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Congo red

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

Solid

At room temperature, congo red is typically in a solid state. It is commonly found as a powder used primarily for its coloring properties.

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
1.0350g/cm3
Appearence

Congo red appears as a red-brown powder or granules. It is a vivid red dye, commonly used for staining in microbiology and an indicator in chemistry due to its color-changing properties depending on pH levels. In acidic solutions, it turns blue, and in alkaline solutions, it remains red.

Comment on solubility

Solubility of 4-amino-3-[4-[4-[(1-amino-4-sulfo-2-naphthyl)azo]-3-chloro-phenyl]-2-chloro-phenyl]azo-naphthalene-1-sulfonic acid

The compound 4-amino-3-[4-[4-[(1-amino-4-sulfo-2-naphthyl)azo]-3-chloro-phenyl]-2-chloro-phenyl]azo-naphthalene-1-sulfonic acid exhibits notable solubility characteristics primarily influenced by its chemical structure. As a sulfonic acid derivative, it is expected to possess significant aqueous solubility due to the presence of strong ionic interactions.

  • Polar Nature: The compound contains multiple polar functional groups, including sulfonic acid (–SO₃H) and amino (–NH₂) groups, which enhance its ability to interact with water molecules.
  • Ionic Interactions: When dissolved, the sulfonic group can ionize, leading to the formation of negative charges that can stabilize the compound in solution.
  • Hydrogen Bonding: The presence of amino groups also allows for hydrogen bonding with water, further promoting solubility.

However, the overall solubility can be influenced by various factors:

  1. pH of the Solution: The solubility may vary with changes in pH, affecting the ionization of the sulfonic and amino groups.
  2. Temperature: As with many compounds, increased temperature generally enhances solubility.
  3. Presence of Other Solutes: The solubility may also be affected in the presence of salts or other solutes, which can lead to precipitation or complexation.

In summary, you can expect 4-amino-3-[4-[4-[(1-amino-4-sulfo-2-naphthyl)azo]-3-chloro-phenyl]-2-chloro-phenyl]azo-naphthalene-1-sulfonic acid to have good solubility in aqueous environments due to its polar and ionic character, making it an interesting compound for various applications.

Interesting facts

Interesting Facts About 4-Amino-3-[4-[4-[(1-amino-4-sulfo-2-naphthyl)azo]-3-chloro-phenyl]-2-chloro-phenyl]azo-naphthalene-1-sulfonic Acid

This complex compound, often referred to as a member of the azo dye family, contains a rich array of functional groups including amines and sulfonic acids. Azo compounds are renowned for their vibrant colors, making them invaluable in various industries, particularly in textiles and printing. Here are some fascinating aspects to consider:

  • Dye Properties: Its azo group (-N=N-) is responsible for the intense coloration, which can vary based on the surrounding chemical environment.
  • Applications: The compound is widely used in textile dyeing, providing deep hues to fabrics. Moreover, its ability to bind to proteins makes it suitable for biological staining techniques.
  • Biological Activity: Some azo dyes have been studied for their potential *antimicrobial* properties, which opens new avenues in medicinal chemistry.
  • Synthetic Pathways: The synthesis of this compound typically involves *diazotization* followed by coupling reactions, showcasing fundamental organic reactions that are crucial for chemistry students to grasp.
  • Environmental Considerations: With increasing awareness of *environmental pollution*, the safety and biodegradability of azo dyes are critical topics in chemistry and sustainability discussions.

The intricate structure of this compound highlights the versatility and complexity of azo dyes, reminding us how chemistry plays a pivotal role in both industry and science. As Greene et al. insightfuly stated, “Chemistry is the bridge between thinking and doing.” This compound exemplifies that bridge, merging theoretical understanding with practical applications.


Synonyms
C.I. Direct Red 61
25188-40-3
SCHEMBL23787654
DTXSID40863858