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Congo Red

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

At room temperature, Congo Red is typically found as a solid in the form of a powder.

Melting point (Celsius)
360.00
Melting point (Kelvin)
633.15
Boiling point (Celsius)
0.00
Boiling point (Kelvin)
0.00
General information
Molecular weight
696.67g/mol
Molar mass
696.6660g/mol
Density
0.9966g/cm3
Appearence

Congo Red appears as a dark purple to red powder or crystalline solid. When dissolved in water, it exhibits a red color at neutral to alkaline pH and changes to blue when acidic. It is commonly used as a pH indicator due to this color-changing property.

Comment on solubility

Solubility of 5-amino-3-[4-[4-[(7-amino-1-hydroxy-3-sulfo-2-naphthyl)azo]phenyl]phenyl]azo-4-hydroxy-naphthalene-2,7-disulfonic acid

This compound possesses a complex structure which significantly influences its solubility characteristics. Generally, the solubility of such aromatic azo compounds can be affected by several factors, including:

  • Functional Groups: The presence of multiple sulfonic acid groups (-SO3H) suggests a high potential for solubility in polar solvents, particularly water.
  • Ionic Nature: The sulfonic acid groups can ionize in aqueous solution, enhancing solubility via electrostatic interactions.
  • Hydrogen Bonding: The -OH groups present can form hydrogen bonds with water molecules, further facilitating solubility.

As a result, this compound is likely to be highly soluble in water, making it suitable for various applications where aqueous solutions are necessary. It’s important to note that:

  1. The pH of the solution can influence solubility due to the ionization of the sulfonic acid groups.
  2. Higher temperatures may also improve solubility, as is commonly observed with many organic compounds.
  3. Polar organic solvents, such as methanol or ethanol, may also dissolve this compound due to similar hydrogen bonding capabilities.

In summary, one can expect that 5-amino-3-[4-[4-[(7-amino-1-hydroxy-3-sulfo-2-naphthyl)azo]phenyl]phenyl]azo-4-hydroxy-naphthalene-2,7-disulfonic acid will exhibit high solubility in polar solvents, mainly due to its ionic and hydrophilic groups. Understanding these solubility traits is crucial for its application in various fields, including dye chemistry and biochemistry.

Interesting facts

Interesting Facts about 5-Amino-3-[4-[4-[(7-amino-1-hydroxy-3-sulfo-2-naphthyl)azo]phenyl]phenyl]azo-4-hydroxy-naphthalene-2,7-disulfonic Acid

This complex compound, often identified as a type of azo dye, is known for its vibrant color and extensive applications in various industries. Here are some captivating aspects of this compound:

  • Azo Dye Family: As a member of the azo dye family, this compound contains the azo group (–N=N–), which is pivotal in conferring distinctive colors. Azo dyes are renowned for their brightness and stability.
  • Applications: This compound finds application in fields such as:
    • Textile Industry: Used for dyeing fabrics due to its vivid shades.
    • Biological Staining: Utilized in laboratory settings for staining cells and tissues.
    • Environmental Science: Assists in tracing pollutants in studies assessing water quality.
  • Structure Insights: The intricate structure showcases:
    • Amino and hydroxyl functional groups that enhance its reactivity.
    • A substantial number of sulfonic acid groups, which contribute to its solubility in water.
    • A naphthalene backbone, which provides stability and contributes to its color properties.
  • Environmental Considerations: Although effective as a dye, some azo dyes are under scrutiny due to potential environmental and health impacts. As a result, there are ongoing studies to ensure safe usage.
  • Historical Context: Azo dyes have a rich history dating back to the mid-19th century, revolutionizing the dyeing industry with their affordability and versatility.

In summary, 5-amino-3-[4-[4-[(7-amino-1-hydroxy-3-sulfo-2-naphthyl)azo]phenyl]phenyl]azo-4-hydroxy-naphthalene-2,7-disulfonic acid is not just a derivative of chemistry but a compound that intertwines science with art through its vibrant applications. As we advance, understanding such compounds will help us innovate while maintaining safety and sustainability.

Synonyms
25180-19-2
Chrome Leather Black CR
NSC75779
SCHEMBL12573539
DTXSID80859730
5-Amino-3-({4'-[(7-amino-1-hydroxy-3-sulfonaphthalen-2-yl)diazenyl][1,1'-biphenyl]-4-yl}diazenyl)-4-hydroxynaphthalene-2,7-disulfonic acid
5-amino-3-[4-[4-[(7-amino-1-hydroxy-3-sulfo-2-naphthyl)azo]phenyl]phenyl]azo-4-hydroxy-naphthalene-2,7-disulfonic acid