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Chemical name: 1,3-Phenylenediamine
Synonyms: Meta-phenylenediamine, MPD
CAS number: 108-45-2
Appearance: Colorless to grey crystalline solid with a somewhat earthy odor
Molecular formula: C6H8N2
Odor threshold: No reliable data known, but the sharp distinctive smell tends to announce its presence quickly in an enclosed space
Acute toxicity: Exposure through skin contact, inhalation, or ingestion often leads to harmful effects. Skin and eye irritation show up fast, and allergic contact dermatitis is a significant risk for frequent handlers. Inhaling dust or vapor may result in headaches or respiratory distress. Red blood cells are at risk, as methemoglobinemia can sneak up and cause serious health complications. Long-term or high-level exposure has connections with kidney and liver damage, as well as lasting skin issues.
Hazard classification: Classified as hazardous for skin sensitization, acute toxicity, and environmental risk to aquatic life.
Signs and symptoms: Sensitization shows up as skin rash, itching, redness, swelling. Systemic symptoms include nausea, dizziness, blue-tinged skin from poor oxygenation.
Main component: 1,3-Phenylenediamine, no significant impurities known to reach hazardous thresholds in standard-grade product.
Chemical purity: Face-to-face with the raw stuff, purity usually lands above 97% in industrial supply, though minor nonhazardous byproducts sometimes sneak in after synthesis.
Inhalation: Move person to fresh air. Keep an eye on breathing. If symptoms like chest tightness or shortness of breath turn up, seek medical help right away.
Skin contact: Wash exposed area with soap and plenty of water. Remove any contaminated clothing, ensuring skin isn't exposed for long.
Eye contact: Flush eyes with water for at least 15 minutes, opening lids wide. If irritation or vision changes persist, medical attention is necessary.
Ingestion: Rinse mouth; never try to induce vomiting. Get medical care quickly. Activated charcoal may be given by professionals if significant exposure is suspected.
Most likely delayed effect: Methemoglobinemia, so medics need to know about the possibility of blue skin or low oxygen, and treatment with methylene blue may be required.
Suitable extinguishing media: Use foam, dry chemical powder, or CO2. Water spray helps cool surfaces but isn't the main extinguishing agent.
Hazards from combustion: Burning releases toxic gases, among them aniline, ammonia, nitrogen oxides, irritant smoke. Fire-fighters must gear up with full protective equipment and self-contained breathing apparatus.
Special hazards: Dust from the compound can create explosion risks in confined spaces. Rescuers should watch out for contaminated run-off that may enter water sources.
Personal precautions: Don protective gear, especially gloves, chemical goggles, and respirators if dust is present. People with asthma or allergies should stay clear.
Environmental precautions: Prevent run-off from entering soil or waterways. Even small spills can harm fish and aquatic organisms. Sand or soil barriers help contain spread.
Method for clean-up: Shovel spilled crystals into a suitable labeled container for disposal. Vacuuming with either a HEPA filter or wet methods can limit airborne dust.
Handling: Keep exposure low through careful handling. Always use gloves and eye protection, and limit how often bare skin touches work surfaces.
Storage: Store away from oxidizers and acids in a tightly closed, clearly labeled container. Dry, ventilated, and cool spaces work best, with secure access to keep unauthorized people safe.
Avoidance: Never eat, drink, or smoke around this substance. Wash hands after contact, and keep the chemical far from food or animal feed.
Engineering controls: Local exhaust ventilation removes dust and airborne vapors. Closed processing circuits or fume hoods offer reliable protection during weighing and mixing.
Personal protection: Nitrile gloves handle splashes or drips better than latex. Polycarbonate safety goggles keep the eyes protected. NIOSH-approved respirators with organic vapor cartridges protect the lungs if dust or vapor levels spike.
Hygiene measures: Never keep contaminated clothing on after finishing a job. Clean work areas daily, and avoid tracking powder into offices, lunchrooms, or homes.
Physical state: Solid, often a tan to greyish crystalline powder.
Odor: Faint, sometimes pungent.
Melting point: Around 63-64 °C.
Boiling point: Near 263 °C at atmospheric pressure.
Water solubility: Modest, dissolves in water but with effort.
Vapor pressure: Low under room conditions, so airborne concentration rises slowly except in heated environments.
Density: About 1.13 g/cm³.
Partition coefficient (log Kow): Roughly -1.42, showing moderate solubility in water and some mobility.
Stability under normal conditions: Doesn't break down fast at room temperature if kept dry and away from sunlight.
Conditions to avoid: Extreme heat, direct sunlight, open flames, and exposure to acids or oxidizers.
Incompatible materials: Powerful oxidizing agents and strong acids can trigger dangerous reactions.
Hazardous decomposition products: May break down into aniline, ammonia, nitrogen oxides, which all demand extra vigilance.
Acute effects: Short-term symptoms show up in the skin and blood, most notably allergic dermatitis and elevated methemoglobin levels. Small, repeated exposures snowball into bigger health issues for some workers.
Chronic effects: Extended or repeated skin exposure increases the chance of allergy development. Workplace studies have reported anemia, and organ damage at higher doses.
Routes of exposure: Skin, eyes, lungs, and gut—entry points depend on the job activity, like handling powders or cleaning spills.
Carcinogenicity: IARC doesn’t list it as a proven human carcinogen, but data stays limited.
Aquatic toxicity: Highly toxic to fish and aquatic invertebrates even at low concentrations. Once it's in the water, routine treatment plants struggle to fully remove it.
Persistence: Doesn’t break down quickly in the environment, and can build up in soil and water if spilled and not cleaned up.
Bioaccumulation: Quickly enters organisms, but does not seem to persist in tissues through food webs.
Soil mobility: Moderate movement possible, especially in light or sandy soils. Contamination risk stretches beyond the spill site if not confined early.
Methods: Dispose of as hazardous chemical waste through approved incineration or chemical treatment. Never dump down the drain or regular trash.
Packaging: Keep chemical waste in sealed, corrosion-resistant containers. Secure labels cut the risk of accidental mix-ups.
Local rules: Follow hazardous waste laws set by local and national authorities, which often demand notifications and specific paperwork.
UN number: 1673
Hazard class: Classified under classes related to toxic solids.
Packing group: Usually III, so the least strict group for acutely toxic substances, but incidents aren’t unheard of.
Environmental hazards: Marked as harmful due to spill risk in transit.
Precautions: Trucks, trains, or ships carrying it require warning stickers and controlled access, so handlers can catch leaks early.
Workplace limits: Some countries have specific exposure limits, but these vary and tend to be low. Occupational Safety and Health regulations often list phenylenediamine as a sensitizer.
Environmental controls: Manufacturing and use in large volumes triggers mandatory reporting and safety protocols by environmental agencies.
Labeling requirements: Labels must highlight health, sensitization, and aquatic toxicity risks with strong language and symbols.
Restrictions: Banned or strictly limited in cosmetic hair dyes and some consumer products in certain regions due to skin allergy risks.
