Products Description
4,4'-Diamino-2,2'-stilbenedisulfonic acid (CAS No. 81-11-8), commonly referred to as amsonic acid, is a pale yellow crystalline powder. It mainly functions as a vital intermediate for synthesizing fluorescent whitening agents and optical brighteners widely applied in the textile and paper industries. This water-soluble compound has amino and sulfonic acid groups attached to a stilbene skeleton, serving as an essential chemical raw material for manufacturing dyes and brightening additives.
Chemical Properties
| Melting point | 300 °C |
| Density | 1.4732 (rough estimate) |
| Vapor pressure | 1.3hPa at 25℃ |
| Refractive index | 1.6510 (estimate) |
| Storage temp | Keep in dark place,Inert atmosphere,Room temperature |
| Solubility | Aqueous Base (Slightly) |
| Pka | -1.58±0.50(Predicted) |
| Form | Crystalline Powder |
| Color | Cream to yellow-brown |
| Water Solubility | <0.1 g/100 mL at 23 ºC |
| Merck | 14595 |
| BRN | 629516 |
| Stability | Stable. Combustible. Incompatible with iron, strong oxidizing agents. |
| LogP | -1.7--1.42 at 25℃ |
| CAS DataBase Reference | 81-11-8(CAS DataBase Reference) |
| EPA Substance Registry System | Amsonic acid (81-11-8) |
Safety Information
| Hazard Codes | C,Xn |
| Risk Statements | 34-22-36/37/38-20/21/22 |
| Safety Statements | 24/25-45-36/37/39-26-22 |
| RIDADR | UN 2583 |
| RTECS | WJ6603000 |
| TSCA | Yes |
| HS Code | 29215900 |
| Hazardous Substances Data | 81-11-8(Hazardous Substances Data) |
Product Applications
It is mainly used for the production of optical brighteners, as well as Direct Yellow G and Direct Yellow R dyes, and can also be incorporated into pesticide formulations.
Moreover, it acts as a key intermediate for synthesizing dyes and optical whitening agents.
