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Cyclopentadiene

PubChem CID
7612
Structure
Cyclopentadiene_small.png
Cyclopentadiene_3D_Structure.png
Molecular Formula
Synonyms
  • Cyclopentadiene
  • 1,3-CYCLOPENTADIENE
  • cyclopenta-1,3-diene
  • 542-92-7
  • Pyropentylene
Molecular Weight
66.10 g/mol
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Dates
  • Create:
    2004-09-16
  • Modify:
    2025-01-18
Description
Cyclopentadiene is a colorless liquid with an irritating, terpene-like odor. Bp: 42.5 °C; Flash point: 77 °F. Density: 0.805 g cm-3.
Cyclopentadiene is a cycloalkadiene.
Cyclopentadiene has been reported in Oryza sativa and Cymbopogon citratus with data available.
See also: Cyclopentadienyl radical (annotation moved to).

1 Structures

1.1 2D Structure

Chemical Structure Depiction
Cyclopentadiene.png

1.2 3D Conformer

1.3 Crystal Structures

COD records with this CID as component

2 Names and Identifiers

2.1 Computed Descriptors

2.1.1 IUPAC Name

cyclopenta-1,3-diene
Computed by Lexichem TK 2.7.0 (PubChem release 2021.10.14)

2.1.2 InChI

InChI=1S/C5H6/c1-2-4-5-3-1/h1-4H,5H2
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.3 InChIKey

ZSWFCLXCOIISFI-UHFFFAOYSA-N
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.4 SMILES

C1C=CC=C1
Computed by OEChem 2.3.0 (PubChem release 2024.12.12)

2.2 Molecular Formula

C5H6
Computed by PubChem 2.2 (PubChem release 2021.10.14)
C5H6

2.3 Other Identifiers

2.3.1 CAS

542-92-7
2143-53-5

2.3.3 Deprecated CAS

2351150-22-4, 26912-33-4
26912-33-4

2.3.4 European Community (EC) Number

2.3.5 UNII

2.3.6 UN Number

2.3.7 ChEBI ID

2.3.8 ChEMBL ID

2.3.9 DSSTox Substance ID

2.3.10 HMDB ID

2.3.11 ICSC Number

2.3.12 Metabolomics Workbench ID

2.3.13 Nikkaji Number

2.3.14 RTECS Number

2.3.15 Wikidata

2.3.16 Wikipedia

2.4 Synonyms

2.4.1 MeSH Entry Terms

  • Cyclopentadiene
  • Cyclopentadienes
  • Cyclopentane
  • Cyclopentanes
  • Cyclopentene
  • Cyclopentenes

2.4.2 Depositor-Supplied Synonyms

3 Chemical and Physical Properties

3.1 Computed Properties

Property Name
Molecular Weight
Property Value
66.10 g/mol
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
XLogP3
Property Value
1.8
Reference
Computed by XLogP3 3.0 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Donor Count
Property Value
0
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Acceptor Count
Property Value
0
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Rotatable Bond Count
Property Value
0
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Exact Mass
Property Value
66.0469501914 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Monoisotopic Mass
Property Value
66.0469501914 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Topological Polar Surface Area
Property Value
0 Ų
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Heavy Atom Count
Property Value
5
Reference
Computed by PubChem
Property Name
Formal Charge
Property Value
0
Reference
Computed by PubChem
Property Name
Complexity
Property Value
58.1
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Isotope Atom Count
Property Value
0
Reference
Computed by PubChem
Property Name
Defined Atom Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Undefined Atom Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Defined Bond Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Undefined Bond Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Covalently-Bonded Unit Count
Property Value
1
Reference
Computed by PubChem
Property Name
Compound Is Canonicalized
Property Value
Yes
Reference
Computed by PubChem (release 2021.10.14)

3.2 Experimental Properties

3.2.1 Physical Description

Cyclopentadiene is a colorless liquid with an irritating, terpene-like odor. Bp: 42.5 °C; Flash point: 77 °F. Density: 0.805 g cm-3.
Liquid
Colorless liquid with an irritating, terpene-like odor; [NIOSH]
COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.
Colorless liquid with an irritating, terpene-like odor.

3.2.2 Color / Form

Colorless liquid
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 362

3.2.3 Odor

MONOMERIC FORM HAS TERPENE ODOR IN VAPOR STATE
American Conference of Governmental Industrial Hygienists. Documentation of the Threshold Limit Values and Biological Exposure Indices. 5th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, 1986., p. 163
Irritating terpene-like odor
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)

3.2.4 Boiling Point

107 °F at 760 mmHg (NIOSH, 2024)
41 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 3-138
41.5-42.0 °C
107 °F

3.2.5 Melting Point

-121 °F (NIOSH, 2024)
-95.54 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 3-138
-85 °C
-121 °F

3.2.6 Flash Point

77 °F (NIOSH, 2024)
77 °F
77 °F (OPEN CUP)
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)
-20 °C
(oc) 77 °F

3.2.7 Solubility

Insoluble (NIOSH, 2024)
In water, 1,800 mg/L at 25 °C
Amoore JE, Hautala E; J Appl Toxicol 3: 272-90 (1983)
Miscible with carbon tetrachloride; soluble in carbon disulfide, aniline, acetic acid, liquid petrolatum
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 488
Soluble in acetone; miscible with ethanol, ethyl ether, benzene
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 3-138
Solubility in water: insoluble
Insoluble

3.2.8 Density

0.8 (NIOSH, 2024) - Less dense than water; will float
0.8021 g/cu cm at 20 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 3-138
Relative density (water = 1): 0.8
0.80

3.2.9 Vapor Density

(AIR= 1) AT BOILING POINT OF CYCLOPENTADIENE 2.3
Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981., p. 2
Relative vapor density (air = 1): 2.3

3.2.10 Vapor Pressure

400 mmHg (NIOSH, 2024)
435.0 [mmHg]
Vapor pressure, kPa at 20 °C: 45.1 (calculated)
400 mmHg

3.2.11 Autoignition Temperature

640 °C
Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981., p. 2

3.2.12 Decomposition

When heated to decomposition it emits acrid smoke and irritating fumes.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1048
It decomposes violently at high temperatures and pressures.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1048

3.2.13 Ionization Potential

8.56 eV

3.2.14 Polymerization

The substance will readily polymerize to dimer with fire or explosion hazard. The reaction is accelerated by peroxides or trichloroacetic acid.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of july 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm
Dimerization is highly exothermic, the rate increasing rapidly with temperature, and may cause rupture of a closed uncooled container ... The polymerization of the undiluted diene may become explosive within the range 0 to 40 °C and at pressures up to 340 bar ...
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 522

3.2.15 Odor Threshold

Odor Threshold Low: 1.8 [mmHg]

Odor threshold from AIHA

Low Threshold= 5.0 mg/cu m; High threshold= 5.0 mg/cu m.
Ruth JH; Am Ind Hyg Assoc J 47: A-142-51 (1986)

3.2.16 Refractive Index

Index of refraction = 1.4440 at 20 °C/D
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 3-138
Index of refraction: 1.44632 at 16 °C/D
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 488

3.2.17 Dissociation Constants

3.2.18 Kovats Retention Index

Standard non-polar
538.1 , 533 , 542 , 545 , 541 , 542 , 543 , 545 , 540 , 546 , 528 , 525 , 538 , 530 , 535 , 522 , 540
Semi-standard non-polar
510.5 , 534.7 , 549.5 , 552.5 , 527 , 521.7 , 523 , 521.8 , 521.6 , 518 , 521 , 527 , 530 , 520.6 , 516.61 , 519 , 522 , 528 , 530 , 523 , 539 , 97.2
Standard polar
745.7 , 735

3.2.19 Other Experimental Properties

MP: -85 °C. Density: 0.8235 at 0 °C/4 °C; 0.8131 at 10 °C/4 °C; 0.7966 at 25 °C/4 °C; 0.7914 at 30 °C/4 °C
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 488
Cyclopentadiene polymerizes to dicyclopentadiene on standing; accelerated by peroxides or trichloroacetic acid.
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 488
Dimer has camphor-like odor. /dicyclopentadiene/
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 488
Cyclopentadiene undergoes self-condensation in a Diels-Alder reaction. /Cyclopentadiene/
CHEMICAL PRODUCTS SYNOPSIS: Dicyclopentadiene, 1981

3.3 SpringerMaterials Properties

3.4 Chemical Classes

Other Classes -> Aliphatics, Unsaturated

4 Spectral Information

4.1 1D NMR Spectra

1D NMR Spectra

4.1.1 13C NMR Spectra

1 of 2
Source of Sample
U. Edlund Uni Umea Sweden (1979)
Copyright
Copyright © 1980, 1981-2024 John Wiley & Sons, Inc. All Rights Reserved.
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Copyright
Copyright © 2002-2024 Wiley-VCH Verlag GmbH & Co. KGaA. All Rights Reserved.
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4.2 Mass Spectrometry

4.2.1 GC-MS

1 of 4
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NIST Number
196
Library
Main library
Total Peaks
38
m/z Top Peak
66
m/z 2nd Highest
65
m/z 3rd Highest
39
Thumbnail
Thumbnail
2 of 4
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NIST Number
60843
Library
Replicate library
Total Peaks
34
m/z Top Peak
66
m/z 2nd Highest
65
m/z 3rd Highest
39
Thumbnail
Thumbnail

4.2.2 Other MS

Other MS
MASS: 60843 (NIST/EPA/MSDC Mass Spectral Database, 1990 version)

4.3 UV Spectra

MAX ABSORPTION (ALCOHOL): 238 NM (LOG E= 3.62)
Weast, R.C. (ed.). Handbook of Chemistry and Physics. 60th ed. Boca Raton, Florida: CRC Press Inc., 1979., p. C-267
UV: 6-42 (Organic Electronic Spectral Data, Phillips et al, John Wiley & Sons, New York)
Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V3: 2328

4.4 IR Spectra

IR Spectra
IR: 2691 (Coblentz Society Spectral Collection)

6 Chemical Vendors

7 Pharmacology and Biochemistry

7.1 Absorption, Distribution and Excretion

Routes of Entry: Inhalation, ingestion, skin and/or eye contact.
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 5th Edition Volume 1: A-H,Volume 2: I-Z. William Andrew, Norwich, NY 2008, p. 786
The substance can be absorbed into the body by inhalation.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm

8 Use and Manufacturing

8.1 Uses

Sources/Uses
Used in resin manufacturing and other organic syntheses; [ACGIH]
ACGIH - Documentation of the TLVs and BEIs, 7th Ed. Cincinnati: ACGIH Worldwide, 2020.
Manufacturing resins; in organic synthesis as the diene in Diels-Alder reaction producing sesquiterpenes, synthetic alkaloids, camphors.
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 488
Starting material for synthetic prostaglandins; chlorinated insecticides; formation of sandwich compounds by chelation, for example, cyclopentadienyl iron dicarbonyl dimer.
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 362

8.1.1 Use Classification

Hazard Classes and Categories -> Flammable - 3rd degree

8.1.2 Industry Uses

  • Monomers
  • Intermediate
  • Intermediates
  • Plasticizers

8.1.3 Consumer Uses

  • Intermediates
  • Plasticizers
  • Monomers

8.2 Methods of Manufacturing

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.
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 488
... 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.
Honicke D et al; Cyclopentadiene and Cyclopentane. Ullmann's Encyclopedia of Industrial Chemistry 7th ed. (1999-2014). NY, NY: John Wiley & Sons. Online Posting Date: June 15, 2000

8.3 Formulations / Preparations

High purity commercial form is supplied as a dimer, dicyclopentadiene
CHEMICAL PRODUCTS SYNOPSIS: Dicyclopentadiene, 1981

8.4 Consumption Patterns

Hydrocarbon resin systems, 50%; Unsaturated polyester resins, 27%; EPDM elastomers, 13%; Miscellaneous, including chemical synthesis, flame retardants, pesticides and agricultural chemicals, 10% (1984)
CHEMICAL PROFILE: Dicyclopentadiene, 1984

8.5 U.S. Production

Aggregated Product Volume

2019: 1,000,000 - <10,000,000 lb

2018: 1,000,000 - <10,000,000 lb

2017: 1,000,000 - <10,000,000 lb

2016: 1,000,000 - <10,000,000 lb

(1984) 4.39X10+10 g
USITC. SYN ORG CHEM-U.S.A PROD/SALES, 1984 p.25
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).
EPA/Office of Pollution Prevention and Toxics; High Production Volume (HPV) Challenge Program. 1,3-Cyclopentadiene (542-92-7). Available from, as of June 20, 2014: https://www.epa.gov/hpv/pubs/general/opptsrch.htm
Production volumes for non-confidential chemicals reported under the Inventory Update Rule.
Year
1986
Production Range (pounds)
>1 million - 10 million
Year
1990
Production Range (pounds)
>50 million - 100 million
Year
1994
Production Range (pounds)
>10 million - 50 million
Year
1998
Production Range (pounds)
>10 million - 50 million
Year
2002
Production Range (pounds)
>10 million - 50 million
US EPA; Non-confidential Production Volume Information Submitted by Companies for Chemicals Under the 1986-2002 Inventory Update Rule (IUR). 1,3-Cyclopentadiene (542-92-7). Available from, as of June12, 2014: https://epa.gov/cdr/tools/data/2002-vol.html
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.
US EPA; Non-Confidential 2006 Inventory Update Reporting. National Chemical Information. 1,3-Cyclopentadiene (542-92-7). Available from, as of June 20, 2014: https://cfpub.epa.gov/iursearch/index.cfm
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.
USEPA/Pollution Prevention and Toxics; 2014 Chemical Data Reporting Database. 1,3-Cyclopentadiene (542-92-7). Available from, as of June 20, 2014: https://java.epa.gov/oppt_chemical_search/

8.6 General Manufacturing Information

Industry Processing Sectors
  • Petrochemical Manufacturing
  • Plastics Material and Resin Manufacturing
  • Petroleum Refineries
  • All Other Basic Organic Chemical Manufacturing
EPA TSCA Commercial Activity Status
1,3-Cyclopentadiene: ACTIVE
EPA TSCA Regulatory Flag
SP - indicates a substance that is identified in a proposed Significant New Use Rule.
/The dimer/ ... is a more convenient form in which to handle cyclopentadiene, and is easily depolymerized by distilling at atmospheric pressure. /Cyclopentadiene dimer/
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 488

8.7 Sampling Procedures

NIOSH Method 2523. Analyte: 1,3-cyclopentadiene. Matrix: Air. Sampler: Solid sorbent tube (maleic anhydride on chromosorb 104, 100 mg/50 mg). Flow Rate: 0.01 to 0.05 L/min. Sample Size: 3 liters. Shipment: Routine. Sample Stability: At least 1 week @ 25 °C.
U.S. Department of Health and Human Services, Public Health Service. Centers for Disease Control, National Institute for Occupational Safety and Health. NIOSH Manual of Analytical Methods, 3rd ed. Volumes 1 and 2 with 1985 supplement, and revisions. Washington, DC: U.S. Government Printing Office, February 1984., p. 2523-1

9 Identification

9.1 Analytic Laboratory Methods

Method: NIOSH 2523; Procedure: gas chromatography with flame ionization detector; Analyte: 1,3-cyclopentadiene; Matrix: air; Detection Limit: 0.01 mg/sample.
CDC; NIOSH Manual of Analytical Methods, 4th ed. 1,3-Cyclopentadiene (542-92-7). Available from, as of July 22, 2014: https://www.cdc.gov/niosh/docs/2003-154/
A method is proposed for determining cyclopentadiene in air of production facilities. This method is based on the formation of green or blue dianione from the interaction of cyclopentadiene with 1,4-dinitrobenzene in medium of dimethylformamide in presence of alkali.
Baranova VG, Loginova NK; Gig Tr Prof Zabol 3: 54 (1977)
Sensitivity of a thin-layer chromatographic method for cyclopentadiene in the air of coumarone-indene resin processing shops is 0.5 ug. This method is based on the formation of mercury acetate derivative in anhydrous solution of mercury acetate.
Tsendrovskaya VA; Gig Sanit 38 (1): 62 (1973)

9.2 NIOSH Analytical Methods

10 Safety and Hazards

10.1 Hazards Identification

10.1.1 GHS Classification

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Pictogram(s)
Flammable
Acute Toxic
Irritant
Signal
Danger
GHS Hazard Statements

H225 (24.8%): Highly Flammable liquid and vapor [Danger Flammable liquids]

H226 (75.2%): Flammable liquid and vapor [Warning Flammable liquids]

H301+H311 (24.5%): Toxic if swallowed or in contact with skin [Danger Acute toxicity, oral; acute toxicity, dermal]

H301 (91.8%): Toxic if swallowed [Danger Acute toxicity, oral]

H311 (26.2%): Toxic in contact with skin [Danger Acute toxicity, dermal]

H312 (65.6%): Harmful in contact with skin [Warning Acute toxicity, dermal]

H315 (100%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (100%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H332 (87%): Harmful if inhaled [Warning Acute toxicity, inhalation]

H335 (100%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

Precautionary Statement Codes

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

(The corresponding statement to each P-code can be found at the GHS Classification page.)

ECHA C&L Notifications Summary

Aggregated GHS information provided per 355 reports by companies from 8 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.

10.1.2 Hazard Classes and Categories

Flam. Liq. 2 (24.8%)

Flam. Liq. 3 (75.2%)

Acute Tox. 3 (91.8%)

Acute Tox. 3 (26.2%)

Acute Tox. 4 (65.6%)

Skin Irrit. 2 (100%)

Eye Irrit. 2 (100%)

Acute Tox. 4 (87%)

STOT SE 3 (100%)

Flammable liquids - Category 2

Acute toxicity (Oral) - Category 3

Acute toxicity (Dermal) - Category 3

Acute toxicity (Inhalation: Vapours) - Category 4

Serious eye damage/eye irritation - Category 2A-2B

Specific target organ toxicity - Single exposure - Category 3 (Respiratory tract irritation)

Specific target organ toxicity - Repeated exposure - Category 2 (liver, kidney)

10.1.3 Health Hazards

Excerpt from NIOSH Pocket Guide for Cyclopentadiene:

Exposure Routes: Inhalation, ingestion, skin and/or eye contact

Symptoms: Irritation eyes, nose

Target Organs: Eyes, respiratory system (NIOSH, 2024)

10.1.4 Fire Hazards

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

HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. 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 the ground and collect in low or confined areas (sewers, basements, tanks, etc.). Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids will float on water. Substance may be transported hot. For hybrid vehicles, ERG Guide 147 (lithium ion or sodium ion batteries) or ERG Guide 138 (sodium batteries) should also be consulted. If molten aluminum is involved, refer to ERG Guide 169. (ERG, 2024)

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

10.1.5 Hazards Summary

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.
ACGIH - Documentation of the TLVs and BEIs, 7th Ed. Cincinnati: ACGIH Worldwide, 2020., 1987
ACGIH - Documentation of the TLVs and BEIs, 7th Ed. Cincinnati: ACGIH Worldwide, 2020., 2019

10.1.6 Fire Potential

A dangerous fire hazard when exposed to heat or flame.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1048

10.1.7 Skin, Eye, and Respiratory Irritations

Exposure can irritate the eyes, skin, and respiratory tract. Skin contact causes a burning sensation and rash.
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 5th Edition Volume 1: A-H,Volume 2: I-Z. William Andrew, Norwich, NY 2008, p. 786
1,3-Cyclopentadiene is irritating to eyes and mucous membranes. It has caused contact dermatitis and sensitization.
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 4:189
ACUTE ... SYMPTOMS: Inhalation--cough and sore throat; Eyes--redness and pain.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm

10.2 Safety and Hazard Properties

10.2.1 Flammable Limits

Flammability
Class IC Flammable Liquid: Fl.P. at or above 73 °F and below 100 °F.

10.2.2 Physical Dangers

The vapour is heavier than air.

10.2.3 Explosive Limits and Potential

Moderate explosion hazard in the form of gas when exposed to heat or by chemical reaction.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1048
Studies on the fire & explosion hazard properties of petroleum cyclopentadiene. These products can be incl into group a of class 2 dangerously explosive mixtures. Explosion proof equipment is required in mfr.
MARDANOV ET AL; AKAD NAUK AZ SSR 11: 59 (1980)
Dimerization is highly exothermic, the rate increasing rapidly with temperature, and may cause rupture of a closed uncooled container ... The polymerization of the undiluted diene may become explosive within the range 0 to 40 °C and at pressures up to 340 bar ...
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 522
Above 25 °C explosive vapor/air mixtures may be formed.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm
The substance can readily form explosive peroxides on contact with air. The substance will readily polymerize to dimer with fire or explosion hazard. The reaction is accelerated by peroxides or trichloroacetic acid.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm

10.2.4 OSHA Standards

Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 75 ppm (200 mg/cu m).
29 CFR 1910.1000 (USDOL); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of June 19, 2014: https://www.ecfr.gov

10.2.5 NIOSH Recommendations

Recommended Exposure Limit: 10 Hr Time-Weighted avg: 75 ppm (200 mg/cu m).
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg

10.3 First Aid Measures

Inhalation First Aid
Fresh air, rest. Refer for medical attention.
Skin First Aid
Remove contaminated clothes. Rinse and then wash skin with water and soap.
Eye First Aid
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.
Ingestion First Aid
Rinse mouth. Seek medical attention if you feel unwell.

10.3.1 First Aid

Excerpt from NIOSH Pocket Guide for Cyclopentadiene:

Eye: IRRIGATE IMMEDIATELY - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: SOAP WASH PROMPTLY - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water. Get medical attention promptly.

Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.

Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2024)

(See general first aid procedures)

Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: Soap wash promptly - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water. Get medical attention promptly.

Breathing: Respiratory support

Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.

10.4 Fire Fighting

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)

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

10.4.1 Fire Fighting Procedures

Powder, aqueous film-forming foams (AFFF), foam, carbon dioxide ... Keep drums, etc, cool by spraying with water.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of October 03, 2006: https://www.inchem.org/documents/icsc/icsc/eics0857.htm
Dry chemical, carbon dioxide, foam
Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981., p. 2

10.4.2 Firefighting Hazards

The vapor is heavier than air ... A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20 °C.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm

10.5 Accidental Release Measures

10.5.1 Isolation and Evacuation

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)

10.5.2 Spillage Disposal

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.

10.5.3 Cleanup Methods

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).
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm
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.
Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981., p. 3

10.5.4 Disposal Methods

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
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 5th Edition Volume 1: A-H,Volume 2: I-Z. William Andrew, Norwich, NY 2008, p. 786

10.5.5 Preventive Measures

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.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
For more Preventive Measures (Complete) data for 1,3-CYCLOPENTADIENE (7 total), please visit the HSDB record page.

10.6 Handling and Storage

10.6.1 Nonfire Spill Response

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)

10.6.2 Safe Storage

Fireproof. Store only if stabilized. Cooled. Separated from incompatible materials. See Chemical Dangers.

10.6.3 Storage Conditions

A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20 °C.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 214: https://www.inchem.org/documents/icsc/icsc/eics0857.htm
Fireproof. Separated from strong oxidants, strong acids, potassium hydroxide. Cooled. Store only if stabilized.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm
Monomer may largely be prevented from dimerizing by storage at -80 °C or below.
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 522

10.7 Exposure Control and Personal Protection

10.7.2 Permissible Exposure Limit (PEL)

75.0 [ppm]
PEL-TWA (8-Hour Time Weighted Average)
75 ppm (200 mg/m³)
TWA 75 ppm (200 mg/m3)

10.7.3 Immediately Dangerous to Life or Health (IDLH)

750 ppm (NIOSH, 2024)

750.0 [ppm]

Excerpts from Documentation for IDLHs: Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Deichmann and Gerarde [1969] that 4 of 6 rats died from a 4­hour exposure to 2,000 ppm [Smyth et al. 1954]. . . . Human data: None relevant for use in determining the revised IDLH.

750 ppm
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg

750 ppm

See: 542927

10.7.4 Threshold Limit Values (TLV)

8 hr Time Weighted Avg (TWA): 75 ppm.
American Conference of Governmental Industrial Hygienists. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. ACGIH, Cincinnati, OH 2014, p. 23
Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded.
American Conference of Governmental Industrial Hygienists. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. ACGIH, Cincinnati, OH 2014, p. 5
0,5 ppm as TWA
TLV-TWA (Time Weighted Average)
0.5 ppm [2018]
TLV-STEL (Short Term Exposure Limit)
1 ppm [2018]

10.7.5 Inhalation Risk

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

10.7.6 Effects of Short Term Exposure

The substance is irritating to the eyes and respiratory tract. The substance is mildly irritating to the skin.

10.7.7 Personal Protective Equipment (PPE)

Excerpt from NIOSH Pocket Guide for Cyclopentadiene:

Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET (FLAMMABLE) - Work clothing that becomes wet should be immediately removed due to its flammability hazard (i.e., for liquids with a flash point <100 °F).

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift. (NIOSH, 2024)

Wear appropriate personal protective clothing to prevent skin contact.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
Wear appropriate eye protection to prevent eye contact.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
Respirator Recommendations: Up to 750 ppm:
Assigned Protection Factor (APF)
APF = 10
Respirator Recommendations
Any chemical cartridge respirator with organic vapor cartridge(s)
Assigned Protection Factor (APF)
APF = 50
Respirator Recommendations
Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister.
Assigned Protection Factor (APF)
APF = 25
Respirator Recommendations
Any powered, air-purifying respirator with organic vapor cartridge(s)
Assigned Protection Factor (APF)
APF = 10
Respirator Recommendations
Any supplied-air respirator.
Assigned Protection Factor (APF)
APF = 50
Respirator Recommendations
Any self-contained breathing apparatus with a full facepiece.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
Respirator Recommendations: Emergency or planned entry into unknown concentrations or IDLH conditions:
Assigned Protection Factor (APF)
APF = 10,000
Respirator Recommendations
Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode.
Assigned Protection Factor (APF)
APF = 10,000
Respirator Recommendations
Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
For more Personal Protective Equipment (PPE) (Complete) data for 1,3-CYCLOPENTADIENE (6 total), please visit the HSDB record page.

(See personal protection and sanitation codes)

Skin: Prevent skin contact - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: Prevent eye contact - Wear appropriate eye protection to prevent eye contact.

Wash skin: When contaminated

Remove: When wet (flammable)

Change: No recommendation

10.7.8 Respirator Recommendations

NIOSH/OSHA

Up to 750 ppm:

(APF = 10) Any chemical cartridge respirator with organic vapor cartridge(s)

(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister

(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s)

(APF = 10) Any supplied-air respirator

(APF = 50) Any self-contained breathing apparatus with a full facepiece

Emergency or planned entry into unknown concentrations or IDLH conditions:

(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:

(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister

Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

10.7.9 Preventions

Fire Prevention
NO open flames, NO sparks and NO smoking. Above 25 °C use a closed system, ventilation and explosion-proof electrical equipment. NO contact with incompatible materials:
Exposure Prevention
PREVENT GENERATION OF MISTS! STRICT HYGIENE!
Inhalation Prevention
Use ventilation, local exhaust or breathing protection.
Skin Prevention
Protective gloves.
Eye Prevention
Wear safety goggles.
Ingestion Prevention
Do not eat, drink, or smoke during work.

10.8 Stability and Reactivity

10.8.1 Air and Water Reactions

No rapid reaction with air. No rapid reaction with water.

10.8.2 Reactive Group

Hydrocarbons, Aliphatic Unsaturated

Conjugated Dienes

10.8.3 Reactivity Alerts

Highly Flammable

Explosive

10.8.4 Reactivity Profile

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.

10.8.5 Hazardous Reactivities and Incompatibilities

Reacts vigorously on contact with potassium hydroxide.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1048
Contact with the ethanolic base /eg potassium hydroxide/ causes vigorously exothermic resin formation.
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 522
Incompatible with nitric acid; oxides of nitrogen; oxygen; sulfuric acid.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1048
Dienes and acetylene derivatives are hypergolic on contact with concn nitric acid, ignition delay being 1 ms. Cyclopentadiene reacts explosively with fuming nitric acid, igniting under nitrogen ...
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 1165
For more Hazardous Reactivities and Incompatibilities (Complete) data for 1,3-CYCLOPENTADIENE (9 total), please visit the HSDB record page.

10.9 Transport Information

10.9.1 Shipment Methods and Regulations

Flammable liquids, n.o.s. require a label "FLAMMABLE LIQUIDS". Quantity limitations: Passenger aircraft/rail: 60L; Cargo aircraft only: 220L. It falls in Hazard Class 3 and Packin Group III.
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 5th Edition Volume 1: A-H,Volume 2: I-Z. William Andrew, Norwich, NY 2008, p. 786

10.9.2 DOT Label

Flammable Liquid

10.9.3 Packaging and Labelling

Airtight. Unbreakable packaging.

10.9.4 UN Classification

UN Hazard Class: 3; UN Pack Group: III

10.10 Regulatory Information

The Australian Inventory of Industrial Chemicals
Chemical: 1,3-Cyclopentadiene
REACH Registered Substance
New Zealand EPA Inventory of Chemical Status
Cyclopentadiene: Does not have an individual approval but may be used under an appropriate group standard

10.10.1 TSCA Requirements

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.
40 CFR 712.30 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of June 19, 2014: https://www.ecfr.gov
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.
40 CFR 716.120 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of June 19, 2014: https://www.ecfr.gov

10.11 Other Safety Information

10.11.1 Toxic Combustion Products

Toxic gases & vapors (such as carbon monoxide) may be released in fire involving cyclopentadiene. /Cyclopentadiene/
Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981., p. 2

11 Toxicity

11.1 Toxicological Information

11.1.1 Toxicity Summary

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.

11.1.2 RAIS Toxicity Values

Inhalation Subchronic Reference Concentration (RfCs) (mg/m^3)
3
Inhalation Subchronic Reference Concentration Reference
HEAST Current

11.1.3 NIOSH Toxicity Data

11.1.4 Exposure Routes

The substance can be absorbed into the body by inhalation.
inhalation, ingestion, skin and/or eye contact

11.1.5 Symptoms

Inhalation Exposure
Cough. Sore throat.
Skin Exposure
Redness.
Eye Exposure
Redness. Pain.
Ingestion Exposure
Nausea. Vomiting.
irritation eyes, nose

11.1.6 Target Organs

Eyes, respiratory system

11.1.7 Adverse Effects

Neurotoxin - Acute solvent syndrome

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.

11.1.8 Acute Effects

11.1.9 Toxicity Data

LC67 (rat) = 2,000 ppm/4H

11.1.10 Interactions

An added stabilizer or inhibitor can influence the toxicological properties of this substance.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm

11.1.11 Antidote and Emergency Treatment

FIRST AID: Inhalation--Fresh air, rest. Refer for medical attention. Skin--Remove contaminated clothes. Rinse and then wash skin with water and soap. Eyes--First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor. Ingestion--Rinse mouth. Refer for medical attention.
IPCS, CEC; International Chemical Safety Card on Cyclopentadiene. (March 1996). Available from, as of July 25, 2014: https://www.inchem.org/documents/icsc/icsc/eics0857.htm
/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Aromatic hydrocarbons and related compounds/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 209
/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Aromatic hydrocarbons and related compounds/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 209-10
/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Consider drug therapy for pulmonary edema ... . Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias if necessary ... Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... .Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Aromatic hydrocarbons and related compounds/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 210

11.1.12 Medical Surveillance

If symptoms develop or overexposure is suspected, the following may be useful: liver and kidney function tests. Evaluation by a a qualified allergist, including careful exposure history and special testing, may help diagnose skin allergy.
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 5th Edition Volume 1: A-H,Volume 2: I-Z. William Andrew, Norwich, NY 2008, p. 786

11.1.13 Human Toxicity Excerpts

/SIGNS AND SYMPTOMS/ Short Term Exposure: Exposure can irritate the eyes, skin, and respiratory tract. Skin contact causes a burning sensation and rash.
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 5th Edition Volume 1: A-H,Volume 2: I-Z. William Andrew, Norwich, NY 2008, p. 786
/SIGNS AND SYMPTOMS/ Human sensory response was distinctly unfavorable at both 250 and 500 ppm cyclopentadiene in terms of irritating, objectionable odor.
American Conference of Governmental Industrial Hygienists. Documentation of the TLVs and BEIs with Other World Wide Occupational Exposure Values. 7th Ed. CD-ROM Cincinnati, OH 45240-1634 2013., p. 1
/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.
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 5th Edition Volume 1: A-H,Volume 2: I-Z. William Andrew, Norwich, NY 2008, p. 786

11.1.14 Non-Human Toxicity Excerpts

/LABORATORY ANIMALS: Acute Exposure/ /1,3-Cyclopentadiene/ vapors produce CNS depression in the frog in 10 min, but recovery is complete in 70 min.
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 4:189
/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ 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 of rats (e.g., centrilobular, cloudy swelling of liver cells and cloudy vacuolization of renal tubular epithelium), repeated, daily exposures at 250 ppm for 135 times produced no manifest effects in rabbits, rats, guinea pigs, and dogs. Hematologic effects were noticeably absent.
American Conference of Governmental Industrial Hygienists. Documentation of the TLVs and BEIs with Other World Wide Occupational Exposure Values. 7th Ed. CD-ROM Cincinnati, OH 45240-1634 2013., p. 1
/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ ... Exposures of 39 dogs at 400 ppm for 6 hours, followed by 16 six-hour exposures at double this average concentration produced no ill effects as judged by body weight, sedimentation rates, red and white blood cell counts, liver function tests, serum transaminase activities (serum glutamic-pyruvic transaminase and serum glutamic-oxaloacetic transaminase), electrocardiograms, or gross and microscopic examinations of critical organs.
American Conference of Governmental Industrial Hygienists. Documentation of the TLVs and BEIs with Other World Wide Occupational Exposure Values. 7th Ed. CD-ROM Cincinnati, OH 45240-1634 2013., p. 1
/LABORATORY ANIMALS: Neurotoxicity/ ... Subcutaneous injection of 3 cc into rabbits was a /CNS depressing/ dose with fatal convulsions; however, injections of 0.5 to 1.0 cc did not induce /CNS depression in/ the animals. 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.
American Conference of Governmental Industrial Hygienists. Documentation of the TLVs and BEIs with Other World Wide Occupational Exposure Values. 7th Ed. CD-ROM Cincinnati, OH 45240-1634 2013., p. 1

11.1.15 Non-Human Toxicity Values

LC50 Rat inhalation 39 mg/L/1 hr
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 4:189
LC50 Mouse inhalation 15 mg/L/1 hr
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 4:189

11.2 Ecological Information

11.2.1 Environmental Fate / Exposure Summary

1,3-Cyclopentadiene's production and use as a chemical intermediate may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 435 mm Hg at 25 °C indicates 1,3-cyclopentadiene will exist solely as a vapor in the atmosphere. Vapor-phase 1,3-cyclopentadiene will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone; the half-lives for these reactions in air are estimated to be 2.5 hours and 52 min, respectively. Reaction of 1,3-cyclopentadiene with nitrate radicals in the night time atmosphere may also be a relevant removal mechanism. If released to soil, 1,3-cyclopentadiene is expected to have high mobility based upon an estimated Koc of 80. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 2.1X10-2 atm-cu m/mole. 1,3-Cyclopentadiene may volatilize from dry soil surfaces based upon its vapor pressure. If concentrated solution of 1,3-cyclopentadiene is released to soil or water (spilled), this compound is expected to polymerize spontaneously to dicyclopentadiene. If released into water, 1,3-cyclopentadiene is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 2.4 hours and 3.2 days, respectively. An estimated BCF of 14 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions (pH 5 to 9). Occupational exposure to 1,3-cyclopentadiene may occur through inhalation and dermal contact with this compound at workplaces where 1,3-cyclopentadiene is produced or used. Monitoring data indicate that the general population may be exposed to 1,3-cyclopentadiene via inhalation of ambient air, ingestion of contaminated drinking water, and dermal contact. (SRC)

11.2.2 Artificial Pollution Sources

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).
(1) Lewis RJ Sr; Hawley's Condensed Chemical Dictionary. 15th ed p.362 (2007)

11.2.3 Environmental Fate

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).
(1) Swann RL et al; Res Rev 85: 17-28 (1983)
(2) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of May 15, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(3) Daubert TE, Danner RP; Physical & Thermodynamic Properties of Pure Chemicals. New York, NY: Hemisphere Pub Corp (1989)
(4) Amoore JE, Hautala E; J Appl Toxicol 3: 272-90 (1983)
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).
(1) Swann RL et al; Res Rev 85: 17-28 (1983)
(2) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of May 15, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(3) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 7-4, 7-5, 15-1 to 15-29 (1990)
(4) Daubert TE, Danner RP; Physical & Thermodynamic Properties of Pure Chemicals. New York, NY: Hemisphere Pub Corp (1989)
(5) Amoore JE, Hautala E; J Appl Toxicol 3: 272-90 (1983)
(6) Mill T, Mabey W; Environmental Exposure from Chemicals Vol. II Neely WB, Blau GE (eds) Boca Raton, FL: CRC Press pp. 209-10 (1985)
(7) Franke C et al; Chemosphere 29: 1501-14 (1994)
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).
(1) Bidleman TF; Environ Sci Technol 22: 361-367 (1988)
(2) Daubert TE, Danner RP; Physical & Thermodynamic Properties of Pure Chemicals. New York, NY: Hemisphere Pub Corp (1989)
(3) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of May 15, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(4) Atkinson R et al; J Phys Chem 88: 1210-5 (1984)

11.2.4 Environmental Abiotic Degradation

The rate constant for the vapor-phase reaction of 1,3-cyclopentadiene with photochemically-produced hydroxyl radicals has been estimated as 1.4X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2.5 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of 1,3-cyclopentadiene with ozone has been estimated as 3.2X10-16 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 52 min at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(1). Reaction of 1,3-cyclopentadiene with nitrate radicals in the night time atmosphere may also be a relevant removal mechanism(2). Reaction of 1,3-cyclopentadiene with atomic oxygen in air is expected to be too slow to be environmentally relevant (estimated half-life 5.9 days)(3). Highly concentrated solutions of 1,3-cyclopentadiene, such as those which may occur in spill situations or landfills(SRC), are expected to polymerize spontaneously and exothermally to dicyclopentadiene(4). 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). Olefins, as a general class, are susceptible to reaction with photochemically-produced hydroxyl radicals and singlet oxygen in natural waters(5). 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(5).
(1) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of May 15, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(2) Atkinson R et al; J Phys Chem 88: 1210-5 (1984)
(3) USEPA; Health and Environmental Effects Document for Cyclopentadiene and Dicyclopentadiene ECAO-CIN-GO12 p. 7 (1987)
(4) Cheung TTP; Kirk-Othmer Encyclopedia of Chemical Technology. Cyclopentadiene and Dicyclopentadiene. Online Posting Date: Sept 14, 2001 (2005)
(5) Mill T, Mabey W; Environmental Exposure from Chemicals Vol. II Neely WB, Blau GE, eds., Boca Raton, FL: CRC Press pp. 209-10 (1985)

11.2.5 Environmental Bioconcentration

An estimated BCF of 14 was calculated in fish for 1,3-cyclopentadiene(SRC), using an estimated log Kow of 2.25(1) and a regression-derived equation(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).
(1) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of May 15, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(2) Franke C et al; Chemosphere 29: 1501-14 (1994)

11.2.6 Soil Adsorption / Mobility

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.
(1) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of May 15, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(2) Swann RL et al; Res Rev 85: 17-28 (1983)

11.2.7 Volatilization from Water / Soil

The Henry's Law constant for 1,3-cyclopentadiene is estimated as 2.1X10-2 atm-cu m/mole(SRC) derived from its vapor pressure, 435 mm Hg(1), and water solubility, 1800 mg/L(2). This Henry's Law constant indicates that 1,3-cyclopentadiene is expected to volatilize rapidly from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 2.4 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 3.2 days(SRC). 1,3-Cyclopentadiene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 1,3-Cyclopentadiene is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).
(1) Daubert TE, Danner RP; Physical & Thermodynamic Properties of Pure Chemicals NY: Hemisphere Pub Corp (1989)
(2) Amoore JE, Hautala E; J Appl Toxicol 3: 272-90 (1983)
(3) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990)

11.2.8 Environmental Water Concentrations

DRINKING WATER: 1,3-Cyclopentadiene was qualitatively identified in drinking water at unspecified locations in the US(1-2). 1,3-Cyclopentadiene was detected at a concentration of 0.36 ppb in polluted drinking water from Czechoslovakia(3).
(1) Kool HJ et al; Crit Rev Environ Control 12: 307-57 (1982)
(2) Shackelford WM, Keith LH; Frequency of Organic Compounds Identified in Water USEPA 600/4-76-062 p. 105 (1976)
(3) Novak J et al; J Chromatog 76: 45-50 (1973)

11.2.9 Effluent Concentrations

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) Perry DL et al; Identification of Organic Compounds in Industrial Effluent Discharges PB-294794 p. 41 (1979)
(2) Junk GA, Ford CS; Chemosphere 9: 187-230 (1980)
(3) Graedel TE et al; Atmospheric Chemical Compounds NY: Academic Press p. 160 (1986)
(4) Perry R; Int Symp Ident Meas Environ Pollut p. 130-7 (1972)
(5) McDonald JD et al; Environ Sci Technol 34: 2080-91 (2000)
(6) Plata D et al; Environ Sci Technol 43: 8367-73 (2009
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).
(1) Sawyer RF; Environ Health Perspect 101: 5-12 supplement 6 (1993)
(2) Gabele P; J Air Waste Manage Assoc 47: 945-52 (1997)
(3) Kaiser EW et al; Environ Sci Technol 27: 1440-7 (1993)
(4) Foster P et al; Pollut Atmos 175-91 (1991)

11.2.10 Other Environmental Concentrations

1,3-Cyclopentadiene was detected in the gas phase of tobacco smoke at levels ranging from 0.06-7 ug/cigarette, with the amount of cyclopentadiene increasing with increasing tar delivery(1).
(1) Higgins CE et al; J Assoc Off Anal Chem 66: 1074-83 (1983)

11.2.11 Probable Routes of Human Exposure

According to the 2006 TSCA Inventory Update Reporting data, the number of persons reasonably likely to be exposed in the industrial manufacturing, processing, and use of 1,3-cyclopentadiene is 1-99; the data may be greatly underestimated(1).
(1) US EPA; Inventory Update Reporting (IUR). Non-confidential 2006 IUR Records by Chemical, including Manufacturing, Processing and Use Information. Washington, DC: U.S. Environmental Protection Agency. Available from, as of May 15, 2014: https://cfpub.epa.gov/iursearch/index.cfm
NIOSH (NOES Survey 1981-1983) has statistically estimated that 51 workers (none of these were female) were potentially exposed to 1,3-cyclopentadiene in the US(1). Occupational exposure to 1,3-cyclopentadiene may occur through inhalation and dermal contact with this compound at workplaces where 1,3-cyclopentadiene is produced or used. Monitoring data indicate that the general population may be exposed to 1,3-cyclopentadiene via inhalation of ambient air, ingestion of contaminated drinking water, and dermal contact(SRC).
(1) NIOSH; NOES. National Occupational Exposure Survey conducted from 1981-1983. Estimated numbers of employees potentially exposed to specific agents by 2-digit standard industrial classification (SIC). Available from, as of May 15, 2014: https://www.cdc.gov/noes/

12 Associated Disorders and Diseases

Associated Occupational Diseases with Exposure to the Compound
Solvents, acute toxic effect [Category: Acute Poisoning]

13 Literature

13.1 Consolidated References

13.2 NLM Curated PubMed Citations

13.3 Springer Nature References

13.4 Thieme References

13.5 Wiley References

13.6 Nature Journal References

13.7 Chemical Co-Occurrences in Literature

13.8 Chemical-Gene Co-Occurrences in Literature

13.9 Chemical-Disease Co-Occurrences in Literature

14 Patents

14.1 Depositor-Supplied Patent Identifiers

14.2 WIPO PATENTSCOPE

14.3 Chemical Co-Occurrences in Patents

14.4 Chemical-Disease Co-Occurrences in Patents

14.5 Chemical-Gene Co-Occurrences in Patents

15 Biological Test Results

15.1 BioAssay Results

16 Taxonomy

The LOTUS Initiative for Open Natural Products Research: frozen dataset union wikidata (with metadata) | DOI:10.5281/zenodo.5794106

17 Classification

17.1 MeSH Tree

17.2 ChEBI Ontology

17.3 ChemIDplus

17.4 CAMEO Chemicals

17.5 UN GHS Classification

17.6 NORMAN Suspect List Exchange Classification

17.7 EPA DSSTox Classification

17.8 EPA TSCA and CDR Classification

17.9 LOTUS Tree

17.10 EPA Substance Registry Services Tree

17.11 MolGenie Organic Chemistry Ontology

18 Information Sources

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    This work has been sponsored by the U.S. Department of Energy (DOE), Office of Environmental Management, Oak Ridge Operations (ORO) Office through a joint collaboration between United Cleanup Oak Ridge LLC (UCOR), Oak Ridge National Laboratory (ORNL), and The University of Tennessee, Ecology and Evolutionary Biology, The Institute for Environmental Modeling (TIEM). All rights reserved.
    https://rais.ornl.gov/
  17. The National Institute for Occupational Safety and Health (NIOSH)
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    https://www.cdc.gov/Other/disclaimer.html
  18. Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
    LICENSE
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    https://haz-map.com/About
  19. ChEBI
  20. LOTUS - the natural products occurrence database
    LICENSE
    The code for LOTUS is released under the GNU General Public License v3.0.
    https://lotus.nprod.net/
  21. ChEMBL
    LICENSE
    Access to the web interface of ChEMBL is made under the EBI's Terms of Use (http://www.ebi.ac.uk/Information/termsofuse.html). The ChEMBL data is made available on a Creative Commons Attribution-Share Alike 3.0 Unported License (http://creativecommons.org/licenses/by-sa/3.0/).
    http://www.ebi.ac.uk/Information/termsofuse.html
  22. Crystallography Open Database (COD)
    LICENSE
    All data in the COD and the database itself are dedicated to the public domain and licensed under the CC0 License. Users of the data should acknowledge the original authors of the structural data.
    https://creativecommons.org/publicdomain/zero/1.0/
  23. NITE-CMC
    1,3-Cyclopentadiene - FY2006 (New/original classication)
    https://www.chem-info.nite.go.jp/chem/english/ghs/06-imcg-0761e.html
    Cyclopentadiene - FY2019 (Revised classification)
    https://www.chem-info.nite.go.jp/chem/english/ghs/19-mhlw-2025e.html
    Cyclopentadiene - FY2014 (Revised classification)
    https://www.chem-info.nite.go.jp/chem/english/ghs/14-mhlw-2043e.html
  24. IUPAC Digitized pKa Dataset
  25. Japan Chemical Substance Dictionary (Nikkaji)
  26. KNApSAcK Species-Metabolite Database
  27. Metabolomics Workbench
  28. Nature Chemical Biology
  29. Nature Chemistry
  30. NIOSH Manual of Analytical Methods
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    The information provided using CDC Web site is only intended to be general summary information to the public. It is not intended to take the place of either the written law or regulations.
    https://www.cdc.gov/Other/disclaimer.html
  31. NIST Mass Spectrometry Data Center
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    https://www.nist.gov/srd/public-law
  32. SpectraBase
  33. NMRShiftDB
  34. Springer Nature
  35. SpringerMaterials
  36. Thieme Chemistry
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    The Thieme Chemistry contribution within PubChem is provided under a CC-BY-NC-ND 4.0 license, unless otherwise stated.
    https://creativecommons.org/licenses/by-nc-nd/4.0/
  37. Wikidata
  38. Wikipedia
  39. Wiley
  40. Medical Subject Headings (MeSH)
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    https://www.nlm.nih.gov/copyright.html
  41. PubChem
  42. GHS Classification (UNECE)
  43. NORMAN Suspect List Exchange
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    https://creativecommons.org/licenses/by/4.0/
    NORMAN Suspect List Exchange Classification
    https://www.norman-network.com/nds/SLE/
  44. EPA Substance Registry Services
  45. MolGenie
    MolGenie Organic Chemistry Ontology
    https://github.com/MolGenie/ontology/
  46. PATENTSCOPE (WIPO)
CONTENTS