English Safety Data Sheet Database 中文版 MSDS

cyclopentene

CAS No. 142-29-0 | PubChem CID 8882
Section 1. Identification
Chemical Namecyclopentene CAS No.142-29-0
Synonyms Chinese Name环戊烯
Molecular FormulaC5H8 Molecular Weight68.12547
UN No.2246 Data SourcePubChem (NIH/NLM)
GHS Hazard Classification
Signal Word DANGER
Pictograms GHS02 · Flammable GHS07 · Irritant GHS08 · Health Hazard
Hazard Statements H225H302H312H304H315H319H335H412H332
Precautionary Statements P210P233P240P241P242P243P261P264P264+P265P270P271P273P280P301+P316P301+P317P302+P352P303+P361+P353P304+P340P305+P351+P338P317P319P321P330P331P332+P317P337+P317P362+P364P370+P378P403+P233P403+P235P405P501

Section 2. Hazards Identification

H225 (100%): Highly Flammable liquid and vapor [Danger Flammable liquids]

H302+H312 (21.1%): Harmful if swallowed or in contact with skin [Warning Acute toxicity, oral; acute toxicity, dermal]

H302 (99.5%): Harmful if swallowed [Warning Acute toxicity, oral]

H304 (83.7%): May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H312 (100%): Harmful in contact with skin [Warning Acute toxicity, dermal]

H315 (93.7%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (13.2%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H335 (11.6%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H412 (14.7%): Harmful to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P270, P271, P273, P280, P301+P316, P301+P317, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P317, P319, P321, P330, P331, P332+P317, P337+P317, P362+P364, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 190 reports by companies from 12 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

H225: Highly Flammable liquid and vapor [Danger Flammable liquids]

H302: Harmful if swallowed [Warning Acute toxicity, oral]

H304: May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H312: Harmful in contact with skin [Warning Acute toxicity, dermal]

H315: Causes skin irritation [Warning Skin corrosion/irritation]

H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H332: Harmful if inhaled [Warning Acute toxicity, inhalation]

H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P270, P271, P280, P301+P316, P301+P317, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P317, P319, P321, P330, P331, P332+P317, P337+P317, P362+P364, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

P210, P233, P240, P241, P242, P243, P280, P303+P361+P353, P370+P378, P403+P235, and P501 (click each P-code to see the statement)

Section 4. First-Aid Measures

INHALATION: Call a physician. If inhaled, remove victim to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen.

EYES: Separate eyelids with finger. Flush with copious amounts of water for at least 15 minutes.

SKIN: Flush with water. (USCG, 1999)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

Specific First Aid:

· Wash skin with soap and water.

· In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

Section 5. Fire-Fighting Measures

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:

CAUTION: The majority of these products have a very low flash point. Use of water spray when fighting fire may be inefficient. CAUTION: For mixtures containing alcohol or polar solvent, alcohol-resistant foam may be more effective.

SMALL FIRE: Dry chemical, CO2, water spray or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam.

LARGE FIRE: Water spray, fog or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam. Avoid aiming straight or solid streams directly onto the product. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. For petroleum crude oil, do not spray water directly into a breached tank car. This can lead to a dangerous boil over. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

Section 6. Accidental Release Measures

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Ventilate closed spaces before entering, but only if properly trained and equipped.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· All equipment used when handling the product must be grounded.

· Do not touch or walk through spilled material.

· Stop leak if you can do it without risk.

· Prevent entry into waterways, sewers, basements or confined areas.

· A vapor-suppressing foam may be used to reduce vapors.

· Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers.

· Use clean, non-sparking tools to collect absorbed material.

Large Spill

· Dike far ahead of liquid spill for later disposal.

· Water spray may reduce vapor, but may not prevent ignition in closed spaces.

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 50 meters (150 feet) in all directions.

LARGE SPILL: Consider initial downwind evacuation for at least 300 meters (1000 feet).

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Immediate precautionary measure

· Isolate spill or leak area for at least 50 meters (150 feet) in all directions.

· Consider initial downwind evacuation for at least 300 meters (1000 feet).

· If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.

Section 7. Handling and Storage

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor-suppressing foam may be used to reduce vapors. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. Use clean, non-sparking tools to collect absorbed material.

LARGE SPILL: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor, but may not prevent ignition in closed spaces. (ERG, 2024)

Section 8. Exposure Controls / Personal Protection

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

CAUTION: The majority of these products have a very low flash point. Use of water spray when fighting fire may be inefficient.

CAUTION: For mixtures containing alcohol or polar solvent, alcohol-resistant foam may be more effective.

Small Fire

· Dry chemical, CO2, water spray or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam.

Large Fire

· Water spray, fog or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam.

· Avoid aiming straight or solid streams directly onto the product.

· If it can be done safely, move undamaged containers away from the area around the fire.

Fire Involving Tanks, Rail Tank Cars or Highway Tanks

· Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.

· Cool containers with flooding quantities of water until well after fire is out.

· For petroleum crude oil, do not spray water directly into a breached tank car. This can lead to a dangerous boil over.

· Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.

· ALWAYS stay away from tanks in direct contact with flames.

· For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn.

Self-contained breathing apparatus and protective clothing. (USCG, 1999)

Section 9. Physical and Chemical Properties

Cyclopentene appears as a colorless liquid. Less dense than water and insoluble in water. Flash point below 0 °F. Vapors heavier than air. Inhalation of high concentrations may be narcotic. Used to make rubber and plastics.

Colorless liquid; [CAMEO] Odor like gasoline; [FAHG] Slightly sweetish odor; [Alfa Aesar MSDS]

112 °F at 760 mmHg (USCG, 1999)

-211 °F (USCG, 1999)

-30 °F (USCG, 1999)

0.774 (USCG, 1999) - Less dense than water; will float

380.0 [mmHg]

Schoenflies notation

Acentric factor

Adsorbate coverage

Boiling point

Chemical bond

Composition

Critical point

Diamagnetic susceptibility

Diamagnetic susceptibility exaltation

Dielectric constant

Electric dipole moment

Exaltation data

Fusion temperature

Heat capacity

Heat of sublimation

Internuclear distance

Magnetic susceptibility

Magnetic susceptibility exaltation

Melting temperature

Molar mass

Molecular dipole moment

Molecular structure

Optical coefficient

Phase diagram

Phase transition

Point group

Refractive index

Rotational excitation cross section

Sound absorption

Sound propagation

Sound velocity

Surface tension

Thermal conductivity

Section 10. Stability and Reactivity

Highly flammable. Insoluble in water.

Hydrocarbons, Aliphatic Unsaturated

Polymerizable Compounds

Highly Flammable

Polymerizable

CYCLOPENTENE may react vigorously with strong oxidizing agents. May react exothermically with reducing agents to release hydrogen gas. In the presence of various catalysts (such as acids) or initiators, may undergo exothermic addition polymerization reactions.

Cyclopentene

B: Compounds that form peroxides on concentration (distillation/evaporation)

Section 11. Toxicological Information

Neurotoxin - Acute solvent syndrome

LCLo (rat) = 16,000 ppm/4hr

Section 14. Transport Information

Flammable Liquid

Source: PubChem CID 8882 (NIH/NLM, public domain). Retrieved from PubChem, a public-domain chemistry database maintained by the U.S. National Library of Medicine. Last updated: 2026-08-02 09:08:11.
Disclaimer: This information is compiled for reference only and does not replace the manufacturer's official Safety Data Sheet. Always consult the supplier's SDS before handling any chemical.