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Sulfanilic acid

CAS Number
121-57-3
EC Number
204-482-5
Chemical Formula
C6H7NO3S
Molecular Weight
173.19 g/mol

Description

Sulfanilic acid (CAS 121-57-3 ), also known as sulphanilic acid, is an aminosulfonic acid used as a key intermediate in the synthesis of azo dyes, optical brighteners, and specialty chemicals. Its bifunctional structure, carrying both amine and sulfonic acid groups, makes it a productive building block for coupling reactions in dye manufacturing and industrial chemical synthesis. In textile dyeing, this compound is diazotized and coupled with naphthol or other aromatic compounds to produce direct and reactive azo dyes used on cotton and wool fibers. The paper and packaging industries rely on it to manufacture fluorescent whitening agents that improve brightness in various coated and uncoated paper grades across the global market. Leather processing operations use derivatives of this acid to achieve consistent, penetrating coloration on finished hides. It also functions as a cross-linking component in polymeric colorants. Furthermore, it is utilized in the production of pigment dispersants for printing inks. The material is supplied as a white to off-white crystalline powder for industrial handling. Technical grade is the standard commercial form, with purity typically specified at 99% minimum for dye intermediate applications. Reagent-grade material is available for laboratory use. Analytical applications often require tighter specifications for consistency. Our product meets rigorous industrial benchmarks to ensure performance in complex chemical synthesis and manufacturing. Contact us for supply of Sulfanilic acid Request Quote

Other Names (Synonyms)

sulphanilic acid | p-aminophenylsulfonic acid | aniline-p-sulphonic acid | aniline-p-sulfonic acid | 4-azanylbenzenesulfonic acid | 4-aminobesylic acid | 4-Aminobenzenesulfonic acid | p-Aminobenzenesulfonic acid

Key Technical Features

  • High Purity Grade standard
  • Consistent Batch Quality
  • Full Regulatory & REACH Support
  • Global Logistics Network enabled

Physical Properties

Melting Point288 °C
Boiling Point279 °C
Density1.485 g/cm³ @ Temp: 25 °C
Appearancegreyish-white crystals or powder
ColorWhite to Off-White
Formsolid
Water Solubility0.1 g/100 mL (20 ºC)
Vapor Pressure0Pa at 25℃
Refractive Index1.5500 (estimate)
pH2.5 (10g/l, H2O, 20℃)
Log P-2.3 at 25℃

Safety & Handling

Warning
GHS07· Irritant

Hazard Statements

H315Causes skin irritation
H317May cause an allergic skin reaction
H319Causes serious eye irritation

Precautionary Statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.
P264Wash … thoroughly after handling.
P272Contaminated work clothing should not be allowed out of the workplace.
P280Wear protective gloves/protective clothing/eye protection/face protection.
P321Specific treatment (see … on this label).
P501Dispose of contents/container in accordance with local regulations.
P265Wash … thoroughly after handling.
P352IF ON SKIN: Wash with plenty of water.
P317Get emergency medical help.
P317Get emergency medical help.
P317If eye irritation persists: Get medical advice/attention. Get emergency medical help.
P364Take off contaminated clothing and wash it before reuse.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code29214210
UN Number2790
ADR Class8
Packing GroupIII
WGK (Germany)1