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Congo Red

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Identification
Molecular formula
C32H22N6Na2O6S2
CAS number
573-58-0
IUPAC name
3-hydroxy-4-[2-sulfo-5-(4-sulfophenyl)azo-phenyl]azo-naphthalene-2,7-disulfonic acid
State
State

At room temperature, this compound is in a solid state, typically as a fine powder. It is often used as a pH indicator.

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
0.9165g/cm3
Appearence

The compound typically appears as a reddish-brown powder. It is an azo dye, characterized by the presence of azo groups (-N=N-) which often impart vivid colors to compounds. When dissolved, it yields a red solution in basic conditions and blue one in acidic conditions.

Comment on solubility

Solubility of 3-hydroxy-4-[2-sulfo-5-(4-sulfophenyl)azo-phenyl]azo-naphthalene-2,7-disulfonic acid

The compound 3-hydroxy-4-[2-sulfo-5-(4-sulfophenyl)azo-phenyl]azo-naphthalene-2,7-disulfonic acid exhibits unique solubility characteristics primarily due to its highly ionic nature and the presence of multiple sulfonic acid groups. Here are some key points about its solubility:

  • Water Solubility: The presence of multiple sulfonic acid groups enhances the compound's solubility in water, making it highly hydrophilic.
  • pH Dependence: Its solubility may change with the pH of the solution; generally, it is more soluble in acidic or neutral environments.
  • Solvent Suitability: This compound is less likely to dissolve in organic solvents due to its ionic properties, thus favoring polar solvents like water for dissolution.
  • Applications Impact: The solubility plays a crucial role in its applications, particularly in dye chemistry and biological studies where aqueous solutions are often required.

Overall, the solubility profile of this compound underscores the importance of ionic interactions and pH in its behavior in various environments. It serves as a fascinating example of how chemical structure influences solubility.

Interesting facts

Interesting Facts about 3-hydroxy-4-[2-sulfo-5-(4-sulfophenyl)azo-phenyl]azo-naphthalene-2,7-disulfonic acid

This compound is a fascinating member of the azo dye family, known for its vivid colors and wide-ranging applications in various industries. Here are some engaging insights about this particular compound:

  • Azo Dyes Background: Azo compounds are characterized by the presence of one or more azo groups (–N=N–) and are widely used in the textile industry due to their strong coloring properties.
  • Applications: This compound is primarily utilized in textile dyeing and printing, providing bright and durable colors. It's also used in other fields such as paper manufacturing and food industries.
  • Environmental Considerations: The use of azo dyes raises important environmental concerns due to some azo compounds being toxic or carcinogenic. This has led to increased research in finding safer alternatives and improving wastewater treatment processes.
  • Analytical Chemistry: 3-hydroxy-4-[2-sulfo-5-(4-sulfophenyl)azo-phenyl]azo-naphthalene-2,7-disulfonic acid serves as a useful analytical reagent, particularly in spectrophotometry, due to its strong absorbance characteristics at various wavelengths.
  • Color Variations: The specific structure of the compound allows for a range of vibrant hues depending on the pH of the solution, making it a subject of interest in colorimetric studies.

This compound exemplifies the intricate relationship between chemistry and real-world applications, showcasing the blend of scientific principles and artistic expression through color. With ongoing research, the impact and safety of azo dyes continue to evolve, highlighting the importance of balancing industrial utility with environmental health.