1,3-Cyclopentadiene
- Formula: C5H6
- Molecular weight: 66.1011
- IUPAC Standard InChI: InChI=1S/C5H6/c1-2-4-5-3-1/h1-4H,5H2
- IUPAC Standard InChIKey: ZSWFCLXCOIISFI-UHFFFAOYSA-N
- CAS Registry Number: 542-92-7
- 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: Cyclopentadiene; Pentole; Pyropentylene; R-Pentine
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Reaction thermochemistry data
Go To: Top, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
MS - José A. Martinho Simões
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
+
=
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 353.9 ± 2.2 | kcal/mol | G+TS | Bartmess, Scott, et al., 1979 | gas phase; value altered from reference due to change in acidity scale; B |
| ΔrH° | 354.9 ± 2.9 | kcal/mol | G+TS | Cumming and Kebarle, 1978 | gas phase; B |
| ΔrH° | 357.2 ± 2.0 | kcal/mol | D-EA | Engelking and Lineberger, 1977 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 347.7 ± 2.0 | kcal/mol | IMRE | Bartmess, Scott, et al., 1979 | gas phase; value altered from reference due to change in acidity scale; B |
| ΔrG° | 348.7 ± 2.0 | kcal/mol | IMRE | Cumming and Kebarle, 1978 | gas phase; B |
+
= (
•
)
By formula: C5H5- + C5H6 = (C5H5- • C5H6)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | <8.60 | kcal/mol | IMRB | Meot-ner, 1988 | gas phase; B,M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrS° | 20. | cal/mol*K | N/A | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, DG<, ΔrH<; M |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | <2.6 ± 1.0 | kcal/mol | IMRB | Meot-ner, 1988 | gas phase; B |
Free energy of reaction
| ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 3.6 | 250. | PHPMS | Meot-ner, 1988 | gas phase; Entropy change calculated or estimated, DG<, ΔrH<; M |
+
=
By formula: C4H2O3 + C5H6 = C9H8O3
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -24.8 ± 0.5 | kcal/mol | Cm | Breslauer and Kabakoff, 1974 | liquid phase; solvent: Dioxane; ALS |
| ΔrH° | -25.78 | kcal/mol | Cm | Rogers and Quan, 1973 | liquid phase; Gas phase Diels-Alder; ALS |
2 +
=
By formula: 2H2 + C5H6 = C5H10
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -50.38 ± 0.20 | kcal/mol | Chyd | Kistiakowsky, Ruhoff, et al., 1936 | gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -50.87 ± 0.20 kcal/mol; At 355 °K; ALS |
+
= (
•
)
By formula: Cl- + C5H6 = (Cl- • C5H6)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrG° | <2.50 | kcal/mol | TDEq | French, Ikuta, et al., 1982 | gas phase; B |
Free energy of reaction
| ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 2.5 | 300. | PHPMS | French, Ikuta, et al., 1982 | gas phase; DG<; M |
+
=
By formula: C5H6 + C6N4 = C11H6N4
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -26.8 | kcal/mol | Kin | Samuilov, Bukharov, et al., 1981 | liquid phase; solvent: Chorobenzene; ALS |
| ΔrH° | -25.56 ± 0.70 | kcal/mol | Cm | Rogers, 1972 | liquid phase; ALS |
=
+
By formula: C7H8 = C5H6 + C2H2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 28.00 ± 0.50 | kcal/mol | Kin | Walsh and Wells, 1975 | gas phase; Reanalyzed by Pedley, Naylor, et al., 1986, Original value = 28.36 ± 0.32 kcal/mol; ALS |
2 (l) +
(cr) =
(cr) +
(g)
By formula: 2C5H6 (l) + Mg (cr) = C10H10Mg (cr) + H2 (g)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -34.06 ± 0.69 | kcal/mol | RSC | Hull, Reid, et al., 1967 | Please also see Pedley and Rylance, 1977 and Cox and Pilcher, 1970, 2.; MS |
C8H6MoO3 (solution) + 3 (solution) = C18H15MoN3O3 (solution) +
(solution)
By formula: C8H6MoO3 (solution) + 3C4H4N2 (solution) = C18H15MoN3O3 (solution) + C5H6 (solution)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -16.7 ± 0.69 | kcal/mol | RSC | Nolan, Hoff, et al., 1985 | solvent: Pyridine; Reaction temperature: 323 K; MS |
=
By formula: C5H6 = C5H6
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -47.8 ± 0.5 | kcal/mol | Ciso | Roth, Klarner, et al., 1980 | liquid phase; solvent: Heptane; ALS |
= 2
By formula: C10H12 = 2C5H6
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 17.300 | kcal/mol | Cm | Baur and Frater, 1941 | gas phase; Heat of dissociation; ALS |
2 +
=
+
By formula: 2HI + C5H6 = C5H8 + I2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -21.4 | kcal/mol | Eqk | Furuyama, Golden, et al., 1970 | gas phase; ALS |
=
+
By formula: C7H10 = C5H6 + C2H4
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 23.2 ± 0.60 | kcal/mol | Eqk | Walsh and Wells, 1976 | gas phase; ALS |
=
+
By formula: C11H6N4 = C5H6 + C6N4
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 25.56 ± 0.70 | kcal/mol | Cm | Rogers, 1972 | solid phase; ALS |
+
=
By formula: C5H6 + C2H2 = C7H8
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -28.0 ± 0.5 | kcal/mol | Eqk | Walsh and Wells, 1975 | gas phase; ALS |
2 =
By formula: 2C5H6 = C10H12
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -46.62 | kcal/mol | Eqk | Lenz and Vaughan, 1989 | gas phase; ALS |
2 = C10H12
By formula: 2C5H6 = C10H12
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -46.77 | kcal/mol | Eqk | Lenz and Vaughan, 1989 | gas phase; ALS |
References
Go To: Top, Reaction thermochemistry data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr.,
The gas phase acidity scale from methanol to phenol,
J. Am. Chem. Soc., 1979, 101, 6047. [all data]
Cumming and Kebarle, 1978
Cumming, J.B.; Kebarle, P.,
Summary of gas phase measurements involving acids AH. Entropy changes in proton transfer reactions involving negative ions. Bond dissociation energies D(A-H) and electron affinities EA(A),
Can. J. Chem., 1978, 56, 1. [all data]
Engelking and Lineberger, 1977
Engelking, P.C.; Lineberger, W.C.,
Laser photoelectron spectrometry of C5H5-: A determination of the electron affinity and Jahn-Teller coupling in cyclopentadienyl,
J. Chem. Phys., 1977, 67, 1412. [all data]
Meot-ner, 1988
Meot-ner, M.,
The Ionic Hydrogen Bond and Solvation. 7. Interaction Energies of Carbanions with Solvent Molecules,
J. Am. Chem. Soc., 1988, 110, 12, 3858, https://doi.org/10.1021/ja00220a022
. [all data]
Breslauer and Kabakoff, 1974
Breslauer, K.J.; Kabakoff, D.S.,
Enthalpy of the Diels-Alder reaction of cyclopentadiene and maleic anhydride,
J. Org. Chem., 1974, 39, 721-722. [all data]
Rogers and Quan, 1973
Rogers, F.E.; Quan, S.W.,
Thermochemistry of the Diels-Alder reaction. III. Heat of addition of cyclopentadience to maleic anhydride,
J. Phys. Chem., 1973, 77, 828-831. [all data]
Kistiakowsky, Ruhoff, et al., 1936
Kistiakowsky, G.B.; Ruhoff, J.R.; Smith, H.A.; Vaughan, W.E.,
Heats of organic reactions. IV. Hydrogenation of some dienes and of benzene,
J. Am. Chem. Soc., 1936, 58, 146-153. [all data]
Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G.,
Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]
French, Ikuta, et al., 1982
French, M.A.; Ikuta, S.; Kebarle, P.,
Hydrogen bonding of O-H and C-H hydrogen donors to Cl-. Results from mass spectrometric measurement of the ion-molecule equilibria RH + Cl- = RHCl-,
Can. J. Chem., 1982, 60, 1907. [all data]
Samuilov, Bukharov, et al., 1981
Samuilov, Ya.D.; Bukharov, S.V.; Konovalov, A.I.,
Reactivity of tetraphenylcyclopentadiene and tetracyclone in the Diels-Alder reaction with cyanoethylenes,
Zh. Org. Khim., 1981, 17, 2389-2393. [all data]
Rogers, 1972
Rogers, F.E.,
Thermochemistry of the Diels-Alder reactions. II. Heat of addition of several dienes to tetracyanoethylene,
J. Phys. Chem., 1972, 76, 106-109. [all data]
Walsh and Wells, 1975
Walsh, R.; Wells, J.M.,
The enthalpy of formation of bicyclo[2,2,1]hepta-2,5-diene. Thermodynamic functions of bicyclo[2,2,1]heptane and bicyclo[2,2,1]hepta-2,5-diene,
J. Chem. Thermodyn., 1975, 7, 149-154. [all data]
Pedley, Naylor, et al., 1986
Pedley, J.B.; Naylor, R.D.; Kirby, S.P.,
Thermochemical Data of Organic Compounds, Chapman and Hall, New York, 1986, 1-792. [all data]
Hull, Reid, et al., 1967
Hull, H.S.; Reid, A.F.; Turnbull, A.G.,
Inorg. Chem., 1967, 6, 805. [all data]
Pedley and Rylance, 1977
Pedley, J.B.; Rylance, J.,
Computer Analysed Thermochemical Data: Organic and Organometallic Compounds, University of Sussex, Brigton, 1977. [all data]
Cox and Pilcher, 1970, 2
Cox, J.D.; Pilcher, G.,
Thermochemistry of Organic and Organometallic Compounds
in Academic Press, New York, 1970. [all data]
Nolan, Hoff, et al., 1985
Nolan, S.P.; Hoff, C.D.; Landrum, J.T.,
J. Organometal. Chem., 1985, 282, 357. [all data]
Roth, Klarner, et al., 1980
Roth, W.R.; Klarner, F.-G.; Lennartz, H.-W.,
Heats of hydrogenation. II. Heat of hydrogenation of bicyclo[2.1.0]pent-2-ene, an antiaromatic system,
Chem. Ber., 1980, 113, 1806-1818. [all data]
Baur and Frater, 1941
Baur, E.; Frater, S.,
Kinetik der bildung und des zerfalls von dicyclopentadien,
Helv. Chim. Acta, 1941, 24, 768-783. [all data]
Furuyama, Golden, et al., 1970
Furuyama, S.; Golden, D.M.; Benson, S.W.,
Thermochemistry of cyclopentene and cyclopentadiene from studies of gas-phase equilibria,
J. Chem. Thermodyn., 1970, 2, 161-169. [all data]
Walsh and Wells, 1976
Walsh, R.; Wells, J.M.,
The enthalpy of formation and thermodynamic functions of bicyclo[2,2,1]hept-2-ene,
J. Chem. Thermodyn., 1976, 8, 55-60. [all data]
Lenz and Vaughan, 1989
Lenz, T.G.; Vaughan, J.D.,
Employing force-field calculations to predict equilibrium constants and other thermodynamic properties for the dimerization of 1,3-cyclopentadiene,
J. Phys. Chem., 1989, 93, 1592-1596. [all data]
Notes
Go To: Top, Reaction thermochemistry data, References
- Symbols used in this document:
T Temperature ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔrS° Entropy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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