Sulfanilic acid
CAS 121-57-3
EC 204-482-5
Formula C6H7NO3S
MW 173.19 g/mol
Pigments & Colorants Textile, Leather & PaperPrinting & Packaging Cross-linking & Curing
Description
Sulfanilic acid (CAS 121-57-3, EC 204-482-5), also known as p-sulfoaniline, 4-sulfoaniline, and sulphanilic acid, is an aromatic aminosulfonic acid produced by the sulfonation of aniline. It carries no assigned E-code and is classified under HS code 29214210.
In textile dyeing, sulfanilic acid acts as a diazonium coupling component, reacting with naphthol derivatives to form stable azo colorants directly on fibre. In paper and leather processing, its bifunctional amine and sulfonate groups enable cross-linking reactions that improve wet strength and surface durability.
Sulfanilic acid is supplied as a technical-grade greyish-white crystalline powder, with purity specifications typically ranging from 98% to 99.5%. The substance is registered under REACH and must be handled in accordance with applicable EU chemical regulations. Standard packaging includes 25 kg bags or fibre drums.
In textile dyeing, sulfanilic acid acts as a diazonium coupling component, reacting with naphthol derivatives to form stable azo colorants directly on fibre. In paper and leather processing, its bifunctional amine and sulfonate groups enable cross-linking reactions that improve wet strength and surface durability.
Sulfanilic acid is supplied as a technical-grade greyish-white crystalline powder, with purity specifications typically ranging from 98% to 99.5%. The substance is registered under REACH and must be handled in accordance with applicable EU chemical regulations. Standard packaging includes 25 kg bags or fibre drums.
Physical Properties
| Melting Point | 288 °C |
| Boiling Point | 279 °C |
| Density | 1.485 g/cm³ @ Temp: 25 °C |
| Appearance | greyish-white crystals or powder |
| Color | White to Off-White |
| Form | solid |
| Water Solubility | 0.1 g/100 mL (20 ºC) |
| Vapor Pressure | 0Pa at 25℃ |
| Refractive Index | 1.5500 (estimate) |
| pH | 2.5 (10g/l, H2O, 20℃) |
| Log P | -2.3 at 25℃ |
Safety & Handling (Learn More)
Warning GHS07
H
H315H317H319
P
P261P264P272P280P321P501P264+P265P302+P352P332+P317P333+P317P337+P317P362+P364P305+P351+P338
Trade & Regulatory
| HS Code | 29214210 |
| UN Number | 2790 |
| ADR Class | 8 |
| Packing Group | III |
| WGK (Germany) | 1 |
Other Names
4-aminobenzenesulfonic acidsulphanilic acid4-aminobesylic acidaniline-p-sulfonic acidp-Sulfoaniline4-SULFOANILINE
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