| Name | Neutral Black BL |
| Synonyms | Acid Black 168 Neutral Black BL |
| CAS | 12238-87-8 |
| Use | Used for dyeing of wool, silk, tussah silk, nylon, vinylon, Wei/cotton, wool/viscose and other blended fabrics |
| Raw Materials | 4-Amino-3-hydroxy-1-naphthalenesulfonic acid N-(7-hydroxy-1-naphthyl)acetamide 2-Naphthol Salicylic acid Salicylic acid 2-Amino-4-nitrophenol |
1-amino -2-naphthol -4-sulfonic acid is oxidized with dilute nitric acid. due to the release of nitrogen dioxide, the pasty product is orange-yellow. saturated ammonium chloride solution is added to generate 1,2-naphthoquinone -4-ammonium sulfonate. Dissolve it in bromine-containing water and decolorize it with activated carbon, and then add saturated potassium chloride to precipitate potassium salt crystallization, with a yield of 17-18%.