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Chemical Name: 1,4-Cyclohexadiene
Chemical Formula: C6H8
Synonyms: para-Cyclohexadiene
Appearance: Colorless to light yellow liquid with a mild aromatic odor
Uses: Intermediate in organic synthesis, especially for the preparation of benzene derivatives and as a reducing agent in the laboratory
CAS Number: 628-41-1
GHS Classification: Flammable liquid, Acute toxicity (oral, inhalation, dermal), Skin and eye irritant
Signal Word: Danger
Hazard Statements: Highly flammable liquid and vapor; Causes skin and eye irritation; Harmful if swallowed or inhaled
Risk of Fire: Vapors may form explosive mixtures with air; Release of vapor indoors increases fire risk, especially without ventilation
Potential Health Effects: Shortness of breath, dizziness, headache from inhalation; Nausea or vomiting if swallowed; Redness, itching, or watering of eyes or skin on contact
Chronic Exposure: Frequent or prolonged exposure can dry or crack skin; Prolonged inhalation can harm central nervous system
Substance: 1,4-Cyclohexadiene
Purity: Usually exceeds 98% in commercial solutions
Impurities: Small amounts of benzene and other cyclohexadiene isomers may occur
Chemical Family: Unsaturated hydrocarbon
Inhalation: Move to fresh air; Keep person calm and warm; Seek medical attention if symptoms persist; Monitor for respiratory distress
Skin Contact: Remove contaminated clothing; Wash exposed skin thoroughly with soap and water; Seek medical advice for irritation
Eye Contact: Rinse cautiously under running water for at least 15 minutes; Lift eyelids; Seek medical attention immediately
Ingestion: Rinse mouth; Do not induce vomiting; Never give anything by mouth to an unconscious person; Seek immediate medical help
Suitable Extinguishing Media: Foam, dry chemical, carbon dioxide
Unsuitable Media: Water may spread fire, but useful for cooling containers
Special Hazards: Flammable vapors can travel some distance to ignition sources and flashback; Combustion releases toxic gases including carbon monoxide
Protective Equipment: Full firefighting gear, self-contained breathing apparatus; Remove containers from fire area if safe to do so
Advice for Firefighters: Use water spray to keep surfaces cool and prevent vaporization; Stay uprange to avoid inhalation
Personal Precautions: Evacuate area; Remove all ignition sources; Ventilate enclosed spaces; Avoid inhaling vapor
Protective Equipment: Wear chemical-resistant gloves, goggles, and protective clothing; Use respirators if adequate ventilation is unavailable
Spill Response: Contain spill with inert absorbents (earth, vermiculite); Collect residue in suitable chemical waste container; Avoid direct contact
Environmental Precautions: Prevent runoff to drains or waterways; Notify appropriate agencies if large amounts enter environment
Handling: Use only in well-ventilated settings; Ground and bond containers during transfer to avoid static discharge; Keep away from open flames, sparks, and heat sources; Avoid breathing vapors and direct contact with liquid
Storage: Store in tightly sealed containers made of compatible materials; Keep away from oxidizers, acids, and heat; Store in a cool, dry, well-ventilated place; Segregate from food and drink
Engineering Controls: Ventilation systems designed for flammable vapors; Fume hoods or explosion-proof exhaust preferred
Respiratory Protection: Use approved organic vapor respirators if ventilation inadequate
Hand Protection: Nitrile or neoprene gloves
Eye/Face Protection: Chemical splash goggles; Face shields for larger operations
Skin Protection: Long-sleeved chemical-resistant clothing and footwear
Exposure Limits: No OSHA PEL for 1,4-cyclohexadiene, but avoid exceeding 100 ppm for similar hydrocarbons as a precaution
Physical State: Liquid
Color: Colorless or slight yellow
Odor: Mildly aromatic
Boiling Point: 80 - 82°C
Melting Point: -98°C
Vapor Pressure: 35 mmHg at 25°C
S o l u b i l i t y: Insoluble in water; soluble in organic solvents
Flash Point: -1°C (closed cup)
Density: 0.866 g/cm³ at 20°C
Autoignition Temperature: 535°C
Explosion Limits: LEL approximately 1.3%; UEL approximately 7.8%
Chemical Stability: Stable under normal temperature and pressure in closed systems
Reactivity: May react with strong oxidizers, acids, and reactive halogens
Conditions to Avoid: Heat, sparks, open flame, exposure to air for prolonged periods
Hazardous Decomposition: Emits carbon monoxide, carbon dioxide, and irritating smoke when burned
Polymerization: Not known to polymerize under typical use
Acute Toxicity: Can cause respiratory tract, eye, and skin irritation; LD50 (oral, rat): ranges from 500 - 2000 mg/kg, depending on available studies
Inhalation: Causes drowsiness, dizziness, possible central nervous system depression at higher concentrations
Skin Sensitization: No strong evidence for skin sensitization, but repeated exposure dries out skin
Chronic Effects: Not classified as carcinogenic; Long-term exposure can affect liver and kidneys
Reproductive Toxicity: No strong evidence for reproductive harm in available literature
Environmental Fate: Volatile and prone to evaporating from soil or water surfaces; Biodegradation occurs but rate depends on temperature and presence of sunlight
Aquatic Toxicity: Harmful to aquatic life at elevated concentrations; Can cause fish and invertebrate mortality if released in large spills
Mobility in Soil: Low water solubility means low mobility; Most likely to volatilize into air rather than leach
Persistence and Bioaccumulation: Rapid evaporation and moderate biodegradation limit long-term persistence
Hazard to Environment: Avoid release into waterways, drains, or sewers
Waste Treatment Options: Incinerate in approved facility; Chemical waste container for collection and disposal
Do Not: Dump in landfill or down household or industrial drains
Contaminated Packaging: Use professional chemical disposal; Rinse with solvent prior to recycling, if allowed by local regulation
UN Number: 1993 (for flammable liquid—organic, not otherwise specified)
Proper Shipping Name: Flammable Liquid, N.O.S. (1,4-Cyclohexadiene)
Hazard Class: 3 (Flammable liquids)
Packaging Group: II (medium hazard)
Precautions for Transport: Secure upright, protect from physical damage, mark with hazard labels; Do not ship with oxidizers; Keep away from heat sources in transit
U.S. Regulations: Listed under SARA Title III Section 311/312 (fire, acute health); Not specifically listed by name under CERCLA or RCRA; May be subject to reporting in large releases
International Notices: Included in major chemical inventories (TSCA, EINECS, DSL, AICS); Classified as Dangerous Goods for transport and storage
Workplace Classification: Flammable, harmful, and irritant substances in most national workplace safety laws
Precautionary Labeling: Proper hazard labeling required for all storage and transportation
