Sulphanilic Acid
4-Aminobenzenesulfonic Acid, p-Aminobenzenesulfonic Acid.
- CAS
- 121-57-3
- EC
- 204-482-5
- Sectors
- Textiles, Leather & Paper, Pharma & Healthcare
Sulphanilic Acid (CAS 121-57-3) is an aromatic amine sulfonic acid that carries amino and sulfonic acid functional groups, supplied as a greyish-white crystalline solid in Technical Grade and used as an intermediate for azo dyes, optical brighteners and sulfonamide-based pharmaceuticals and as a diagnostic reagent. It is a critical intermediate in the synthesis of Azo Dyes and various sulfonamide-based pharmaceutical products.
The compound is highly valued for its ability to undergo diazotization, a process essential for creating vibrant dyes and pigments used in the textile and food industries. Its high purity (>99%) ensures consistent quality in the production of optical brighteners and food-safe colorants.
In the medical field, it is used as a diagnostic reagent and as a building block for sulfonamides, a class of synthetic antimicrobial agents. Its stable zwitterionic structure provides high thermal stability, making it a reliable precursor for complex industrial organic chemistry.
Sulphanilic Acid reaches textile, leather, paper and pharmaceutical customers through SoleChem in Technical Grade, with stock held for repeat orders. The material ships in 25 kg woven bags with PE liners and in 500 kg fiber drums.
SoleChem supplies these sectors under ISO 9001:2015 certification, with deliveries to more than 40 countries. A certificate of analysis (COA) and safety data sheet (SDS) accompany every delivery. Purchasing teams in textile dyeing, paper brightening and pharmaceutical manufacturing can send their required quantity and packaging preference to request a bulk quote.
Typical Properties
| Molecular formula | C6H7NO3S |
|---|---|
| Molecular weight | 173.19 g/mol |
| Appearance | greyish-white crystals or powder |
| Form | solid |
| Color | White to Off-White |
| Melting point | 288 °C |
| Boiling point | 279 °C |
| Density | 1.485 g/cm³ @ Temp: 25 °C |
| Water solubility | 0.1 g/100 mL (20 °C) |
| pH | 2.5 (10g/l, H2O, 20°C) |
| GHS signal word | Warning · Irritant / harmful |
| HS code | 29214210 |
| Grades available | Technical Grade |
Typical literature values for identification; lot-specific results are stated on the certificate of analysis (COA) and the safety data sheet (SDS) that accompany every delivery.
Applications by Industry
- Textiles, Leather & Paper
Sulphanilic Acid serves textile and paper producers as a primary intermediate for azo dyes such as Acid Orange and Methyl Orange, and in fluorescent whitening agents that raise product brightness.
- Pharma & Healthcare
Sulphanilic Acid acts as a precursor for sulfa drugs and supports medical testing as a reagent for detecting nitrous acid or bilirubin.
Sulphanilic Acid
Applications
- Dye Manufacture: Primary intermediate for the production of Acid Orange, Methyl Orange, and various other azo-based textile and food dyes.
- Optical Brighteners: Used in the synthesis of fluorescent whitening agents for the paper and detergent industries to enhance product brightness.
- Pharmaceuticals: Acts as a precursor for sulfa drugs and as a reagent in medical testing for the detection of nitrous acid or bilirubin.
Safety & Risks
Classified as Skin Sensitizer and Eye Irritant. May cause allergic reactions; wear Nitrile Gloves, Lab Coats, and Eye Protection. Handle in a Dust-Controlled Environment.
Packaging
25 kg Woven Bags with PE liners and 500 kg Fiber Drums.