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Chemical Name: 1,2-Diphenylhydrazine
Other Names: Benzene, 1,1'-hydrazine; Hydrazobenzene
CAS Number: 122-66-7
Use Profile: Often brought into industrial labs for dye manufacture, pharmaceutical work, research, and some plastics applications. Several workers and lab users come across this in bench syntheses and quality control runs. Knowing what it looks like and where it turns up helps people spot exposures early.
Hazard Class: Acute toxin, environmental hazard, possible carcinogen
Exposure Routes: Can enter through inhalation, skin, and eye contact
Symptoms: Dizziness, vomiting, confusion, headache, skin or eye irritation, blue-tinted lips and fingers as a sign of lowered blood oxygen
Targets: Central nervous system, liver, kidneys, blood
Long-Term Risks: Evidence points to cancer risk when inhaled or absorbed over time. Chronic exposure may also reduce red blood cell counts.
Main Contents: Pure 1,2-Diphenylhydrazine by weight—usually encountered above 95% concentration in labs
Impurities: Trace amounts of benzidine-related compounds may appear due to production methods, and these raise health concerns.
Molecular Formula: C12H12N2
Inhalation: Move person into fresh air. Offer oxygen if breathing feels difficult. Maintain open airway. Medical evaluation is necessary anytime symptoms appear.
Skin Contact: Take off any contaminated clothing fully. Rinse skin with lots of water and gentle soap, scrubbing affected parts for several minutes.
Eye Contact: Hold eyelids wide and gently flush eyes with clean water for many minutes, aiming for at least ten. Get prompt medical care if discomfort continues.
Ingestion: Avoid inducing vomiting. Have the exposed person rinse their mouth with water. The exposed individual should get medical evaluation for ingestion, especially if clamps of confusion or spoon-shaped nails show up later.
Extinguishing Media: Dry chemical, CO2, and foam stand out as top choices. Water spray works for cooling but spreading of compound can occur if not cautious.
Fire Hazards: Under fire, this compound can give off nitrogen oxides and carbon monoxide—breathing these even for a few minutes may threaten health.
Protective Gear: Firefighters absolutely need self-contained breathing equipment and chemical-protective suits.
Clean-Up Steps: Evacuate unnecessary people. Workers need gloves, face shield, chemical goggles, and approved respirators. Scoop up and collect all solid or spilled material, place in secure containers.
Spill Control: Meant for contained, ventilated areas. Avoid dust—moisten the area with water if the chemical is in powder form. All waste generated demands labeling and disposal as hazardous waste.
Handling: Always use chemical fume hoods or proper ventilation. Laboratory users should wear long-sleeve coats and gloves. Never eat, drink, or smoke anywhere near the workspace, since accidental transfers from gloves to food cause many unreported exposures.
Storage: Keep containers tightly closed, in dry, cool, locked locations far from acids, oxidizers, or sunlight.
Engineering Controls: Local exhaust ventilation minimizes airborne particles. Closed systems help, but splash guards and eyewash stations boost safety.
Personal Protective Equipment: Nitrile or neoprene gloves, lab coats, closed shoes, safety goggles, and, for larger amounts, a full-face respirator with organic vapor cartridges.
Exposure Limits: Regulatory agencies including OSHA and NIOSH flag almost all forms as hazardous, yet specific limits for 1,2-Diphenylhydrazine might not be published everywhere. Handle as “potential human carcinogen.”
Appearance: White to pale yellow crystals with faint, mild odor
Melting Point: Close to 124 °C
Boiling Point: Data show variable readings, usually about 310 °C at atmospheric pressure
Solubility: Most organic solvents, low in water
Vapor Pressure: Low, but can become volatile if heated above room temperature
Density: 1.17 g/cm³
Chemical Stability: Stable in closed containers kept cool and dry. Exposure to light and air causes darkening and breakdown.
Incompatible Materials: Strong acids, oxidizing agents, and metals like iron or copper speed up decomposition.
Hazardous Reactions: Prolonged contact with moist air or sunlight leads to formation of nitrogen oxides and toxic breakdown products.
Acute Effects: Skin or eye contact brings pain, redness, and lasting irritation. Swallowing or breathing it in causes nausea, headaches, dizziness, and methemoglobinemia, which robs the blood of oxygen-carrying strength.
Carcinogenicity: International Agency for Research on Cancer (IARC) places 1,2-diphenylhydrazine on a list of possibly cancer-causing chemicals based on animal lab tests.
Chronic Exposure: Repeated exposure often leaves users with anemia, liver problems, and chronic tiredness. Nerve impairment also appears if mishandled
Other Hazards: Sensitization may occur—chronic skin exposures make some employees more likely to react strongly to even very slight doses the next time around.
Aquatic Toxicity: Proven toxic to aquatic life, especially fish and invertebrates, even in low levels. Spills into drains find their way into waterways where traditional sewage systems don’t filter it completely.
Persistence: Compound resists breakdown in nature, lingering in sediment and water for an extended time.
Bioaccumulation: Laboratory data show buildup in aquatic species over time—potentially climbing the food chain.
Recommendations: Always prevent entry into soil, water, or public drainage.
Waste Disposal: Follow strict hazardous waste protocols—never pour down the drain or toss in the trash. Specialized chemical waste firms treat and burn it at high temperatures to destroy residues.
Container Disposal: Empty, rinsed containers must carry hazard labels. Cleaning residues may still create exposure risks for custodial and transport staff.
Shipping Regulations: Most transport rules place it under restricted substances lists. Packages need solid outer packaging and clear hazard markings for both ground and air freight.
Hazard Class: Generally shipped as a toxic solid—extra paperwork applies for international shipments.
Incident Precautions: Trained personnel must handle any leakage or rupture since the powder easily contacts skin and spreads in the air.
Global Status: Listed on several hazardous substance inventories, including those run by OSHA, EPA, and European regulatory bodies.
Restrictive Uses: Regulations may force companies to report and limit the amount on hand, especially near waterways, schools, or laboratories not registered for hazardous handling.
Worker Protections: Laws require chemical hygiene plans, ready access to safety data, and specific training for those who could inhale or touch the compound in any form.
