Isobutane

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Phase change data

Go To: Top, Gas phase ion energetics data, Ion clustering data, 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:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
DH - Eugene S. Domalski and Elizabeth D. Hearing
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity Value Units Method Reference Comment
Tboil262. ± 2.KAVGN/AAverage of 24 out of 25 values; Individual data points
Quantity Value Units Method Reference Comment
Tfus140. ± 100.KAVGN/AAverage of 7 values; Individual data points
Quantity Value Units Method Reference Comment
Ttriple113.55KN/AYounglove and Ely, 1987Uncertainty assigned by TRC = 0.05 K; TRC
Ttriple113.55KN/AGoodwin and Haynes, 1982Uncertainty assigned by TRC = 0.02 K; TRC
Ttriple113.74KN/AAston, Kennedy, et al., 1940Uncertainty assigned by TRC = 0.07 K; TRC
Ttriple113.2KN/AParks, Shomate, et al., 1937Uncertainty assigned by TRC = 0.2 K; TRC
Quantity Value Units Method Reference Comment
Ptriple1.9481×10-7barN/AYounglove and Ely, 1987Uncertainty assigned by TRC = 2.×10-10 bar; TRC
Ptriple1.9481×10-7barN/AGoodwin and Haynes, 1982Uncertainty assigned by TRC = 5.×10-10 bar; TRC
Quantity Value Units Method Reference Comment
Tc407.7 ± 0.8KAVGN/AAverage of 10 values; Individual data points
Quantity Value Units Method Reference Comment
Pc36.5 ± 0.5barAVGN/AAverage of 9 values; Individual data points
Quantity Value Units Method Reference Comment
Vc0.259l/molN/ADaubert, 1996 
Vc0.2591l/molN/AYounglove and Ely, 1987Uncertainty assigned by TRC = 0.001 l/mol; TRC
Quantity Value Units Method Reference Comment
ρc3.85 ± 0.05mol/lN/ADaubert, 1996 
ρc3.880mol/lN/ALevelt Sengers, Kamgar-Parsi, et al., 1983Uncertainty assigned by TRC = 0.009 mol/l; TRC
ρc3.91mol/lN/AWaxman and Gallagher, 1983Uncertainty assigned by TRC = 0.09 mol/l; TRC
ρc3.8601mol/lN/AGoodwin and Haynes, 1982Uncertainty assigned by TRC = 0.03 mol/l; TRC
ρc3.802mol/lN/ABeattie, Edwards, et al., 1949Uncertainty assigned by TRC = 0.1 mol/l; TRC
Quantity Value Units Method Reference Comment
Δvap19.99kJ/molN/AMajer and Svoboda, 1985 

Enthalpy of vaporization

ΔvapH (kJ/mol) Temperature (K) Method Reference Comment
21.297261.44N/AAston, Kennedy, et al., 1940, 2P = 101.325 kPa; DH
21.3261.3N/AMajer and Svoboda, 1985 
21.5318.N/ALim, Park, et al., 1999Based on data from 303. to 333. K.; AC
22.4265.AStephenson and Malanowski, 1987Based on data from 186. to 280. K.; AC
26.9172.AStephenson and Malanowski, 1987Based on data from 121. to 187. K.; AC
21.9278.AStephenson and Malanowski, 1987Based on data from 263. to 306. K.; AC
21.4316.AStephenson and Malanowski, 1987Based on data from 301. to 366. K.; AC
21.6376.AStephenson and Malanowski, 1987Based on data from 361. to 408. K.; AC
21.6292.N/ASteele, Poling, et al., 1976Based on data from 277. to 344. K. See also Boublik, Fried, et al., 1984.; AC
21.3286.N/AReid, 1972AC
21. ± 3.261.44VAston, Kennedy, et al., 1940, 3ALS
22.6247.N/AAston, Kennedy, et al., 1940, 2Based on data from 188. to 262. K. See also Boublik, Fried, et al., 1984.; AC

Entropy of vaporization

ΔvapS (J/mol*K) Temperature (K) Reference Comment
81.46261.44Aston, Kennedy, et al., 1940, 2P; DH

Antoine Equation Parameters

log10(P) = A − (B / (T + C))
    P = vapor pressure (bar)
    T = temperature (K)

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Temperature (K) A B C Reference Comment
261.31 to 408.124.32811132.1080.918Das, Reed, et al., 1973Coefficents calculated by NIST from author's data.
188.06 to 261.543.94417912.141-29.808Aston, Kennedy, et al., 1940, 2Coefficents calculated by NIST from author's data.

Enthalpy of fusion

ΔfusH (kJ/mol) Temperature (K) Reference Comment
4.540113.74Aston, Kennedy, et al., 1940, 2DH
4.49113.7Perkins and Magee, 2009AC
4.56113.7Domalski and Hearing, 1996AC
4.498113.2Parks, Shomate, et al., 1937, 2DH

Entropy of fusion

ΔfusS (J/mol*K) Temperature (K) Reference Comment
39.92113.74Aston, Kennedy, et al., 1940, 2DH
39.73113.2Parks, Shomate, et al., 1937, 2DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


Gas phase ion energetics data

Go To: Top, Phase change data, Ion clustering data, References, Notes

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, Phase change data, Gas phase ion energetics data, Ion clustering data, Notes

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

Younglove and Ely, 1987
Younglove, B.A.; Ely, J.F., Thermophysical Properties of Fluids II. Methane, Ethane, Propane, Isobutane, and Normal Butane, J. Phys. Chem. Ref. Data, 1987, 16, 577. [all data]

Goodwin and Haynes, 1982
Goodwin, R.D.; Haynes, W.M., Thermophysical Properties of Propane from 85 to 700 K at Pressures to 70 MPa, NBS Monogr. (U. S.) No. 170, 249 pp., 1982. [all data]

Aston, Kennedy, et al., 1940
Aston, J.G.; Kennedy, R.M.; Schumann, S.C., The Heat Capacity and Entropy of Fusion and Vaporization and the Vapor Pressure of Isobutane, J. Am. Chem. Soc., 1940, 62, 2059. [all data]

Parks, Shomate, et al., 1937
Parks, G.S.; Shomate, C.H.; Kennedy, W.D.; Crawford, B.L., The entropies of n-butane and isobutane with some heat capacity data for isobutane, J. Chem. Phys., 1937, 5, 359-63. [all data]

Daubert, 1996
Daubert, T.E., Vapor-Liquid Critical Properties of Elements and Compounds. 5. Branched Alkanes and Cycloalkanes, J. Chem. Eng. Data, 1996, 41, 365-372. [all data]

Levelt Sengers, Kamgar-Parsi, et al., 1983
Levelt Sengers, J.M.H.; Kamgar-Parsi, B.; Sengers, J.V., Thermodnamic Properties of Isobutane in the Critical Region, J. Chem. Eng. Data, 1983, 28, 354-362. [all data]

Waxman and Gallagher, 1983
Waxman, M.; Gallagher, J.S., Thermodynamic Properties of Isobutane for Temperatures from 250 to 600 K and Pressures from 0.1 to 40 MPa, J. Chem. Eng. Data, 1983, 28, 224. [all data]

Beattie, Edwards, et al., 1949
Beattie, J.A.; Edwards, D.G.; Marple, S., The Vapor Pressure, Orthobaric Liquid Density, and Critical Constants of Isobutane, J. Chem. Phys., 1949, 17, 576. [all data]

Majer and Svoboda, 1985
Majer, V.; Svoboda, V., Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation, Blackwell Scientific Publications, Oxford, 1985, 300. [all data]

Aston, Kennedy, et al., 1940, 2
Aston, J.G.; Kennedy, R.M.; Schumann, S.C., The heat capacity and entropy, heats of fusion and vaporization and the vapor pressure of isobutane, J. Am. Chem. Soc., 1940, 62, 2059-2063. [all data]

Lim, Park, et al., 1999
Lim, Jong Sung; Park, Ji-Young; Lee, Byung-Gwon; Lee, Youn-Woo; Kim, Jae-Duck, Phase Equilibria of CFC Alternative Refrigerant Mixtures: Binary Systems of Isobutane + 1,1,1,2-Tetrafluoroethane, + 1,1-Difluoroethane, and + Difluoromethane, J. Chem. Eng. Data, 1999, 44, 6, 1226-1230, https://doi.org/10.1021/je9900777 . [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Steele, Poling, et al., 1976
Steele, Kevin; Poling, Bruce E.; Manley, David B., Vapor pressures for the system 1-butene, isobutane, and 1,3-butadiene, J. Chem. Eng. Data, 1976, 21, 4, 399-403, https://doi.org/10.1021/je60071a006 . [all data]

Boublik, Fried, et al., 1984
Boublik, T.; Fried, V.; Hala, E., The Vapour Pressures of Pure Substances: Selected Values of the Temperature Dependence of the Vapour Pressures of Some Pure Substances in the Normal and Low Pressure Region, 2nd ed., Elsevier, New York, 1984, 972. [all data]

Reid, 1972
Reid, Robert C., Handbook on vapor pressure and heats of vaporization of hydrocarbons and related compounds, R. C. Wilhort and B. J. Zwolinski, Texas A Research Foundation. College Station, Texas(1971). 329 pages.$10.00, AIChE J., 1972, 18, 6, 1278-1278, https://doi.org/10.1002/aic.690180637 . [all data]

Aston, Kennedy, et al., 1940, 3
Aston, J.G.; Kennedy, R.M.; Schumann, S.C., The heat capacity and entropy, heats of fusion and vaporization and the vapor pressure of isobutane, J. Am. Chem. Soc., 1940, 62, 2059-20. [all data]

Das, Reed, et al., 1973
Das, T.R.; Reed, C.O., Jr.; Eubank, P.T., PVT Surface and Thermodynamic Properties of Isobutane, J. Chem. Eng. Data, 1973, 18, 3, 253-262, https://doi.org/10.1021/je60058a001 . [all data]

Perkins and Magee, 2009
Perkins, Richard A.; Magee, Joseph W., Molar Heat Capacity at Constant Volume for Isobutane at Temperatures from (114 to 345) K and at Pressures to 35 MPa «8224» «8225», J. Chem. Eng. Data, 2009, 54, 9, 2646-2655, https://doi.org/10.1021/je9001575 . [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

Parks, Shomate, et al., 1937, 2
Parks, G.S.; Shomate, C.H.; Kennedy, W.D.; Crawford, B.L., Jr., The entropies of n-butane and isobutane, with some heat capacity data for isobutane, J. Chem. Phys., 1937, 5, 359-363. [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]

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, Phase change data, Gas phase ion energetics data, Ion clustering data, References