H-Acid (8-Amino-1-Naphthol-3,6-Disulfonic Acid)
CAS Number: 90-20-0
H-Acid is one of the most important naphthalene-based coupling components in the dye industry, used extensively in the synthesis of navy blue, black, and dark-shade reactive and direct azo dyes for cotton and wool. Its combination of amino, hydroxyl, and two sulfonic acid groups provides excellent coupling reactivity and contributes high wash fastness to finished dyes. Chemzip supplies H-Acid in both free acid and sodium salt forms to meet diverse formulation needs.
Technical Specifications
| appearance | Light brown to brown crystalline powder |
| purity (%) | ≥95.0 |
| insoluble matter (%) | ≤0.2 |
| sulfonic acid equivalent (%) | ≥40.0 |
Applications
- Navy blue and black reactive dye synthesis for cotton
- Direct dye intermediate for deep-shade cellulosic dyeing
- Acid dye coupling component for wool and nylon
- Chrome dye manufacturing for leather
- Mordant dye synthesis
Key Features
- Dual sulfonic acid groups ensure superior dye solubility and fiber affinity
- Consistent coupling capacity batch-to-batch for reproducible dye shades
- Available as free acid or sodium/potassium salt for process flexibility
- Manufactured under environmentally compliant processes meeting EU REACH
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CAS Number
90-20-0
Category
Dye / Pigment IntermediatesAvailability
In StockSample
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