Cyclopentadiene

Other Classes -> Aliphatics, Unsaturated

Flammable agents - 3rd degree

MONOMERIC FORM HAS TERPENE ODOR IN VAPOR STATE

Irritating terpene-like odor

0.8 (NIOSH, 2024) - Less dense than water; will float

0.8021 g/cu cm at 20 °C

Relative density (water = 1): 0.8

0.80

0.80

Insoluble (NIOSH, 2024)

In water, 1,800 mg/L at 25 °C

Miscible with carbon tetrachloride; soluble in carbon disulfide, aniline, acetic acid, liquid petrolatum

Soluble in acetone; miscible with ethanol, ethyl ether, benzene

Solubility in water: insoluble

Insoluble

77 °F (NIOSH, 2024)

77 °F

77 °F (OPEN CUP)

-20 °C

77 °F (open cup)

(oc) 77 °F

107 °F at 760 mmHg (NIOSH, 2024)

41 °C

41.5-42.0 °C

107 °F

107 °F

When heated to decomposition it emits acrid smoke and irritating fumes.

It decomposes violently at high temperatures and pressures.

-121 °F (NIOSH, 2024)

-95.54 °C

-85 °C

-121 °F

-121 °F

(AIR= 1) AT BOILING POINT OF CYCLOPENTADIENE 2.3

Relative vapor density (air = 1): 2.3

Odor Threshold Low: 1.8 [ppm]

Low Threshold= 5.0 mg/cu m; High threshold= 5.0 mg/cu m.

Danger

H225 (28.2%): Highly Flammable liquid and vapor [Danger Flammable liquids]

P210, P233, P240, P241, P242, P243, P261, P262, P264, P264+P265, P270, P271, P280, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P316, P317, P319, P321, P330, P332+P317, P337+P317, P361+P364, P362+P364, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 372 reports by companies from 9 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Danger

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

Chemical: 1,3-Cyclopentadiene

1,3-Cyclopentadiene is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of 1,3-Cyclopentadiene are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

SP - indicates a substance that is identified in a proposed Significant New Use Rule.

Status: Active Update: 27-04-2023 https://echa.europa.eu/registration-dossier/-/registered-dossier/34854

Cyclopentadiene: Does not have an individual approval but may be used under an appropriate group standard

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

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

Flammable. Above 25 °C explosive vapour/air mixtures may be formed. Risk of fire and explosion on contact with incompatible substances. See Chemical Dangers.

Cyclopentadiene causes narcosis and liver injury in animal experiments. It has an irritating odor that is objectionable to workers. [ACGIH, 1987] A skin, eye, and respiratory tract irritant; [ICSC]TLV and Documentation withdrawn; . . . Since cyclopentadiene (CPD) dimerizes into DCPD [Dicyclopentadiene], we recommended using the TLV for DCPD if CPD is of concern. There is little information available on the toxicity of CPD. [ACGIH, 2019] See Dicyclopentadiene.

Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, exposure, and use to EPA as cited in the preamble in 51 FR 41329. Effective date: 8/4/95; Reporting date: 10/3/95.

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Cyclopentadiene is included on this list. Effective date: 8/4/95; Sunset date: 6/30/98.

CYCLOPENTADIENE is incompatible with strong oxidizing agents. Ignites on contact with oxygen (O2) and ozone (O3). Explodes on contact with fuming nitric acid or a mixture of sulfuric acid and nitrogen tetroxide. Reacts vigorously on contact with potassium hydroxide and other strong bases. Mixtures with air are explosive. Presents a moderate explosion hazard when exposed to heat or flame. Decomposes violently at high temperature and pressure. May form explosive peroxides in storage. Undergoes a spontaneous dimerization at room temperature to give DICYCLOPENTADIENE (C10H12, CAS No: 77-73-6), which is a low-melting solid (melting point: 32.5 °C). The reaction is strongly exothermic (Hazardous Chemicals Desk Reference, p. 360 (1987)), but occurs sufficiently slowly that cyclopentadiene can be said to be stable at room temperature. The dimerization accounts for the partial or complete solidification of liquid cyclopentadiene in storage. Polymerization occurs more rapidly and extensively at higher temperatures. When heated to 180-200 °C, cyclopentadiene gives polycyclopentadiene, a white waxy solid. Stronger heating breaks down polycyclopentadiene and re-generates the monomeric cyclopentadiene as a vapor. The vapor decomposes violently at higher temperatures and pressures.

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

Use powder, foam, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Seek medical attention if you feel unwell.

Excerpt from NIOSH Pocket Guide for Cyclopentadiene:

(General first aid procedures)

Powder, aqueous film-forming foams (AFFF), foam, carbon dioxide ... Keep drums, etc, cool by spraying with water.

Dry chemical, carbon dioxide, foam

A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20 °C.

Fireproof. Separated from strong oxidants, strong acids, potassium hydroxide. Cooled. Store only if stabilized.

Monomer may largely be prevented from dimerizing by storage at -80 °C or below.

Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent and remove to safe place (extra personal protection: self-contained breathing apparatus).

1. Remove ... ignition sources. 2. Ventilate area of spill. ... 3. For small quantity, allow material to dimerize, collect on paper or other material. Evaporate in safe place (such as fume hood). Allow sufficient time for evaporating vapors to completely clear hood ductwork. Burn paper in suitable location. ... 3. Large quantities may be reclaimed or dissolved in appropriate solvent & atomized in suitable combustion chamber. ... Should not be allowed to enter confined space, such as sewer, because of possibility of an explosion.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Incineration

Evacuate danger area! Remove all ignition sources. Consult an expert! Personal protection: self-contained breathing apparatus. Collect leaking liquid in sealable containers. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

SRP: Contaminated protective clothing should be segregated in a manner such that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. The completeness of the cleaning procedures should be considered before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at the end of shift, but should remain at employee's place of work for cleaning.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.

The worker should immediately wash the skin when it becomes contaminated.

For more Preventive Measures (Complete) data for 1,3-CYCLOPENTADIENE (7 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 80(SRC), determined from a structure estimation method(2), indicates that 1,3-cyclopentadiene is expected to have high mobility in soil(SRC). Volatilization of 1,3-cyclopentadiene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 2.1X10-2 atm-cu m/mole(SRC), based upon its vapor pressure, 435 mm Hg(3), and water solubility, 1800 mg/L(4). 1,3-Cyclopentadiene is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). Biodegradation data in soil were not available(SRC, 2014).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 80(SRC), determined from a structure estimation method(2), indicates that 1,3-cyclopentadiene is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 2.1X10-2 atm-cu m/mole(SRC), derived from its vapor pressure, 435 mm Hg(4), and water solubility, 1800 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 2.4 hours and 3.2 days, respectively(SRC). Olefins, as a general class, are susceptible to reaction with photochemically-produced hydroxyl radicals and singlet oxygen in natural waters(6). Half-lives are typically on the order of 13-14 days for olefins reacting with hydroxyl radicals and 40 days for cyclic olefins reacting with singlet oxygen(6). According to a classification scheme(7), an estimated BCF of 14(SRC), from an estimated log Kow of 2.25(2) and a regression-derived equation(2), suggests the potential for bioconcentration in aquatic organisms is low(SRC). 1,3-Cyclopentadiene is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(3). Biodegradation data in water were not available(SRC, 2014).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,3-cyclopentadiene, which has a vapor pressure of 435 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,3-cyclopentadiene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 2.5 hours(SRC), calculated from its rate constant of 1.4X10-10 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Vapor-phase 1,3-cyclopentadiene is also degraded by reaction with ozone(SRC); the half-life for this reaction is estimated to be 52 minutes(SRC), calculated from its rate constant of 3.2X10-16 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Reaction of 1,3-cyclopentadiene with nitrate radicals in the night time atmosphere may also be a relevant removal mechanism(4).

The substance can be absorbed into the body by inhalation.

inhalation, ingestion, skin and/or eye contact

IDENTIFICATION AND USE: 1,3-Cyclopentadiene is a colorless liquid with an unpleasant odor. It is used as a starter compound in the manufacturing of resins and in organic synthesis as a starting material for synthetic prostaglandins, chlorinated insecticides, and formation of sandwich compounds by chelation. HUMAN EXPOSURE AND TOXICITY: Human exposure may occur during the manufacturing process. Short term exposure: exposure can irritate the eyes, skin, and respiratory tract. Skin contact causes a burning sensation and rash. Long term exposure: exposure may damage the liver and kidneys. Exposure can cause a skin allergy to develop. If allergy develops, even low exposures may cause symptoms. No further human studies could be located. ANIMAL STUDIES: Exposure to 1,3-Cyclopentadiene vapors produce CNS depression in the frog in 10 minutes, with a complete recovery in 70 minutes. In rats, 35 repeated daily 7-hour exposures to cyclopentadiene during a period of 53 days at an average concentration of 500 ppm resulted in mild injury to both liver and kidneys described as centrilobular, cloudy swelling of liver cells and cloudy vacuolization of renal tubular epithelium. In contrast, repeated daily exposures at 250 ppm produced no effects in rabbits, rats, guinea pigs, and dogs. In rabbits, subcutaneous injection of 3 cc was a CNS depressing dose with fatal convulsions; however, injections of 0.5 to 1.0 cc did not induce CNS depression. Signs and symptoms during CNS depression included primary motor unrest and a decreased intermittent respiration rate prior to death. The liquid caused marked local irritation, exudates in the pleural and peritoneal cavities, and hyperemia of the kidneys.

Cough. Sore throat.

Redness.

Redness. Pain.

Nausea. Vomiting.

irritation eyes, nose

1,3-Cyclopentadiene was detected in the concentration range of 10-100 ug/L, in one out of 63 effluents from US industries(1). 1,3-Cyclopentadiene has been detected in stack emissions from waste incineration(2), and in emissions from polymer manufacture, polymer combustion, and biomass combustion(3). 1,3-Cyclopentadiene was reported in the atmosphere near an oil fire at 0.061 mg/cu m(4). Median concentrations in fireplace smoke of 1,3-cyclopentadiene were measured in mg/kg dry fuel used: 29.39 from soft wood, 35.05 from hard wood and synthetic wood 0.93; and measured from hard wood burned in wood stoves at 80.90(5). In the production of vertically aligned multi-walled carbon nanotubes, 1,3-cyclopentadiene emissions from the pre-heat step were 4.7 ppmV at 690 °C to 17.6 ppmV at 1040 °C(6).

1,3-Cyclopentadiene emissions from three types of fuel were found at 0.003% in average gasoline, 0.002% in EPA certified gasoline and at 0% in 85% methanol gasoline(1). Four-stroke lawn mower studies showed 0.21% of total emissions where 1,3-cyclopentadiene with regular gasoline and 0.16% with reformulated gasoline(2). Single cylinder engines found 1,3-cyclopentadiene emissions present only when using 1-hexene fuel and a 50/50 by volume mixture of n-hexane/toluene for fuel(3). 1,3-Cyclopentadiene had an annual minimum emission from automobiles of 0.412 ppm from 5,094 vehicles and maximum of 1.206 ppm from 6,600 vehicles(4).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 1,3-cyclopentadiene can be estimated to be 80(SRC). According to a classification scheme(2), this estimated Koc value suggests that 1,3-cyclopentadiene is expected to have high mobility in soil.

/SIGNS AND SYMPTOMS/ Short Term Exposure: Exposure can irritate the eyes, skin, and respiratory tract. Skin contact causes a burning sensation and rash.

/SIGNS AND SYMPTOMS/ Human sensory response was distinctly unfavorable at both 250 and 500 ppm cyclopentadiene in terms of irritating, objectionable odor.

/SIGNS AND SYMPTOMS/ Long Term Exposure: Exposure may damage the liver and kidneys. Exposure can cause a skin allergy to develop. If allergy develops, even low exposures may cause symptoms.

1,3-Cyclopentadiene's production and use as a starting material for synthetic prostaglandins, for chlorinated insecticides, and the formation of sandwich compounds by chelation, for example, cyclopentadienyl iron dicarbonyl dimer(1), may result in its release to the environment through various waste streams(SRC).

Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, exposure, and use to EPA as cited in the preamble in 51 FR 41329. Effective date: 8/4/95; Reporting date: 10/3/95.

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Cyclopentadiene is included on this list. Effective date: 8/4/95; Sunset date: 6/30/98.

Routes of Entry: Inhalation, ingestion, skin and/or eye contact.

The substance can be absorbed into the body by inhalation.

Used in resin manufacturing and other organic syntheses; [ACGIH]

Manufacturing resins; in organic synthesis as the diene in Diels-Alder reaction producing sesquiterpenes, synthetic alkaloids, camphors.

Starting material for synthetic prostaglandins; chlorinated insecticides; formation of sandwich compounds by chelation, for example, cyclopentadienyl iron dicarbonyl dimer.

2023: 1,000,000 - <5,000,000 lb

(1984) 4.39X10+10 g

1,3-Cyclopentadiene is listed as a High Production Volume (HPV) chemical (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).

Production volumes for non-confidential chemicals reported under the Inventory Update Rule.[Table#3936]

Production volume for non-confidential chemicals reported under the 2006 Inventory Update Rule. Chemical: 1,3-Cyclopentadiene. Aggregated National Production Volume: 1 to < 10 million pounds.

Non-confidential 2014 Chemical Data Reporting (CDR) information on the production and use of chemicals manufactured or imported into the United States. Chemical: 1,3-Cyclopentadiene. National Production Volume: 510,714 lb/yr.

Obtained from the distillates produced in carbonization of coal, especially from the foreruns of coke-oven light oil; ... process involving the liquefaction of coke-oven gas; ... obtained during the cracking of petroleum hydrocarbons.

... The C5 fraction of pyrolysis gasoline contains ca. 25 wt% cyclopentadiene with approximately equal proportions of isoprene and of n-pentane, along with other C5 hydrocarbons. From the C5 fraction, cyclopentadiene can be isolated. ... In the first step, cyclopentadiene is dimerized to give dicyclopentadiene by heat soaking the entire C5 fraction, either at normal pressure and 30 - 100 °C over 5 - 24 hr or at elevated pressure and 140 - 150 °C. In the second step, the remaining components of the original C5 fraction, which have boiling points of 28 - 50 °C, are distilled overhead, and crude dicyclopentadiene (bp 172.8 °C) is obtained in 85 - 90% purity at the bottom of the column. In the third step, the crude dicyclopentadiene is monomerized, either in the liquid phase at 170 - 200 °C or in the gas phase at 300 - 400 °C in the presence of diluents such as steam, hydrogen, nitrogen, or methane, to give cyclopentadiene in ca. 95% purity. Cyclopentadiene can be further purified by sequential dimerizations under carefully controlled slow heat soaking and subsequent monomerizations. This procedure largely avoids the codimerization of cyclopentadiene with residual unsaturated C5 impurities, allowing the latter to be removed from dicyclopentadiene by stripping.

Petroleum Refineries

1,3-Cyclopentadiene: ACTIVE

/The dimer/ ... is a more convenient form in which to handle cyclopentadiene, and is easily depolymerized by distilling at atmospheric pressure. /Cyclopentadiene dimer/