecular weight
696.67g/mol
Molar mass
696.6650g/mol
Density
1.4813g/cm3
Appearence

Congo Red appears as a solid powder that ranges in color from red to brown. It is often used as a sodium salt which imparts the vibrant red characteristic. When dissolved in water, it gives a red solution, which can undergo a color change to blue at a low pH.

Comment on solubility

Solubility of 6-amino-3-[[7-[4-[(4-amino-7-sulfo-1-naphthyl)azo]phenyl]azo-8-hydroxy-6-sulfo-2-naphthyl]azo]-4-hydroxy-naphthalene-2-sulfonic acid

The solubility of 6-amino-3-[[7-[4-[(4-amino-7-sulfo-1-naphthyl)azo]phenyl]azo-8-hydroxy-6-sulfo-2-naphthyl]azo]-4-hydroxy-naphthalene-2-sulfonic acid can be characterized by the following points:

  • Water Solubility: This compound is highly soluble in water due to the presence of multiple sulfonic acid groups, which enhance its polar character and affinity for aqueous environments.
  • pH Dependence: The solubility may also be influenced by the pH of the solution. In acidic to neutral pH, the compound generally remains soluble, while in highly alkaline conditions, it may undergo changes that could affect solubility.
  • Temperature Effects: Increased temperature typically improves the solubility of many organic compounds, including this one. However, specific solubility data at varying temperatures would provide more precise insights.
  • Compatibility with Solvents: While it predominantly dissolves in water, the solubility in organic solvents may be limited. It is essential to consider compatibility with various solvent systems for applications.

In conclusion, the solubility characteristics of this complex compound play a crucial role in its applications in dyes and pigments, making it a versatile additive in aqueous formulations.

Interesting facts

Interesting Facts about 6-amino-3-[[7-[4-[(4-amino-7-sulfo-1-naphthyl)azo]phenyl]azo-8-hydroxy-6-sulfo-2-naphthyl]azo]-4-hydroxy-naphthalene-2-sulfonic acid

This compound is a member of the azo dye family, characterized by their vivid colors and high stability, making them popular in various applications. Here are some noteworthy aspects of this specific compound:

  • Complex Structure: The intricate molecular structure of this compound includes multiple naphthalene and azo groups. This complexity contributes to its unique color properties.
  • Applications: Often used in the textile industry, azo dyes are prized for their ability to produce bright and lasting colors on fabrics. Moreover, they may find uses in biological staining processes and as colorants in various materials.
  • Environmental and Health Considerations: While azo dyes are effective, their potential to break down into harmful amines has raised environmental concerns. Researchers are constantly investigating safer alternatives that maintain vibrant colors without adverse effects.
  • Chemical Reactivity: This compound can participate in various chemical reactions, particularly those involving the diazotization process, which is vital for synthesizing a range of azo compounds.
  • Historical Significance: Azo dyes have a rich history dating back to the 19th century, dramatically influencing the development of the dye industry and synthetic colorants.

In summary, the chemical intricacies and diverse applications of this compound make it a fascinating subject of study for chemists and industrial scientists alike. Its vibrant colors not only catch the eye but also open up discussions about sustainability and chemical safety in color production.

Synonyms
6-Amino-3-{[7-({4-[(4-amino-7-sulfonaphthalen-1-yl)diazenyl]phenyl}diazenyl)-8-hydroxy-6-sulfonaphthalen-2-yl]diazenyl}-4-hydroxynaphthalene-2-sulfonic acid
703394-32-5
DTXSID50860030