Cyclohexene

Formula: C₆H₁₀
Molecular weight: 82.1436
IUPAC Standard InChI: InChI=1S/C6H10/c1-2-4-6-5-3-1/h1-2H,3-6H2
IUPAC Standard InChIKey: HGCIXCUEYOPUTN-UHFFFAOYSA-N
CAS Registry Number: 110-83-8
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript.
Other names: Benzene tetrahydride; Benzene, tetrahydro-; Cyclohex-1-ene; Tetrahydrobenzene; 1,2,3,4-Tetrahydrobenzene; Cykloheksen; Hexanaphthylene; UN 2256; 1-Cyclohexene; NSC 24835
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Gas phase thermochemistry data

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Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-4.32 ± 0.98	kJ/mol	Ccr	Steele, Chirico, et al., 1996	ALS
Δ_fH°_gas	-4.7	kJ/mol	N/A	Good and Smith, 1969	Value computed using Δ_fH_liquid° value of -38.2±0.6 kj/mol from Good and Smith, 1969 and Δ_vapH° value of 33.5 kj/mol from Steele, Chirico, et al., 1996.; DRB
Δ_fH°_gas	-5.3	kJ/mol	N/A	Labbauf and Rossini, 1961	Value computed using Δ_fH_liquid° value of -38.8±0.6 kj/mol from Labbauf and Rossini, 1961 and Δ_vapH° value of 33.5 kj/mol from Steele, Chirico, et al., 1996.; DRB
Δ_fH°_gas	-7.1	kJ/mol	N/A	Epstein, Pitzer, et al., 1949	Value computed using Δ_fH_liquid° value of -40.6±0.8 kj/mol from Epstein, Pitzer, et al., 1949 and Δ_vapH° value of 33.5 kj/mol from Steele, Chirico, et al., 1996.; DRB
Quantity	Value	Units	Method	Reference	Comment
S°_gas	310.45	J/mol*K	N/A	Beckett C.W., 1948	GT

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
35.12	50.	Dorofeeva O.V., 1986	Recommended S(298.15 K) value agrees well with experimental one [ Beckett C.W., 1948], however calculated Cp(T) values are about 5 J/mol*K lower than those obtained from experimental measurements [ Montgomery J.B., 1942]. To fit calculated Cp(T) values to experiment, [ Beckett C.W., 1948] suggested existence of stable half-boat conformation. This suggestion was found to be incorrect later. [ Dorofeeva O.V., 1986] used more reliable data on molecular structure and their S(T) and Cp(T) values are in good agreement with results of detail force-field calculations [ Lenz T.G., 1990].; GT
43.06	100.
53.78	150.
67.35	200.
92.14	273.15
101.5 ± 3.0	298.15
102.16	300.
139.70	400.
173.27	500.
201.44	600.
224.91	700.
244.65	800.
261.38	900.
275.63	1000.
287.83	1100.
298.29	1200.
307.29	1300.
315.06	1400.
321.78	1500.

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
133.47	370.	Montgomery J.B., 1942	GT
141.42	390.
148.53	410.

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, IR Spectrum, References, Notes

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C₆H₁₀⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	8.95 ± 0.01	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	784.5	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	752.0	kJ/mol	N/A	Hunter and Lias, 1998	HL

Ionization energy determinations

IE (eV)	Method	Reference	Comment
8.94	PE	Kimura, Katsumata, et al., 1981	LLK
8.94 ± 0.02	PE	Bieri, Burger, et al., 1977	LLK
8.95	EI	Lossing and Traeger, 1975	LLK
8.94 ± 0.01	PE	Rang, Paldoia, et al., 1974	LLK
9.57 ± 0.05	EI	Praet, 1970	RDSH
8.99	EI	Lewis and Hamill, 1970	RDSH
8.92	PE	Demeo and Yencha, 1970	RDSH
8.95 ± 0.01	PI	Demeo and El-Sayed, 1970	RDSH
8.94	PE	Bischof and Heilbronner, 1970	RDSH
8.92 ± 0.02	EI	Winters and Collins, 1969	RDSH
8.95 ± 0.01	PI	Watanabe, 1957	RDSH
9.09	PE	Lambert, Xue, et al., 1986	Vertical value; LBLHLM
9.12	PE	Kobayashi, 1978	Vertical value; LLK
9.12	PE	Hentrich, Gunkel, et al., 1974	Vertical value; LLK
9.12	PE	Clary, Lewis, et al., 1974	Vertical value; LLK
9.11	PE	Asmus and Klessinger, 1974	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C₃H₃⁺	13.45 ± 0.18	?	EI	Winters and Collins, 1969	RDSH
C₃H₅⁺	13.68 ± 0.05	?	EI	Praet, 1970	RDSH
C₃H₅⁺	12.12 ± 0.12	?	EI	Winters and Collins, 1969	RDSH
C₄H₅⁺	13.31 ± 0.15	?	EI	Winters and Collins, 1969	RDSH
C₄H₆⁺	11.91 ± 0.05	C₂H₄	EI	Praet, 1970	RDSH
C₄H₆⁺	10.67 ± 0.06	?	EI	Winters and Collins, 1969	RDSH
C₅H₅⁺	13.57 ± 0.11	?	EI	Winters and Collins, 1969	RDSH
C₅H₇⁺	8.95	CH₃	EI	Lossing and Traeger, 1975, 2	LLK
C₅H₇⁺	10.27	CH₃	EI	Lossing and Traeger, 1975	LLK
C₅H₇⁺	11.22 ± 0.05	CH₃	EI	Praet, 1970	RDSH
C₅H₇⁺	10.18 ± 0.12	CH₃	EI	Winters and Collins, 1969	RDSH
C₆H₇⁺	12.13 ± 0.10	H₂+H	EI	Winters and Collins, 1969	RDSH
C₆H₉⁺	11.8 ± 0.05	H	EI	Praet, 1970	RDSH
C₆H₉⁺	10.62 ± 0.07	H	EI	Winters and Collins, 1969	RDSH

De-protonation reactions

C₆H₉^- + = Cyclohexene

By formula: C₆H₉^- + H⁺ = C₆H₁₀

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1617. ± 21.	kJ/mol	G+TS	Lee and Squires, 1986	gas phase; Between H2O, MeOH; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1586. ± 21.	kJ/mol	IMRB	Lee and Squires, 1986	gas phase; Between H2O, MeOH; B

IR Spectrum

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References, Notes

Data compiled by: Coblentz Society, Inc.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, IR Spectrum, Notes

Steele, Chirico, et al., 1996
Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Smith, N.K.; Tasker, I.R., Thermodynamic properties and ideal-gas enthalpies of formation for cyclohexene, phthalan (2,5-dihydrobenzo-3,4-furan), isoxazole, octylamine, dioctylamine, trioctylamine, phenyl isocyanate, and 1,4,5,6-tetrahydropyrimidine, J. Chem. Eng. Data, 1996, 41, 1269-1284. [all data]

Good and Smith, 1969
Good, W.D.; Smith, N.K., Enthalpies of combustion of toluene, benzene, cyclohexane, cyclohexene, methylcyclopentane, 1-methylcyclopentene, and n-hexane, J. Chem. Eng. Data, 1969, 14, 102-106. [all data]

Labbauf and Rossini, 1961
Labbauf, A.; Rossini, F.D., Heats of combustion, formation, and hydrogenation of 14 selected cyclomonoolefin hydrocarbons, J. Phys. Chem., 1961, 65, 476-480. [all data]

Epstein, Pitzer, et al., 1949
Epstein, M.B.; Pitzer, K.S.; Rossini, F.D., Heats, equilibrium constants, and free energies of formation of cyclopentene and cyclohexene, J. Res. NBS, 1949, 42, 379-382. [all data]

Beckett C.W., 1948
Beckett C.W., The thermodynamic properties and molecular structure of cyclopentene and cyclohexene, J. Am. Chem. Soc., 1948, 70, 4227-4230. [all data]

Dorofeeva O.V., 1986
Dorofeeva O.V., Thermodynamic properties of twenty-one monocyclic hydrocarbons, J. Phys. Chem. Ref. Data, 1986, 15, 437-464. [all data]

Montgomery J.B., 1942
Montgomery J.B., The heat capacity of organic vapors. IV. Benzene, fluorobenzene, toluene, cyclohexane, methylcyclohexane and cyclohexene, J. Am. Chem. Soc., 1942, 64, 2375-2377. [all data]

Lenz T.G., 1990
Lenz T.G., Force field calculation of equilibrium thermodynamic properties: Diels-Alder reaction of 1,3-butadiene and ethylene and Diels-Alder dimerization of 1,3-butadiene, J. Comput. Chem., 1990, 11, 351-360. [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Bieri, Burger, et al., 1977
Bieri, G.; Burger, F.; Heilbronner, E.; Maier, J.P., Valence ionization enrgies of hydrocarbons, Helv. Chim. Acta, 1977, 60, 2213. [all data]

Lossing and Traeger, 1975
Lossing, F.P.; Traeger, J.C., Stabilization in cyclopentadienyl, cyclopentenyl, and cyclopentyl cations, J. Am. Chem. Soc., 1975, 97, 1579. [all data]

Rang, Paldoia, et al., 1974
Rang, S.; Paldoia, P.; Talvari, A., Ionization potentials of unsaturated hydrocarbons. 2. Mono-substituted cyclopentenes and cyclohexenes, Eesti. NSV Tead. Akad. Toim., 1974, 354. [all data]

Praet, 1970
Praet, M.-Th., Ionisation et dissociation du 1-methyl-cyclopentene, du methylenecyclopentane et de quelques isomeres par impact d'electrons et de photons, Org. Mass Spectrom., 1970, 4, 65. [all data]

Lewis and Hamill, 1970
Lewis, D.; Hamill, W.H., Excited states of neutral molecular fragments from appearance potentials by electron impact in a mass spectrometer, J. Chem. Phys., 1970, 52, 6348. [all data]

Demeo and Yencha, 1970
Demeo, D.A.; Yencha, A.J., Photoelectron spectra of bicyclic and exocyclic olefins, J. Chem. Phys., 1970, 53, 4536. [all data]

Demeo and El-Sayed, 1970
Demeo, D.A.; El-Sayed, M.A., Ionization potential and structure of olefins, J. Chem. Phys., 1970, 52, 2622. [all data]

Bischof and Heilbronner, 1970
Bischof, P.; Heilbronner, E., Photoelektron-Spektren von Cycloalkenen und Cycloalkadienen, Helv. Chim. Acta, 1970, 53, 1677. [all data]

Winters and Collins, 1969
Winters, R.E.; Collins, J.H., Mass spectrometric studies of structural isomers. II.Mono- and bicyclic C₆H₁₀ molecules, Org. Mass Spectrom., 1969, 2, 299. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Lambert, Xue, et al., 1986
Lambert, J.B.; Xue, L.; Bosch, R.J.; Taba, K.M.; Marko, D.E.; Urano, S.; LeBreton, P.R., Through space interactions of double bonds by photoelectron spectroscopy, J. Am. Chem. Soc., 1986, 108, 7575. [all data]

Kobayashi, 1978
Kobayashi, T., A new rule for photoelectron angular distributions of molecules, Phys. Lett. A, 1978, 69, 31. [all data]

Hentrich, Gunkel, et al., 1974
Hentrich, G.; Gunkel, E.; Klessinger, M., Photoelektronenspektren organischer verbindungen. 4. Photoelektronenspektren ungesattigter carbonylverbindungen, J. Mol. Struct., 1974, 21, 231. [all data]

Clary, Lewis, et al., 1974
Clary, D.C.; Lewis, A.A.; Morland, D.; Murrell, J.N.; Heilbronner, E., Ionization potentials of cycloalkenes, J. Chem. Soc. Faraday Trans. 2, 1974, 70, 1889. [all data]

Asmus and Klessinger, 1974
Asmus, P.; Klessinger, M., Photoelectron spectra of organic compounds. VI. Exocyclic methylene compounds, Tetrahedron, 1974, 30, 2477. [all data]

Lossing and Traeger, 1975, 2
Lossing, F.P.; Traeger, J.C., Free radicals by mass spectrometry XLVI. Heats of formation of C₅H₇ and C₅H₉ radicals and cations., J. Am. Chem. Soc., 1975, 19, 9. [all data]

Lee and Squires, 1986
Lee, R.E.; Squires, R.R., Anionic homoaromaticity: A gas phase experimental study, J. Am. Chem. Soc., 1986, 105, 5078. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, IR Spectrum, References

Symbols used in this document:

AE	Appearance energy
C_p,gas	Constant pressure heat capacity of gas
IE (evaluated)	Recommended ionization energy
S°_gas	Entropy of gas at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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