1,3,5,7-Cyclooctatetraene

Formula: C₈H₈
Molecular weight: 104.1491
IUPAC Standard InChI: InChI=1S/C8H8/c1-2-4-6-8-7-5-3-1/h1-8H/b2-1-,3-1-,4-2-,5-3-,6-4-,7-5-,8-6-,8-7-
IUPAC Standard InChIKey: KDUIUFJBNGTBMD-BONZMOEMSA-N
CAS Registry Number: 629-20-9
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: [8]Annulene; Cyclooctatetraene; UN 2358
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Gas phase thermochemistry data

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Data compiled as indicated in comments:
DRB - Donald R. Burgess, Jr.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	71.13 ± 0.31	kcal/mol	N/A	Prosen, Johnson, et al., 1950	Value computed using Δ_fH_liquid° value of 254.5±1.3 kj/mol from Prosen, Johnson, et al., 1950 and Δ_vapH° value of 43.1±0.31 kj/mol from missing citation.; DRB
Quantity	Value	Units	Method	Reference	Comment
S°_gas	78.10 ± 0.35	cal/mol*K	N/A	Scott D.W., 1949	GT

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
8.564	50.	Dorofeeva O.V., 1986	Selected values of Cp(T) are in close agreement with those calculated by [ Lippincott E.R., 1951], while the S(T) values are 1.5-2.0 J/mol*K larger than obtained by [ Lippincott E.R., 1951].; GT
12.11	100.
15.90	150.
20.03	200.
26.883	273.15
29.30 ± 0.84	298.15
29.484	300.
38.678	400.
46.465	500.
52.811	600.
57.995	700.
62.292	800.
65.894	900.
68.939	1000.
71.532	1100.
73.745	1200.
75.645	1300.
77.280	1400.
78.695	1500.

Reaction thermochemistry data

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Data compiled as indicated in comments:
B - John E. Bartmess
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

C₈H₇^- + = 1,3,5,7-Cyclooctatetraene

By formula: C₈H₇^- + H⁺ = C₈H₈

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	382.7 ± 2.8	kcal/mol	G+TS	Kato, Lee, et al., 1997	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	374.8 ± 2.5	kcal/mol	IMRE	Kato, Lee, et al., 1997	gas phase; B

4 + 1,3,5,7-Cyclooctatetraene =

By formula: 4H₂ + C₈H₈ = C₈H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-97.96 ± 0.05	kcal/mol	Chyd	Turner, Meador, et al., 1957	liquid phase; solvent: Acetic acid; ALS

1,3,5,7-Cyclooctatetraene =

By formula: C₈H₈ = C₈H₈

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-34.35 ± 0.34	kcal/mol	Ciso	Prosen, Johnson, et al., 1947	liquid phase; ALS

1,3,5,7-Cyclooctatetraene =

By formula: C₈H₈ = c₈H₈

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.5 ± 0.6	kcal/mol	Eqk	Squillacote and Bergman, 1986	gas phase; ALS

Gas phase ion energetics data

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

View reactions leading to C₈H₈⁺ (ion structure unspecified)

Electron affinity determinations

EA (eV)	Method	Reference	Comment
0.570 ± 0.030	N/A	Miller, Viggiano, et al., 2002	B
0.550 ± 0.020	IMRE	Kato, Lee, et al., 1997	B
0.650 ± 0.043	LPES	Wenthold, Hrovat, et al., 1996	EA(D4h COT) = 1.099 ± 0.01 eV. D4H is TS, 10-11 kcal/mol above GS D8h; B
0.58 ± 0.10	CIDC	Denault, Chen, et al., 1998	entropy of attachment: -14.7±13 eu; B
<0.823919	PD	Gygax, Peters, et al., 1979	B
0.577 ± 0.043	ECD	Wentworth and Ristau, 1969	B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
8.03	PE	Fu and Dunbar, 1978	LLK
8.0	PE	Batich, Bischof, et al., 1973	LLK
8.21	PE	Dewar, Harget, et al., 1969	Unpublished result of M.J.S. Dewar and S.D. Worley; RDSH
8.04	PE	Al-Joboury and Turner, 1964	RDSH
7.99 ± 0.02	PI	Watanabe, Nakayama, et al., 1962	RDSH
8.43	PE	Fu and Dunbar, 1978	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C₃H₃⁺	13.40 ± 0.10	?	EI	Franklin and Carroll, 1969	RDSH
C₄H₂⁺	17.11 ± 0.10	2C₂H₂+H₂	EI	Franklin and Carroll, 1969	RDSH
C₄H₃⁺	18.16 ± 0.25	2C₂H₂+H	EI	Franklin and Carroll, 1969	RDSH
C₄H₄⁺	15.10 ± 0.10	2C₂H₂	EI	Franklin and Carroll, 1969	RDSH
C₅H₃⁺	16.41 ± 0.15	C₂H₂+CH₃?	EI	Franklin and Carroll, 1969	RDSH
C₆H₅⁺	14.58 ± 0.10	C₂H₂+H	EI	Franklin and Carroll, 1969	RDSH
C₆H₆⁺	9.4 ± 0.05	C₂H₂	TRPI	Lifshitz and Malinovich, 1984	LBLHLM
C₆H₆⁺	9.70 ± 0.12	C₂H₂	EI	Franklin and Carroll, 1969	RDSH
C₈H₆⁺	11.70 ± 0.10	H₂	EI	Franklin and Carroll, 1969	RDSH
C₈H₇⁺	10.90 ± 0.10	H	EI	Franklin and Carroll, 1969	RDSH

De-protonation reactions

C₈H₇^- + = 1,3,5,7-Cyclooctatetraene

By formula: C₈H₇^- + H⁺ = C₈H₈

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	382.7 ± 2.8	kcal/mol	G+TS	Kato, Lee, et al., 1997	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	374.8 ± 2.5	kcal/mol	IMRE	Kato, Lee, et al., 1997	gas phase; B

Gas Chromatography

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

Kovats' RI, non-polar column, isothermal

View large format table.

Column type	Active phase	Temperature (C)	I	Reference	Comment
Capillary	Squalane	70.	850.	Schomburg, 1966

Van Den Dool and Kratz RI, non-polar column, temperature ramp

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Column type	Active phase	I	Reference	Comment
Packed	SE-30	880.	Buchman, Cao, et al., 1984	He, Chromosorb AW, 40. C @ 10. min, 10. K/min, 210. C @ 30. min; Column length: 3.05 m

Van Den Dool and Kratz RI, non-polar column, custom temperature program

View large format table.

Column type	Active phase	I	Reference	Comment
Packed	SE-30	880.	Peng, Ding, et al., 1988	Supelcoport; Chromosorb; Column length: 3.05 m; Program: 40C(5min) => 10C/min => 200C or 250C (60min)

Van Den Dool and Kratz RI, polar column, temperature ramp

View large format table.

Column type	Active phase	I	Reference	Comment
Capillary	Carbowax 20M	1244.	Verzera, Campisi, et al., 2005	60. m/0.25 mm/0.25 μm, He, 45. C @ 0.17 min, 2. K/min; T_end: 250. C
Capillary	CP-Wax 52CB	1244.	Verzera, Campisi, et al., 2001	60. m/0.25 mm/0.25 μm, He, 45. C @ 0.17 min, 2. K/min; T_end: 250. C
Capillary	DB-Wax	1264.	Shimoda, Peralta, et al., 1996	60. m/0.25 mm/0.25 μm, He, 3. K/min; T_start: 50. C; T_end: 230. C
Packed	Carbowax 20M	1226.	Buchman, Cao, et al., 1984	He, Supelcoport, 40. C @ 10. min, 10. K/min, 210. C @ 30. min; Column length: 3.05 m

Normal alkane RI, non-polar column, temperature ramp

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Column type	Active phase	I	Reference	Comment
Capillary	CP Sil 8 CB	894.	Wang and Guo-Y. -L., 2004	30. m/0.25 mm/0.25 μm, He, 50. C @ 3. min, 10. K/min, 200. C @ 2. min

Normal alkane RI, non-polar column, custom temperature program

View large format table.

Column type	Active phase	I	Reference	Comment
Capillary	Squalane	850.	Chen, 2008	Program: not specified
Capillary	OV-1, SE-30, Methyl silicone, SP-2100, OV-101, DB-1, etc.	880.	Waggott and Davies, 1984	Hydrogen; Column length: 50. m; Column diameter: 0.32 mm; Program: not specified
Packed	SE-30	889.	Robinson and Odell, 1971	N2, Chromosorb W; Column length: 6.1 m; Program: 50C910min) => 20C/min => 90(6min) => 10C/min => 150C(hold)
Packed	Squalane	846.	Robinson and Odell, 1971	N2, Embacel; Column length: 3.0 m; Program: 25C(5min) => 2C/min => 35 => 4C/min => 95C(hold)

Normal alkane RI, polar column, custom temperature program

View large format table.

Column type	Active phase	I	Reference	Comment
Capillary	Carbowax 20M	1244.	Editorial paper, 2005	Program: not specified
Capillary	DB-Wax	1199.	Peng, Yang, et al., 1991	Program: not specified
Capillary	Carbowax 400, Carbowax 20M, Carbowax 1540, Carbowax 4000, Superox 06, PEG 20M, etc.	1226.	Waggott and Davies, 1984	Hydrogen; Column length: 50. m; Column diameter: 0.32 mm; Program: not specified

References

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

Prosen, Johnson, et al., 1950
Prosen, E.J.; Johnson, W.H.; Rossini, F.D., Heat of combustion and formation of 1,3,5,7-cyclooctatetraene and its heat of isomerization of styrene, J. Am. Chem. Soc., 1950, 72, 626-629. [all data]

Scott D.W., 1949
Scott D.W., Cyclooctatetraene: low-temperature heat capacity, heat of fusion, heat of vaporization, vapor pressure, and entropy, J. Am. Chem. Soc., 1949, 71, 1634-1636. [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]

Lippincott E.R., 1951
Lippincott E.R., The thermodynamic functions of cyclooctatetraene, J. Am. Chem. Soc., 1951, 73, 3889-3891. [all data]

Kato, Lee, et al., 1997
Kato, S.; Lee, H.S.; Gareyev, R.; Wenthold, P.G.; Lineberger, W.C.; DePuy, C.H.; Bierbaum, V.M., Experimental and Computational Studies of the Structures and Energetics of Cyclooctatetraene and Its Derivatives, J. Am. Chem. Soc., 1997, 119, 33, 7863, https://doi.org/10.1021/ja971433d . [all data]

Turner, Meador, et al., 1957
Turner, R.B.; Meador, W.R.; Doering, W.E.; Knox, L.H.; Mayer, J.R.; Wiley, D.W., Heats of hydrogenation. III. Hydrogenation of cycllooctatetraene and of some seven-membered non-benzenoid aromatic compounds, J. Am. Chem. Soc., 1957, 79, 4127-4133. [all data]

Prosen, Johnson, et al., 1947
Prosen, E.J.; Johnson, W.H.; Rossini, F.D., Heat of combustion and formation of 1,3,5,7-cyclooctatetraene and its heat of isomerization to styrene, J. Am. Chem. Soc., 1947, 69, 2068-2069. [all data]

Squillacote and Bergman, 1986
Squillacote, M.E.; Bergman, A., Trapping of 1,3,5,7-cyclooctatetraene valence tautomers. Thermodynamic stability of bicyclo[4.2.0]octa-2,4,7-triene, J. Org. Chem., 1986, 51, 3910-3911. [all data]

Miller, Viggiano, et al., 2002
Miller, T.M.; Viggiano, A.A.; Miller, A.E.S., Electron attachment and detachment: Cyclooctatetraene, J. Phys. Chem. A, 2002, 106, 43, 10200-10204, https://doi.org/10.1021/jp0205214 . [all data]

Wenthold, Hrovat, et al., 1996
Wenthold, P.G.; Hrovat, D.A.; Borden, W.T.; Lineberger, W.C., Transition State Spectroscopy of Cyclooctatetraene, Science, 1996, 272, 5267, 1456, https://doi.org/10.1126/science.272.5267.1456 . [all data]

Denault, Chen, et al., 1998
Denault, J.W.; Chen, G.D.; Cooks, R.G., Electron affinity of 1,3,5,7-cyclooctatetraene determined by the kinetic method, J. Am. Soc. Mass Spectrom., 1998, 9, 11, 1141-1145, https://doi.org/10.1016/S1044-0305(98)00092-0 . [all data]

Gygax, Peters, et al., 1979
Gygax, R.; Peters, H.L.; Brauman, J.I., Photodetachment of electrons from anions of high symmetry. Electron photodetachment spectra of the cycloctatetraenyl and perinaphthenyl anions, J. Am. Chem. Soc., 1979, 101, 2567. [all data]

Wentworth and Ristau, 1969
Wentworth, W.E.; Ristau, W., Thermal Electron Attachment Involving a Change in Molecular Geometry, J. Phys. Chem., 1969, 73, 7, 2126, https://doi.org/10.1021/j100727a005 . [all data]

Fu and Dunbar, 1978
Fu, E.W.; Dunbar, R.C., Photodissociation spectroscopy and structural rearrangements in ions of cyclooctatetraene, styrene and related molecules, J. Am. Chem. Soc., 1978, 100, 2283. [all data]

Batich, Bischof, et al., 1973
Batich, C.; Bischof, P.; Heilbronner, E., The photoelectron spectra of cyclooctatetraene and its hydrogenated derivatives, J. Electron Spectrosc. Relat. Phenom., 1973, 1, 333. [all data]

Dewar, Harget, et al., 1969
Dewar, M.J.S.; Harget, A.; Haselbach, E., Cyclooctatetraene and ions derived from it, J. Am. Chem. Soc., 1969, 91, 7521. [all data]

Al-Joboury and Turner, 1964
Al-Joboury, M.I.; Turner, D.W., Molecular photoelectron spectroscopy. Part II. A summary of ionization potentials, J. Chem. Soc., 1964, 4434. [all data]

Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J., Ionization potentials of some molecules, J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]

Franklin and Carroll, 1969
Franklin, J.L.; Carroll, S.R., The effect of molecular structure on ionic decomposition. I. An electron impact study of seven C₈H₈ isomers, J. Am. Chem. Soc., 1969, 91, 5940. [all data]

Lifshitz and Malinovich, 1984
Lifshitz, C.; Malinovich, Y., Time resolved photoionization mass spectrometry in the millisecond range, Int. J. Mass Spectrom. Ion Processes, 1984, 60, 99. [all data]

Schomburg, 1966
Schomburg, G., Gaschromatographische Retentionsdaten und struktur chemischer verbindungen. III. Alkylverzweigte und ungesättigte cyclische Kohlenwasserstoffe, J. Chromatogr., 1966, 23, 18-41, https://doi.org/10.1016/S0021-9673(01)98653-4 . [all data]

Buchman, Cao, et al., 1984
Buchman, O.; Cao, G.-Y.; Peng, C.T., Structure assignment by retention index in gas-liquid radiochromatography of substituted cyclohexenes, J. Chromatogr., 1984, 312, 75-90, https://doi.org/10.1016/S0021-9673(01)92765-7 . [all data]

Peng, Ding, et al., 1988
Peng, C.T.; Ding, S.F.; Hua, R.L.; Yang, Z.C., Prediction of Retention Indexes I. Structure-Retention Index Relationship on Apolar Columns, J. Chromatogr., 1988, 436, 137-172, https://doi.org/10.1016/S0021-9673(00)94575-8 . [all data]

Verzera, Campisi, et al., 2005
Verzera, A.; Campisi, S.; Zappalá, M., SUPELCO. Using SPME-GC-MS to characterize volatile components of honey as indicators of botanical origin, 2005, retrieved from http://www.sigmaaldrich.com/Brands/Supelco_Home/TheReporter.html. [all data]

Verzera, Campisi, et al., 2001
Verzera, A.; Campisi, S.; Zappalá, M.; Bonaccorsi, I., SPME-GC-MS analysis of honey volatile components for the characterization of different floral origin, Am. Lab. Fairfield Conn., 2001, 33, 15, 18-21. [all data]

Shimoda, Peralta, et al., 1996
Shimoda, M.; Peralta, R.R.; Osajima, Y., Headspace gas analysis of fish sauce, J. Agric. Food Chem., 1996, 44, 11, 3601-3605, https://doi.org/10.1021/jf960345u . [all data]

Wang and Guo-Y. -L., 2004
Wang, H.-Y.; Guo-Y. -L., Rapid analysis of the volatile compounds in the rhizomes of Rhodiola sachalinensis and Rhodiola sacra by static headspace-gas chromatography-tandem mass spectrometry, Anal. Letters, 2004, 37, 10, 2151-2161, https://doi.org/10.1081/AL-200026690 . [all data]

Chen, 2008
Chen, H.-F., Quantitative prediction of gas chromatography retention indices with support vector machines, radial basis neutral networks and multiple linear regression, Anal. Chim. Acta, 2008, 609, 1, 24-36, https://doi.org/10.1016/j.aca.2008.01.003 . [all data]

Waggott and Davies, 1984
Waggott, A.; Davies, I.W., Identification of organic pollutants using linear temperature programmed retention indices (LTPRIs) - Part II, 1984, retrieved from http://dwi.defra.gov.uk/research/completed-research/reports/dwi0383.pdf. [all data]

Robinson and Odell, 1971
Robinson, P.G.; Odell, A.L., A system of standard retention indices and its uses. The characterisation of stationary phases and the prediction of retention indices, J. Chromatogr., 1971, 57, 1-10, https://doi.org/10.1016/0021-9673(71)80001-8 . [all data]

Editorial paper, 2005
Editorial paper, Solid Phase Microextraction (SPME) Application Guide, The Reporter Europe (Supelco), 2005, 16, 5, 12-12. [all data]

Peng, Yang, et al., 1991
Peng, C.T.; Yang, Z.C.; Ding, S.F., Prediction of rentention idexes. II. Structure-retention index relationship on polar columns, J. Chromatogr., 1991, 586, 1, 85-112, https://doi.org/10.1016/0021-9673(91)80028-F . [all data]

Notes

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Symbols used in this document:

AE	Appearance energy
C_p,gas	Constant pressure heat capacity of gas
EA	Electron affinity
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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