FAQ

Aniline-2,5-disulfonic acid (CAS No. 98-44-2), also known as 2-amino-1,4-benzenedisulfonic acid, is a versatile compound widely used in the chemical industry, primarily as a dye intermediate.

1. Dye Intermediate

• Manufacturing of Dyes: Serves as a critical intermediate in the synthesis of various dyes, including:
  • Direct Dyes: Such as Direct Fast Blue RGL, which is used for dyeing cotton and other cellulosic fibers.
  • Reactive Dyes: Including Reactive Turquoise Blue KGL, Reactive Light Yellow, and Reactive Orange, which are used for dyeing textiles with high colorfastness.
  • Fluorescent Brighteners: Used to enhance the whiteness and brightness of textiles and paper.

2. Physical and Chemical Properties

• Molecular Formula: C₆H₇NO₆S₂
• Molecular Weight: 253.25 g/mol
• Appearance: Yellow crystalline solid
• Solubility: Highly soluble in water
• Melting Point: >300°C
• Toxicity: Toxic if ingested; causes skin and eye irritation, requiring proper handling and protective measures.

3. Industrial Synthesis

• Production Method: Typically synthesized by sulfonation of m-aminobenzenesulfonic acid using fuming sulfuric acid, followed by dilution, neutralization, decolorization with activated carbon, and salting out with sodium chloride.

4. Applications in Textile and Paper Industries

• Textile Dyeing: Provides vibrant and fast colors for fabrics, ensuring resistance to washing and light exposure.
• Paper Whitening: Enhances the brightness and whiteness of paper products through the use of fluorescent brighteners derived from aniline-2,5-disulfonic acid.

5. Safety and Handling Precautions

• Protective Gear: Operators must wear gloves, goggles, and protective clothing to avoid skin and eye contact.
• Storage: Store in a cool, dry, and well-ventilated area away from heat, flames, and incompatible substances.
• Environmental Considerations: Dispose of waste in accordance with local regulations to prevent environmental contamination.

6. Packaging and Availability

• Packaging Options: Available in various forms, including 5g, 25g, and bulk quantities (e.g., 50 kg drums), to suit different industrial needs.
• Purity: Typically offered in high-purity grades (≥99%) to ensure consistent performance in dye synthesis.