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Isobutane

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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

Quantity Value Units Method Reference Comment
IE (evaluated)10.68 ± 0.11eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)162.0kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity160.4kcal/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
10.57ESTLuo and Pacey, 1992LL
10.74 ± 0.05EIFlesch and Svec, 1973LLK
10.69PIDewar and Worley, 1969RDSH
10.79PITurner and Al-Joboury, 1964RDSH
10.78PIAl-Joboury and Turner, 1964RDSH
10.57PIWatanabe, Nakayama, et al., 1962RDSH
~10.5PISteiner, Giese, et al., 1961RDSH
11.13PEKimura, Katsumata, et al., 1981Vertical value; LLK
11.0 ± 0.1PEBieri, Burger, et al., 1977Vertical value; LLK
11.4PEMurrell and Schmidt, 1972Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CH3+29.4 ± 0.2?EIOlmsted, Street, et al., 1964RDSH
C2H5+13.80C2H5EIOmura, 1961RDSH
C3H5+14.55?EIOmura, 1961RDSH
C3H6+10.89 ± 0.02CH4PIMead, Donchi, et al., 1980LLK
C3H6+10.91CH4EIWolkoff and Holmes, 1978LLK
C3H6+10.93 ± 0.03CH4PISteiner, Giese, et al., 1961RDSH
C3H7+11.16 ± 0.02CH3PIMead, Donchi, et al., 1980LLK
C3H7+11.16 ± 0.05CH3EIWilliams and Hamill, 1968RDSH
C3H7+11.23 ± 0.03CH3PISteiner, Giese, et al., 1961RDSH
C4H9+10.68 ± 0.02HPIMead, Donchi, et al., 1980LLK
C4H9+10.68 ± 0.03HPIMcLoughlin and Traeger, 1979LLK
C4H9+11.6HEIOmura, 1961RDSH

De-protonation reactions

C4H9- + Hydrogen cation = Isobutane

By formula: C4H9- + H+ = C4H10

Quantity Value Units Method Reference Comment
Deltar412.9 ± 2.0kcal/molBranDePuy, Gronert, et al., 1989gas phase; B
Deltar414.7 ± 4.8kcal/molBranPeerboom, Rademaker, et al., 1992gas phase; B
Quantity Value Units Method Reference Comment
Deltar404.3 ± 2.1kcal/molH-TSDePuy, Gronert, et al., 1989gas phase; B
Deltar406.1 ± 4.9kcal/molH-TSPeerboom, Rademaker, et al., 1992gas phase; B

C4H9- + Hydrogen cation = Isobutane

By formula: C4H9- + H+ = C4H10

Quantity Value Units Method Reference Comment
Deltar413.1 ± 2.0kcal/molBranDePuy, Gronert, et al., 1989gas phase; B
Deltar414.0 ± 2.0kcal/molBranDePuy, Bierbaum, et al., 1984gas phase; B
Quantity Value Units Method Reference Comment
Deltar405.7 ± 2.1kcal/molH-TSDePuy, Gronert, et al., 1989gas phase; B

References

Go To: Top, 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.

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]

Luo and Pacey, 1992
Luo, Y.-R.; Pacey, P.D., Effects of alkyl substitution on ionization energies of alkanes and haloalkanes and on heats of formation of their molecular cations. Part 2. Alkanes and chloro-, bromo- and iodoalkanes, Int. J. Mass Spectrom. Ion Processes, 1992, 112, 63. [all data]

Flesch and Svec, 1973
Flesch, G.D.; Svec, H.J., Fragmentation reactions in the mass spectrometer for C2-C5 alkanes, J. Chem. Soc. Faraday Trans. 2, 1973, 69, 1187. [all data]

Dewar and Worley, 1969
Dewar, M.J.S.; Worley, S.D., Photoelectron spectra of molecules. I. Ionization potentials of some organic molecules and their interpretation, J. Chem. Phys., 1969, 50, 654. [all data]

Turner and Al-Joboury, 1964
Turner, D.W.; Al-Joboury, M.I., Molecular photoelectron spectroscopy, Bull. Soc. Chim. Belges, 1964, 73, 428. [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]

Steiner, Giese, et al., 1961
Steiner, B.; Giese, C.F.; Inghram, M.G., Photoionization of alkanes. Dissociation of excited molecular ions, J. Chem. Phys., 1961, 34, 189. [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]

Murrell and Schmidt, 1972
Murrell, J.N.; Schmidt, W., Photoelectron spectroscopic correlation of the molecular orbitals of methane, ethane, propane, isobutane and neopentane, J. Chem. Soc. Faraday Trans. 2, 1972, 68, 1709. [all data]

Olmsted, Street, et al., 1964
Olmsted, J., III; Street, K., Jr.; Newton, A.S., Excess-kinetic-energy ions in organic mass spectra, J. Chem. Phys., 1964, 40, 2114. [all data]

Omura, 1961
Omura, I., Mass spectra at low ionizing voltage and bond dissociation energies of molecular ions from hydrocarbons, Bull. Chem. Soc. Japan, 1961, 34, 1227. [all data]

Mead, Donchi, et al., 1980
Mead, P.T.; Donchi, K.F.; Traeger, J.C.; Christie, J.R.; Derrick, P.J., Secondary hydrogen isotope effect in the unimolecular decomposition of 2-methylpropane radical cations, J. Am. Chem. Soc., 1980, 102, 3364. [all data]

Wolkoff and Holmes, 1978
Wolkoff, P.; Holmes, J.L., Fragmentations of alkane molecular ions, J. Am. Chem. Soc., 1978, 100, 7346. [all data]

Williams and Hamill, 1968
Williams, J.M.; Hamill, W.H., Ionization potentials of molecules and free radicals and appearance potentials by electron impact in the mass spectrometer, J. Chem. Phys., 1968, 49, 4467. [all data]

McLoughlin and Traeger, 1979
McLoughlin, R.G.; Traeger, J.C., Heat of formation for tert-butyl cation in the gas phase, J. Am. Chem. Soc., 1979, 101, 5791. [all data]

DePuy, Gronert, et al., 1989
DePuy, C.H.; Gronert, S.; Barlow, S.E.; Bierbaum, V.M.; Damrauer, R., The Gas Phase Acidities of the Alkanes, J. Am. Chem. Soc., 1989, 111, 6, 1968, https://doi.org/10.1021/ja00188a003 . [all data]

Peerboom, Rademaker, et al., 1992
Peerboom, R.A.L.; Rademaker, G.J.; Dekoning, L.J.; Nibbering, N.M.M., Stabilization of Cycloalkyl Carbanions in the Gas Phase, Rapid Commun. Mass Spectrom., 1992, 6, 6, 394, https://doi.org/10.1002/rcm.1290060608 . [all data]

DePuy, Bierbaum, et al., 1984
DePuy, C.H.; Bierbaum, V.M.; Damrauer, R., Relative Gas-Phase Acidities of the Alkanes, J. Am. Chem. Soc., 1984, 106, 4051. [all data]


Notes

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