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Congo Red

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Identification
Molecular formula
C32H22N6Na2O6S2
CAS number
573-58-0
IUPAC name
disodium;3-[[4-(4-anilino-3-sulfonato-phenyl)azo-1-naphthyl]azo]-4-hydroxy-naphthalene-1-sulfonate
State
State

At room temperature, Congo Red is typically in a solid state, appearing as a fine powder. It is water-soluble and forms colloidal solutions. In aqueous solutions, it can exhibit different colors based on the pH of the solution, which is a characteristic feature exploited in various pH detection applications.

Melting point (Celsius)
360.00
Melting point (Kelvin)
633.15
Boiling point (Celsius)
730.15
Boiling point (Kelvin)
1 003.15
General information
Molecular weight
696.67g/mol
Molar mass
696.6650g/mol
Density
0.9700g/cm3
Appearence

Congo Red is a dark red-brown powder. Its color is due to its structure as an azo dye, which contains two azo groups that provide the intense coloration commonly associated with azo compounds. When dissolved in water or alcohol, it can turn a blue or purple-red color depending on the pH of the solution, making it commonly used as a pH indicator.

Comment on solubility

Solubility of Disodium 3-[[4-(4-anilino-3-sulfonato-phenyl)azo-1-naphthyl]azo]-4-hydroxy-naphthalene-1-sulfonate

This compound, commonly known for its vivid coloring properties, exhibits notable solubility characteristics due to its sulfonate moieties. The presence of these functional groups significantly enhances its ability to dissolve in aqueous solutions. Here are some key points regarding its solubility:

  • Water Solubility: Disodium 3-[[4-(4-anilino-3-sulfonato-phenyl)azo-1-naphthyl]azo]-4-hydroxy-naphthalene-1-sulfonate is highly soluble in water, making it an excellent candidate for applications requiring colorimetric analysis.
  • Temperature Dependency: Its solubility may increase with temperature; therefore, performing solubility experiments at various temperatures can provide better insight into its behavior in different conditions.
  • pH Sensitivity: The solubility of this compound can also vary with pH, as the ionization state of the sulfonate groups plays a critical role in influencing its solubility.

As a general observation, the presence of large organic structures often means that while the compound is water-soluble, it may have limited solubility in nonpolar organic solvents. In summary, the solubility of this compound is enhanced by its ionic nature and functional groups, making it a versatile compound within various chemical applications.

Interesting facts

Interesting Facts about Disodium;3-[[4-(4-anilino-3-sulfonato-phenyl)azo-1-naphthyl]azo]-4-hydroxy-naphthalene-1-sulfonate

Disodium;3-[[4-(4-anilino-3-sulfonato-phenyl)azo-1-naphthyl]azo]-4-hydroxy-naphthalene-1-sulfonate, often referred to by its common name, is a fascinating compound that is primarily used as a dye. Here are some engaging insights about this remarkable chemical:

  • Colorant Properties: This compound exhibits vibrant colors, which makes it highly valuable in the textile industry for dyeing fabrics and paper. The azo group (-N=N-) is pivotal for its vivid hue, contributing to its effectiveness as a colorant.
  • Biological Applications: Due to its sulfonate groups, the compound is water-soluble, enabling its application in biological assays. It can be used as a marker in various lab experiments, enhancing visibility and quantification.
  • Environmental Considerations: The production and use of azo dyes have raised environmental concerns. Understanding the breakdown products of azo compounds is crucial due to their potential toxicity and mutagenicity.
  • Regulatory Status: Given the potential health risks associated with some azo dyes, regulatory bodies have set strict guidelines for their use. It's essential for chemists to stay informed about these regulations to ensure safe handling and application.

As scientists and students, it's imperative to recognize the dual nature of such compounds: they hold great potential for practical applications while also posing challenges that require responsible management. Exploring the intricate chemistry behind compounds like this one can lead to exciting innovations in various fields!