Acid Black 2 Powder
Acid Black 2 Powder is a synthetic anionic disazo dye belonging to the acid dye class, specifically formulated for intense black coloration with excellent light and wash fastness properties. This high-purity powder (100% active) exhibits superior solubility in aqueous solutions, making it particularly suitable for dyeing protein-based fibers like wool, silk, and nylon under acidic conditions. As a chromium-complex dye, it delivers enhanced color depth and improved fastness characteristics compared to non-metalized acid dyes. The powder form ensures precise dosing, consistent batch-to-batch reproducibility, and long-term stability when stored properly. Its molecular structure features sulfonic acid groups that facilitate strong ionic bonding with amino groups in fibers, resulting in vibrant, penetration-rich coloration with minimal bleeding.
1. Basic Identification Attributes
- Chemical Name (IUPAC):
Disodium 4-amino-5-hydroxy-3-[(4-nitrophenyl)azo]-6-(phenylazo)naphthalene-2,7-disulfonate - Common/Trade Names:
- Acid Black 2
- C.I. 50420
- Naphthalene Black 12B
- Eriochrome Black T (similar but distinct)
- CAS Number: [8005-03-6]
- HS Code: 3204.12.00 (acid dyes)
- Molecular Formula: C₂₂H₁₄N₆Na₂O₉S₂
- Molecular Weight: 616.5 g/mol
- Synonyms:
- Acid Black BN
- Lissamine Black 12B
- Wool Black 6BN
2. Physical & Chemical Properties
- Physical State: Fine powder
- Color: Dark bluish-black
- Odor: Odorless
- Melting Point: Decomposes before melting (~300°C)
- Boiling Point: Not applicable (decomposes)
- Density: ~1.5 g/cm³ (bulk density)
- Solubility:
- Water: 50 g/L (20°C)
- Ethanol: Slightly soluble
- Organic solvents: Insoluble
- pH Level: 5-7 (1% solution)
- Vapor Pressure: Negligible
- Flash Point: >200°C (non-flammable)
- Optical Properties: λmax = 570-620 nm (varies with pH)
3. Safety & Hazard Attributes
- Hazard Class (GHS):
- Acute Toxicity (Oral): Category 4 (H302)
- Skin Irritation: Category 2 (H315)
- Eye Irritation: Category 2A (H319)
- NFPA Ratings:
- Health: 2
- Flammability: 1
- Reactivity: 0
- Exposure Limits:
- OSHA PEL: Not established
- ACGIH TLV: Not established
- Reactivity:
- Stable under normal conditions
- Incompatible with strong oxidizers
4. Storage & Handling Attributes
- Storage Conditions:
- Cool, dry place (<30°C)
- Relative humidity <60%
- Away from direct sunlight
- Incompatible Materials:
- Strong oxidizers (peroxides, chlorates)
- Strong acids/bases
- Container Type:
- Sealed polyethylene or polypropylene containers
- Avoid metal containers
- Shelf Life: 24 months minimum
- Special Handling:
- Dust mask (NIOSH N95)
- Chemical-resistant gloves (nitrile)
- Eye protection (goggles)
5. Regulatory & Compliance Attributes
- Regulatory Status:
- EU: Compliant with REACH Annex XVII
- US: EPA TSCA listed
- China: IECSC listed
- Hazard Symbols (GHS):
- Exclamation mark (irritant)
- Not classified as carcinogenic
- Transportation Restrictions:
- Not regulated as dangerous goods
- Proper shipping name: "DYES, SOLID, N.O.S."
- Waste Disposal:
- Incineration at approved facilities
- Not RCRA hazardous (US)
6. Environmental & Health Impact
- Ecotoxicity:
- LC50 (fish): >100 mg/L (96h)
- EC50 (daphnia): >10 mg/L (48h)
- Persistence:
- Moderately biodegradable
- BOD5/COD: 0.1-0.3
- Carcinogenicity:
- IARC: Not classified
- NTP: Not listed
- Biodegradability:
- 30-60% in 28 days (OECD 301B)
Acid Black 2 Powder
Primary Uses
- Textile Dyeing
- Wool & Silk: Acid Black 2 is extensively used for dyeing protein-based fibers like wool, silk, and cashmere due to its strong affinity for these materials.
- Nylon & Synthetic Fibers: Also effective on polyamide (nylon) fabrics, providing deep, wash-fast black shades.
- Leather Industry: Used in leather dyeing for shoes, bags, and upholstery.
- Ink & Printing Industry
- Used in inks for ballpoint pens, stamp pads, and inkjet printing.
- Provides permanent, fade-resistant black coloration in specialty inks.
- Biological & Laboratory Staining
- Sometimes used in microscopy for staining biological specimens.
- Helps in histology for tissue contrast enhancement.
Secondary Uses
- Paper & Packaging Industry
- Used in colored paper production and security printing (e.g., banknotes, certificates).
- Cosmetics (Limited Use)
- Found in temporary hair dyes and cosmetic pigments (regulated for safety).
- Art & Craft Supplies
- Used in fabric paints, markers, and artist’s dyes for textiles.
- Wood Staining
- Occasionally applied in furniture and woodworking for dark finishes.
1. Safety Precautions
Personal Protective Equipment (PPE):
- Gloves: Nitrile or neoprene gloves
- Eye Protection: Chemical splash goggles
- Respiratory Protection: NIOSH-approved N95 mask or higher (for dust)
- Clothing: Lab coat or protective apron
Handling & Storage:
- Handle in a well-ventilated area or under a fume hood
- Avoid creating dust (use wet methods if possible)
- Keep away from oxidizers, strong acids, and bases
- Store in a cool, dry place in a tightly sealed container
- Label containers clearly
Hygiene Practices:
- Do not eat, drink, or smoke while handling
- Wash hands thoroughly after use
- Avoid inhalation of dust
2. First Aid Measures
Inhalation (Dust):
- Move to fresh air immediately
- If breathing is difficult, seek medical attention
Skin Contact:
- Remove contaminated clothing
- Wash affected area with soap and water for at least 15 minutes
- Seek medical attention if irritation persists
Eye Contact:
- Rinse eyes with plenty of water for at least 15 minutes (hold eyelids open)
- Seek immediate medical attention
Ingestion:
- Do NOT induce vomiting
- Rinse mouth with water
- Drink water to dilute
- Seek emergency medical help
3. Firefighting Measures
Fire Hazards:
- Not highly flammable, but may decompose at high temperatures
- May emit toxic fumes (NOx, CO, CO₂) when burning
Extinguishing Media:
- Water spray
- Dry chemical powder
- CO₂
- Foam
Firefighting Precautions:
- Wear self-contained breathing apparatus (SCBA)
- Cool containers exposed to fire with water spray
- Avoid breathing smoke/fumes
4. Spill & Disposal
Small Spills:
- Wear PPE
- Dampen with water to reduce dust
- Sweep up and place in a sealed container
Large Spills:
- Evacuate area
- Contain spill to prevent spread
- Collect for proper disposal
Disposal:
- Treat as hazardous waste
- Follow local regulations for dye disposal

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