Isobutane

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Gas 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
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity Value Units Method Reference Comment
Δfgas-134.2 ± 0.63kJ/molCcbPittam and Pilcher, 1972ALS
Δfgas-135.6 ± 0.54kJ/molCmProsen, Maron, et al., 1951see Prosen and Rossini, 1945, Rossini, 1935; ALS
Quantity Value Units Method Reference Comment
Δcgas-2869.0 ± 0.59kJ/molCcbPittam and Pilcher, 1972Corresponding Δfgas = -134.2 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δcgas-2867.6 ± 0.46kJ/molCmProsen, Maron, et al., 1951see Prosen and Rossini, 1945, Rossini, 1935; Corresponding Δfgas = -135.6 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS

Constant pressure heat capacity of gas

Cp,gas (J/mol*K) Temperature (K) Reference Comment
34.8150.Chen S.S., 1975Recommended values are in good agreement with those calculated by [ Pitzer K.S., 1946].; GT
47.28100.
60.29150.
71.84200.
89.91273.15
96.65298.15
97.15300.
124.43400.
149.24500.
170.37600.
188.28700.
203.64800.
216.94900.
228.451000.
238.491100.
247.151200.
254.721300.
261.291400.
267.021500.

Constant pressure heat capacity of gas

Cp,gas (J/mol*K) Temperature (K) Reference Comment
82.30 ± 0.06243.15Ernst G., 1970Other experimental values of heat capacity [ Sage B.H., 1937, Sage B.H., 1938] are less accurate, see [ Chen S.S., 1975]. Please also see Dailey B.P., 1943, Wacker P.F., 1947.; GT
89.97 ± 0.06273.15
95.21 ± 0.10293.15
100.67 ± 0.10313.15
106.37 ± 0.11333.15
109.66347.6
111.74 ± 0.11353.15
112.55359.4
119.62387.5
137.03452.5
152.93520.9
161.29561.7
169.70605.3
185.18692.7

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

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

C4H9- + Hydrogen cation = Isobutane

By formula: C4H9- + H+ = C4H10

Quantity Value Units Method Reference Comment
Δr1728. ± 8.4kJ/molBranDePuy, Gronert, et al., 1989gas phase; B
Δr1735. ± 20.kJ/molBranPeerboom, Rademaker, et al., 1992gas phase; B
Quantity Value Units Method Reference Comment
Δr1692. ± 8.8kJ/molH-TSDePuy, Gronert, et al., 1989gas phase; B
Δr1699. ± 21.kJ/molH-TSPeerboom, Rademaker, et al., 1992gas phase; B

C4H9- + Hydrogen cation = Isobutane

By formula: C4H9- + H+ = C4H10

Quantity Value Units Method Reference Comment
Δr1728. ± 8.4kJ/molBranDePuy, Gronert, et al., 1989gas phase; B
Δr1732. ± 8.4kJ/molBranDePuy, Bierbaum, et al., 1984gas phase; B
Quantity Value Units Method Reference Comment
Δr1697. ± 8.8kJ/molH-TSDePuy, Gronert, et al., 1989gas phase; B

1-Propene, 2-methyl- + Hydrogen = Isobutane

By formula: C4H8 + H2 = C4H10

Quantity Value Units Method Reference Comment
Δr-117.8 ± 0.42kJ/molChydKistiakowsky, Ruhoff, et al., 1935gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -118.78 ± 0.75 kJ/mol; At 355 °K; ALS

Butane = Isobutane

By formula: C4H10 = C4H10

Quantity Value Units Method Reference Comment
Δr-9.699kJ/molEqkPines, Kvetinskas, et al., 1945gas phase; Heat of isomerization; ALS

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)677.8kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity671.3kJ/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
Δr1728. ± 8.4kJ/molBranDePuy, Gronert, et al., 1989gas phase; B
Δr1735. ± 20.kJ/molBranPeerboom, Rademaker, et al., 1992gas phase; B
Quantity Value Units Method Reference Comment
Δr1692. ± 8.8kJ/molH-TSDePuy, Gronert, et al., 1989gas phase; B
Δr1699. ± 21.kJ/molH-TSPeerboom, Rademaker, et al., 1992gas phase; B

C4H9- + Hydrogen cation = Isobutane

By formula: C4H9- + H+ = C4H10

Quantity Value Units Method Reference Comment
Δr1728. ± 8.4kJ/molBranDePuy, Gronert, et al., 1989gas phase; B
Δr1732. ± 8.4kJ/molBranDePuy, Bierbaum, et al., 1984gas phase; B
Quantity Value Units Method Reference Comment
Δr1697. ± 8.8kJ/molH-TSDePuy, Gronert, et al., 1989gas phase; B

References

Go To: Top, Gas 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.

Pittam and Pilcher, 1972
Pittam, D.A.; Pilcher, G., Measurements of heats of combustion by flame calorimetry. Part 8.-Methane, ethane, propane, n-butane and 2-methylpropane, J. Chem. Soc. Faraday Trans. 1, 1972, 68, 2224-2229. [all data]

Prosen, Maron, et al., 1951
Prosen, E.J.; Maron, F.W.; Rossini, F.D., Heats of combustion, formation, and insomerization of ten C4 hydrocarbons, J. Res. NBS, 1951, 46, 106-112. [all data]

Prosen and Rossini, 1945
Prosen, E.J.; Rossini, F.D., Heats of formation and combustion of 1,3-butadiene and styrene, J. Res. NBS, 1945, 34, 59-63. [all data]

Rossini, 1935
Rossini, F.D., Heat of combustion of isobutane, J. Res. NBS, 1935, 15, 357-361. [all data]

Chen S.S., 1975
Chen S.S., Ideal gas thermodynamic properties and isomerization of n-butane and isobutane, J. Phys. Chem. Ref. Data, 1975, 4, 859-869. [all data]

Pitzer K.S., 1946
Pitzer K.S., The entropies and related properties of branched paraffin hydrocarbons, Chem. Rev., 1946, 39, 435-447. [all data]

Ernst G., 1970
Ernst G., Ideal and real gas state heat capacities Cp of C3H8, i-C4H10, C2F5Cl, CH2ClCF3, CF2ClCFCl2, and CHF2Cl, J. Chem. Thermodyn., 1970, 2, 787-791. [all data]

Sage B.H., 1937
Sage B.H., Phase equilibria in hydrocarbon systems. XX. Isobaric heat capacity of gaseous propane, n-butane, isobutane, and n-pentane, Ind. Eng. Chem., 1937, 29, 1309-1314. [all data]

Sage B.H., 1938
Sage B.H., Phase equilibrium in hydrocarbon systems. Thermodynamic properties of isobutane, Ind. Eng. Chem., 1938, 30, 673-681. [all data]

Dailey B.P., 1943
Dailey B.P., Heat capacities and hindered rotation in n-butane and isobutane, J. Am. Chem. Soc., 1943, 65, 44-46. [all data]

Wacker P.F., 1947
Wacker P.F., Heat capacities of gaseous oxygen, isobutane, and 1-butene from -30 to +90 C, J. Res. Nat. Bur. Stand., 1947, 38, 651-659. [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]

Kistiakowsky, Ruhoff, et al., 1935
Kistiakowsky, G.B.; Ruhoff, J.R.; Smith, H.A.; Vaughan, W.E., Heats of organic reactions. II. Hydrogenation of some simpler olefinic hydrocarbons, J. Am. Chem. Soc., 1935, 57, 876-882. [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]

Pines, Kvetinskas, et al., 1945
Pines, H.; Kvetinskas, B.; Kassel, L.S.; Ipatieff, V.N., Determination of equilibrium constants for butanes and pentanes, J. Am. Chem. Soc., 1945, 67, 631-637. [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]

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]


Notes

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