Isoprene

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Condensed phase thermochemistry data

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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:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Δcliquid-754.83 ± 0.38kcal/molCcbJessup, 1938Reanalyzed by Cox and Pilcher, 1970, Original value = -754.52 ± 0.38 kcal/mol; Corresponding Δfliquid = 11.3 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity Value Units Method Reference Comment
liquid54.560cal/mol*KN/AMesserly, Todd, et al., 1970DH
liquid54.78cal/mol*KN/AWarfield and Petree, 1965DH
liquid54.80cal/mol*KN/ABekkedahl and Wood, 1937DH

Constant pressure heat capacity of liquid

Cp,liquid (cal/mol*K) Temperature (K) Reference Comment
36.109298.15Messerly, Todd, et al., 1970T = 12 to 320 K.; DH
36.45298.15Warfield and Petree, 1965T = 20 to 300 K. A reexamination of 37BEK/WOO.; DH
36.47298.2Bekkedahl and Wood, 1937T = 20 to 300 K.; DH

Reaction thermochemistry data

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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
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
RCD - Robert C. Dunbar

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Individual Reactions

C5H7- + Hydrogen cation = Isoprene

By formula: C5H7- + H+ = C5H8

Quantity Value Units Method Reference Comment
Δr385.6 ± 5.1kcal/molG+TSBartmess and McIver Jr., 1979gas phase; Between H2O, MeOH. Acid: isoprene; B
Quantity Value Units Method Reference Comment
Δr379.0 ± 5.0kcal/molIMRBBartmess and McIver Jr., 1979gas phase; Between H2O, MeOH. Acid: isoprene; B

3-Methyl-4-cyclohexene-1,1,2,2-tetracarbonitrile = Tetracyanoethylene + Isoprene

By formula: C11H8N4 = C6N4 + C5H8

Quantity Value Units Method Reference Comment
Δr37.6 ± 0.8kcal/molCmRogers, 1971solid phase; Heat of formation derived by 77PED/RYL; ALS

Tetracyanoethylene + Isoprene = 3-Methyl-4-cyclohexene-1,1,2,2-tetracarbonitrile

By formula: C6N4 + C5H8 = C11H8N4

Quantity Value Units Method Reference Comment
Δr-37.6 ± 0.8kcal/molCmRogers, 1971liquid phase; solvent: Dichloromethane; ALS

Silver ion (1+) + Isoprene = (Silver ion (1+) • Isoprene)

By formula: Ag+ + C5H8 = (Ag+ • C5H8)

Quantity Value Units Method Reference Comment
Δr39.2 ± 4.5kcal/molRAKHo, Yang, et al., 1997RCD

Gas phase ion energetics data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

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
LL - Sharon G. Lias and Joel F. Liebman
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 C5H8+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)8.86 ± 0.02eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)197.5kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity190.6kcal/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
8.85 ± 0.02PEBieri, Burger, et al., 1977LLK
8.85EILossing and Traeger, 1975LLK
8.90 ± 0.10EIPuttemans and Delvaux, 1973LLK
8.89PEBeez, Bieri, et al., 1973LLK
8.845 ± 0.005PIWatanabe, Nakayama, et al., 1962RDSH
8.84 ± 0.01SPrice and Walsh, 1940RDSH
8.85PEWerstiuk, Clark, et al., 1990Vertical value; LL
8.85PEMasclet, Mouvier, et al., 1981Vertical value; LLK
8.87PEWorley, Webb, et al., 1979Vertical value; LLK
9.04PESustmann and Schubert, 1972Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
C3H3+14.55 ± 0.15C2H4+HEIPuttemans and Delvaux, 1973LLK
C3H4+12.39 ± 0.12C2H4EIPuttemans and Delvaux, 1973LLK
C3H5+14.04 ± 0.10C2H2+HEIPuttemans and Delvaux, 1973LLK
C3H6+12.76 ± 0.10C2H2EIPuttemans and Delvaux, 1973LLK
C4H5+11.44CH3EILossing and Holmes, 1984LBLHLM
C4H5+11.93 ± 0.10CH3EIPuttemans and Delvaux, 1973LLK
C5H5+13.9H2+HEIHarrison, Haynes, et al., 1965RDSH
C5H7+10.54HEILossing and Traeger, 1975LLK
C5H7+10.54HEIHolmes, 1974LLK
C5H7+10.93 ± 0.10HEIPuttemans and Delvaux, 1973LLK

De-protonation reactions

C5H7- + Hydrogen cation = Isoprene

By formula: C5H7- + H+ = C5H8

Quantity Value Units Method Reference Comment
Δr385.6 ± 5.1kcal/molG+TSBartmess and McIver Jr., 1979gas phase; Between H2O, MeOH. Acid: isoprene; B
Quantity Value Units Method Reference Comment
Δr379.0 ± 5.0kcal/molIMRBBartmess and McIver Jr., 1979gas phase; Between H2O, MeOH. Acid: isoprene; B

References

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

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Jessup, 1938
Jessup, R.S., Heat of combustion of isoprene, J. Res. NBS, 1938, 20, 589-597. [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]

Messerly, Todd, et al., 1970
Messerly, J.F.; Todd, S.S.; Guthrie, G.B., Chemical thermodynamic properties of the pentadienes, J. Chem. Eng. Data, 1970, 15, 227-232. [all data]

Warfield and Petree, 1965
Warfield, R.W.; Petree, M.C., Thermodynamic properties of natural rubber and isoprene, Die Makromol. Chemie, 1965, 84, 1-8. [all data]

Bekkedahl and Wood, 1937
Bekkedahl, N.; Wood, L.A., Entropy of isoprene from heat-capacity measurements, J. Res. NBS, 1937, 19, 551-558. [all data]

Bartmess and McIver Jr., 1979
Bartmess, J.E.; McIver Jr., The Gas Phase Acidity Scale in Gas Phase Ion Chemistry, Gas Phase Ion Chemistry, V. 2, M.T. Bowers, Ed., Academic Press, NY, 1979, Ch. 11, Elsevier, 1979. [all data]

Rogers, 1971
Rogers, F.E., Thermochemistry of the Diels-Alder reaction. I. Enthalpy of addition of isoprene to tetracyanoethylene, J. Phys. Chem., 1971, 75, 1734-1737. [all data]

Ho, Yang, et al., 1997
Ho, Y.-P.; Yang, Y.-C.; Klippenstein, S.J.; Dunbar, R.C., Binding Energies of Ag+ and Cd+ Complexes from Analysis of Radiative Association Kinetics, J. Phys. Chem. A, 1997, 101, 18, 3338, https://doi.org/10.1021/jp9637284 . [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]

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]

Puttemans and Delvaux, 1973
Puttemans, J.-P.; Delvaux, J.C., Ionisation et fragmentation d'isomeres C5H8 sous impact electronique. Spiropentane - methylenecyclobutane - isoprene, Ing. Chim. Brussell, 1973, 55(267-8), 7. [all data]

Beez, Bieri, et al., 1973
Beez, M.; Bieri, G.; Bock, H.; Heilbronner, E., The ionization potentials of butadiene, hexatriene, andtheir methyl derivatives: evidence for through space interaction between double bond π-orbitals and non-bonded pseudo-π orbitals of methyl groups?, Helv. Chim. Acta, 1973, 56, 1028. [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]

Price and Walsh, 1940
Price, W.C.; Walsh, A.D., The absorption spectra of conjugated dienes in the vacuum ultra-violet (1), Proc. Roy. Soc. (London), 1940, A174, 220. [all data]

Werstiuk, Clark, et al., 1990
Werstiuk, N.H.; Clark, K.B.; Leigh, W.J., Conformational analysis and structure elucidation of 2,3-dimethyl and 2,4-dimethyl-2,4-hexadienes by AM1 and He(I) ultraviolet photoelectron spectroscopy, Can. J. Chem., 1990, 68, 2078. [all data]

Masclet, Mouvier, et al., 1981
Masclet, P.; Mouvier, G.; Bocquet, J.F., Effets electroniques et effets steriques dus a la substitution alcoyle dans les dienes conjugues, J. Chim. Phys., 1981, 78, 99. [all data]

Worley, Webb, et al., 1979
Worley, S.D.; Webb, T.R.; Gibson, D.H.; Ong, T.-S., On the electronic structures of cyclobutadiene trimethylenemethane, J. Organomet. Chem., 1979, 168, 16. [all data]

Sustmann and Schubert, 1972
Sustmann, R.; Schubert, R., Photoelektronenspektroskopische bestimmung von substituenten-effekten. I. Subtituierte butadiene, Tetrahedron Lett., 1972, 27, 2739. [all data]

Lossing and Holmes, 1984
Lossing, F.P.; Holmes, J.L., Stabilization energy and ion size in carbocations in the gas phase, J. Am. Chem. Soc., 1984, 106, 6917. [all data]

Harrison, Haynes, et al., 1965
Harrison, A.G.; Haynes, P.; McLean, S.; Meyer, F., The mass spectra of methyl-substituted cyclopentadienes, J. Am. Chem. Soc., 1965, 87, 5099. [all data]

Holmes, 1974
Holmes, J.L., The mass spectra of isomeric hydrocarbons - II: The C5H8 isomers, spiropentane, cyclopentene, 1,3-pentadiene and isoprene; the mechanisms and energetics of their fragmentations, Org. Mass Spectrom., 1974, 8, 247. [all data]


Notes

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