Cyclopentadiene

  • 1,3-Cyclopentadiene
  • Pyropentylene
  • Pentole
Formula C5H6
Structure
Description Colorless liquid. Monomeric form has terpene odor in vapor state.
Uses Manufacture resins, in organic synth as diene in diels-alder reaction producing sesquiterpenes, synthetic alkaloids, camphors.

Registry Numbers and Inventories.
CAS 542-92-7
EC (EINECS/ELINCS) 208-835-4
RTECS GY1000000
RTECS class Other
UN (DOT) 2371
Merck 12,2807
Beilstein/Gmelin 471171
Beilstein Reference 4-05-00-00377
Swiss Giftliste 1 G-1466
Canada DSL/NDSL DSL
US TSCA Listed
Austrailia AICS Listed
New Zealand Listed
Korea ECL Listed

Odor Threshold Odor threshold 5.0 mg/m3
Properties.
Formula C5H6
Formula mass 66.1
Melting point, °C -85
Boiling point, °C 42
Vapor pressure, mmHg 439 (25 C)
Density 0.8021 g/cm3 (20 C)
Solubility in water Insoluble
Refractive index 1.44632 (20 C)
Partition coefficient, pKow 1.89
Heat of vaporization 27.4 kJ/mol

Hazards and Protection.
Storage Monomer may largely be prevented from dimerizing by storage at -80C or below.
Handling All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection Wear appropriate eye protection and protective clothing to prevent skin and eye contact.
Respirators Wear positive pressure self-contained breathing apparatus (SCBA).
Small spills/leaks Make no contact with the spilled material. ELIMINATE all ignition sources and ground all equipment. Stop leak if you can do it without risk. 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.
Stability No data.
Incompatibilities Incompatible with nitric acid; oxides of nitrogen; oxygen; sulfuric acid. Contact with strong oxidizing agents may cause explosions. Avoid contact with strong oxidizers, fuming nitric acid, sulfuric acid.
Decomposition It decomposition violently @ high temp and pressure.

Fire.
Flash Point,°C -46
Autoignition, °C 640
Upper exp. limit, % 14.6
Lower exp. limit, % 1.7
Fire fighting Dry chemical, carbon dioxide, foam
Fire potential Moderate fire hazard, when exposed to heat or flame
Hazards Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers.
Combustion products Toxic gases and vapors (such as carbon monoxide) may be released in fire involving cyclopentadiene.
NFPA Health -
  Flammability 2  

Health.
Exposure limit(s) TLV (as TWA): 75 ppm; 203 mg/m3 (ACGIH 1995-1996). OSHA PEL: TWA 75 ppm (200 mg/m3) NIOSH REL: TWA 75 ppm (200 mg/m3) NIOSH IDLH: 750 ppm
Poison_Class 4
Exposure effects Mild central nervous system depression or excitation may occur after ingestion or vapor inhalation. CNS effects can occur secondary to hydrocarbon pneumonitis and hypoxia, or from additives and contaminants (aniline, heavy metals, camphor, or pesticides). Some hydrocarbons are simple asphyxiants (e.G., Methane, ethane, propane gasses) which can produce CNS effects secondary to hypoxia. In a prospective study in Toronto, major congenital malformations were noted in 13 of 125 fetuses of mothers exposed to organic solvents during pregnancy.
   Ingestion Nausea, vomiting, diarrhea, and abdominal pain may occur following ingestion.
   Inhalation Coughing, choking, tachypnea, dyspnea, cyanosis, rales, hemoptysis, pulmonary edema, pneumatoceles, lipoid pneumonia, or respiratory arrest may develop following ingestion and aspiration.
   Skin May cause irritation or burns.
   Eyes Redness, pain.

First aid
 
   Ingestion Pure petroleum distillates - gastric decontamination is not indicated in the majority of accidental ingestions, since systemic toxicity is unlikely from a pure petroleum distillate. Other hydrocarbons - gastric decontamination may be indicated if a large amount of a toxic hydrocarbon has been ingested (e.G., Suicide attempt) and if spontaneous vomiting has not occurred. Decontamination may also be indicated for ingestions of highly toxic hydrocarbons (e.G., Halogenated hydrocarbons, carbon tetrachloride) and for hydrocarbons which contain very toxic additives (e.G., Heavy metals, pesticides). The decision to decontaminate should be based on the toxicity of the agent, the volume ingested, time of ingestion and patient's clinical status. The potential for rapid cns depression, with seizures and/or respiratory depression, must be considered.
   Inhalation Move victim to fresh air. Apply artificial respiration if victim is not breathing. Administer oxygen if breathing is difficult.
   Skin Remove and isolate contaminated clothing and shoes. Wash skin with soap and water. Flush with running water for at least 20 minutes
   Eyes Irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist, the patient should be seen in a health care facility.

Transport.
UN number 2371
Response guide 128
Hazard class 3
Packing Group I  
USCG CHRIS Code CPD  
USCG Compatatibility Group 30 Olefins
IMO Chemical Code 17
IMO Pollution Category B
IMO Hazard code P