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Chemical Name: Cyclobutane
Chemical Formula: C4H8
Synonyms: Tetramethylene
Appearance: Colorless gas under normal room temperature and pressure, can be condensed to a liquid at lower temperatures
Odor: Faint, gasoline-like
Common Uses: Laboratory research, synthetic organic chemistry, study of photochemical reactions
CAS Number: 287-23-0
Hazard Class: Flammable gas
Primary Hazards: High flammability, risk of explosion if mixed with air
Acute Symptoms: Inhalation may cause dizziness, headache, and central nervous system depression; prolonged exposure to high concentrations can lead to loss of consciousness
Chronic Risks: Insufficient human data for chronic health effects; animal studies focus on asphyxiation risks and respiratory irritation
NFPA Ratings: Health: 1, Flammability: 4, Reactivity: 2
GHS Signaling: Exploding bomb and flame pictograms mark serious fire and explosion risk
Main Component: Cyclobutane (C4H8), ≥99% by weight
Impurities: Trace hydrocarbons, ethylene, propylene—level depends on source and purification
No additional additives included in research-grade material
Inhalation: Move the affected person to fresh air as quickly as possible; assist breathing with oxygen if available; seek medical attention immediately if symptoms persist or worsen
Skin Contact: In case of contact with rapidly boiling liquid form, flush area with lukewarm water; do not attempt to remove clothing frozen to skin; seek medical attention for frostbite
Eye Contact: Rinse eyes with plenty of water for several minutes; medical attention required if irritation or injury occurs
Ingestion: Unlikely due to gaseous state at room temperature, but if exposure occurs by accident, get prompt medical help
Symptoms to Watch: Disorientation, headache, nausea, or trouble breathing can indicate overexposure
Suitable Extinguishing Methods: Use dry chemical, CO2, or foam on small fires; large fires may call for water spray to control vapor but not to extinguish flames directly
Specific Hazards: Extremely flammable gas; explosion risk in enclosed or poorly ventilated spaces; container rupture possible under fire conditions
Protective Equipment for Firefighters: Self-contained breathing apparatus and full protective gear required
Combustion Products: May include carbon monoxide and carbon dioxide
Containment Approach: If possible to do so safely, stop the flow of product; evacuate the area, and cool containers exposed to flame with water spray from a safe distance to avoid rupture
Personal Precautions: Evacuate nonessential personnel, remove all ignition sources, ventilate the area
Containment: Shut off the leak if it can be done without personal risk; do not attempt to enter a confined space without proper gear
Mitigation: Use explosion-proof ventilating systems; land spills typically require isolation from sewers and drains
Environmental Measures: Prevent entry into water systems, sewers, or confined areas where vapors can accumulate
Cleanup Methods: Disperse gas with ample ventilation, monitor atmosphere with explosion meters
Safe Handling: Work in well-ventilated spaces; avoid all sources of ignition, sparks, or open flames
Protective Practices: Only discharge compressed gas cylinders using proper regulators and never leave open lines unattended
Storage Conditions: Keep containers tightly closed; store in cool, dry, ventilated areas designed for flammable gases; ground and bond containers and equipment
Incompatible Materials: Strong oxidizers, open flames, hot surfaces, sources of static electricity
Cylinder Handling: Secure upright to prevent tipping; keep away from heat and direct sunlight
Exposure Limits: No specific OSHA or ACGIH exposure limits for cyclobutane, but similar precautions as with other flammable gases apply
Engineering Controls: Exhaust ventilation and gas detection alarms in labs or storage areas
Personal Protection: Use approved respirators if concentrations rise above safe levels and adequate ventilation is not possible; protective gloves and safety goggles recommended; flame-resistant lab coats may be required in some workspaces
Hygiene Measures: Wash exposed skin thoroughly after handling; avoid eating or drinking in work areas
Physical State: Gas at room temperature, can condense to liquid under pressure or low temperature
Boiling Point: -6.5°C
Melting Point: -91°C
Density (Gas): Lighter than air
Vapor Pressure: High; readily forms flammable mixtures with air
Solubility: Insoluble in water, but soluble in organic solvents
Odor Threshold: Low; faint, resembles gasoline
Flash Point: Well below 0°C
Autoignition Temperature: About 415–465°C
Flammable Limits in Air: Lower limit ~2%, upper limit ~10%
Chemical Stability: Maintains stability under recommended handling and storage; unstable in presence of strong oxidizers
Hazardous Reactions: Violent reactions possible with oxidizing agents, may decompose violently at high temperature or under strong UV light
Avoid Conditions: Heat, flames, sparks, static discharge, strong oxidizing chemicals
Decomposition Products: Mainly carbon monoxide and carbon dioxide, additional hydrocarbons may form in case of incomplete combustion
Routes of Exposure: Inhalation is the main risk for humans
Immediate Effects: Central nervous system depression, dizziness, headache, nausea, and at very high concentrations, risk of fainting or suffocation
Skin and Eye Contact: Cryogenic liquid form can cause frostbite; gas form unlikely to irritate skin or eyes at reasonable concentrations
Long-Term Risks: No evidence links chronic exposure to significant long-term toxic effects at low concentrations
Animal Studies: Most data suggest low acute toxicity, with effects mainly tied to asphyxiation due to oxygen displacement
Biodegradability: Not readily biodegradable, but rapid atmospheric dispersion reduces risk of environmental build-up
Aquatic Toxicity: Unlikely to cause direct harm due to low solubility and volatility; indirect impact possible through oxygen displacement in closed or waterlogged environments
Persistence: Short atmospheric lifetime, quickly broken down by natural processes
Bioaccumulation: No tendency to build up in living tissue reported so far
Safe Disposal: Vent unwanted gas to an appropriate, well-ventilated stack away from ignition sources; do not vent inside buildings or sealed containers
Regulatory Compliance: Follow federal, state, and local regulations for gaseous hydrocarbon disposal; empty cylinders require proper purging before recycling or disposal
Do Not: Attempt disposal by pouring into drains, surface water, or landfill
Environmental Precaution: Prevent venting into closed or inhabited spaces to avoid asphyxiation risk
Proper Shipping Name: Cyclobutane, compressed gas
Transport Hazard Class: Flammable Gas
UN Number: UN2601
Packing Group: Not assigned
Labeling: Flammable gas labels required on cylinders
Regulatory Status: Subject to specific handling and transport rules under the UN Recommendations for the Transport of Dangerous Goods, US DOT, and similar jurisdictions
Precautions: Only trained personnel should handle or move cylinders, keep secured and upright, avoid impact
Global Regulations: Cyclobutane falls under major hazardous chemical lists due to its flammability
US EPA: Not specifically listed for reportable quantities, but regulated by general requirements for flammable gases
OSHA: Workplace storage and handling rules for flammable compressed gases apply
EU REACH: Registration required for quantities exceeding regulatory thresholds
TSCA: Appears on the US TSCA inventory as a recognized chemical substance
