Cyclopentene Chemical Properties
- Melting point:
- −135 °C(lit.)
- Boiling point:
- 44-46 °C(lit.)
- 0.771 g/mL at 25 °C(lit.)
- vapor pressure
- 20.89 psi ( 55 °C)
- refractive index
- Flash point:
- <−30 °F
- storage temp.
- water: soluble0.535g/L at 25°C
- Water Solubility
- Air Sensitive
- Henry's Law Constant
- 6.3 x 10-2 atm?m3/mol at 25 °C (Hine and Mookerjee, 1975)
- Stable. Highly flammable. Incompatible with strong oxidizing agents. Store cold.
- CAS DataBase Reference
- 142-29-0(CAS DataBase Reference)
- NIST Chemistry Reference
- EPA Substance Registry System
- Cyclopentene (142-29-0)
- Hazard Codes
- Risk Statements
- Safety Statements
- UN 2246 3/PG 2
- WGK Germany
- Autoignition Temperature
- 743 °F
- HS Code
- Acute oral LD50 for rats is 1,656 mg/kg (quoted, RTECS, 1985).
Cyclopentene Usage And Synthesis
colourless liquid with a petrol-like odour
Cyclopentene is a highly flammable liquid with a low flash point. It reacts readily with oxidizing agents.
Clear, colorless, watery, very flammable liquid with a characteristic sweet, petroleum-like odor.
Acute Toxicity. The oral LD50 in the rat is
1656 mL/kg, and the dermal LD50 in the rabbit is
1231 mL/kg. Inhalation of the concentrated vapor was lethal
to rats in 5min, and a 4 h exposure to 16,000 ppm was lethal
to four of six rats.
Chronic and Subchronic Toxicity. Chronic exposure of rats to 112–1139 ppm for 12 weeks showed no effects, whereas 8110 ppm for 6 h/day, 5 days/week for 3 weeks resulted in decreased body weight gains of female rats.
General Information. Short-term exposure of cyclopentene to humans revealed a tolerable level of only 10–15 ppm.
Cross-linking agent; organic synthesis; solvent; extracting agent.
Cyclopentene is present in coal tar, cigarette smoke, and automobile emissions. It is also detected in air close to forests and as a decomposition product of polypropylene. It is used as a raw material in chemical synthesis.
ChEBI: A cycloalkene that is cyclopentane having one endocyclic double bond.
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.
Air & Water Reactions
Highly flammable. Insoluble in water.
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.
May be harmful by inhalation, ingestion, or skin absorption. May cause eye and skin irritation.
Special Hazards of Combustion Products: Vapor may travel considerable distance to a source of ignition and flashback. Explosion may occur under fire condition.
Moderately toxic by ingestion and skin contact. A very dangerous fire hazard when exposed to flame or heat; can react with oxidning materials. Keep away from heat and open flame. To fight fire, use foam, CO2, dry chemical.
Schauer et al. (2001) measured organic compound emission rates for volatile organic
compounds, gas-phase semi-volatile organic compounds, and particle-phase organic compounds
from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission
rate of cyclopentene was 7.8 mg/kg of pine burned. Emission rates of cyclopentene were not
measured during the combustion of oak and eucalyptus.
California Phase II reformulated gasoline contained cyclopentene at a concentration of 1,120 mg/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 480 and 31,700 μg/km, respectively (Schauer et al., 2002).
Given that cyclopentene is prepared from cyclohepentanol, the latter may be present as an impurity.
Biological. Cyclopentene may be oxidized by microbes to cyclopentanol, which may oxidize to
cyclopentanone (Dugan, 1972).
Photolytic. The following rate constants were reported for the reaction of cyclopentene with OH radicals in the atmosphere: 6.39 x 10-11 cm3/molecule?sec (Atkinson et al., 1983), 4.99 x 10-11 cm3/molecule?sec at 298 K (Rogers, 1989), 4.0 x 10-10 cm3/molecule?sec (Atkinson, 1990) and 6.70 x 10-11 cm3/molecule?sec (Sablji? and Güsten, 1990); with ozone in the atmosphere: 8.13 x 10-16 at 298 K (Japar et al., 1974) and 9.69 x 10-16 cm3/molecule?sec at 294 K (Adeniji et al., 1981); with NO3 in the atmosphere: 4.6 x 10-13 cm3/molecule?sec at 298 K (Atkinson, 1990) and 5.81 x 10-13 cm3/molecule?sec at 298 K (Sablji? and Güsten, 1990).
Chemical/Physical. Gaseous products formed from the reaction of cyclopentene with ozone were (% yield): formic acid, carbon monoxide, carbon dioxide, ethylene , formaldehyde, and butanal. Particulate products identified include succinic acid, glutaraldehyde, 5-oxopentanoic acid, and glutaric acid (Hatakeyama et al., 1987).
At elevated temperatures, rupture of the C-C bond occurs forming molecular hydrogen and cyclopentadiene (95% yield) as the principal products (Rice and Murphy, 1942).
Free cyclopentene from hydroperoxide by refluxing with cupric stearate. Fractionally distil it from Na. It can be chromatographed on a Dowex 710-Chromosorb W GLC column. Methods for cyclohexene should be applicable here. Also, it has been washed with 1M NaOH solution followed by water. It was dried over anhydrous Na2SO4, distilled over powdered NaOH under nitrogen, and passed through neutral alumina before use [Woon et al. J Am Chem Soc 108 7990 1986]. It was distilled in a dry nitrogen atmosphere from powdered fused NaOH through a Vigreux column (p 11), and then passed through activated neutral alumina before use [Wong et al. J Am Chem Soc 109 3428 1987]. [Beilstein 5 IV 209.]
Cyclopentene Preparation Products And Raw materials
- Cyclopentyl chloride
- 2-CYCLOPENTEN-1-YL ETHER, 98
- 5-Norbornene-2,3-dicarboxylic acid
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