Orange red powder, toxic; soluble in water, ethanol, alkali solution; an important azo dye intermediate, used in the synthesis of acid dyes, reactive dyes, direct dyes, suitable for dyeing cotton, wool, silk. Hazard Class: Class 6.1 dangerous goods; toxic.
Chinese alias：对氨基偶氮苯-4-磺酸（PAABSA）
English alias：4-Aminoazobenzene-4'-sulfonic acid；p-Aminoazobenzene-p'-sulfonic acid
Core intermediate for azo dyes; used in the synthesis of acid dyes (such as Acid Red, Acid Orange), reactive dyes, direct dyes, suitable for dyeing cotton, wool, silk and other fibers, improve dye brightness and dyeing efficiency
| No. | Test Parameter | Premium Grade | Qualified Grade |
| 1 | Appearance | Light yellow crystalline powder | Light orange-yellow crystalline powder |
| 2 | Main content | ≥96.0% | ≥94.0% |
| 3 | Amino value | ≥95.0% | ≥93.0% |
| 4 | Water content | ≤1.0% | ≤2.0% |
| 5 | Alkali insoluble matter | ≤0.1% | ≤0.2% |
| 6 | Main single impurities (p-Aminoazobenzene, Sulfanilic acid, Aniline) | Each ≤0.3%, Total ≤0.8% | Each ≤0.5%, Total ≤1.2% |
| 7 | pH value | 5.0-7.0 | 4.5-7.5 |
Address: Block B, Interstellar Center, Yuhua District, Shijiazhuang City, Hebei Province
