Butane, 2,2-dimethyl-

Formula: C₆H₁₄
Molecular weight: 86.1754
IUPAC Standard InChI: InChI=1S/C6H14/c1-5-6(2,3)4/h5H2,1-4H3
IUPAC Standard InChIKey: HNRMPXKDFBEGFZ-UHFFFAOYSA-N
CAS Registry Number: 75-83-2
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: Neohexane; 2,2-Dimethylbutane; (CH3)3CCH2CH3; UN 1208
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Gas phase thermochemistry data

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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
Δ_fH°_gas	-44.35 ± 0.23	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Quantity	Value	Units	Method	Reference	Comment
S°_gas	85.72 ± 0.20	cal/mol*K	N/A	Kilpatrick J.E., 1946	The entropy values S(296.05 K)=357.19 and S(322.85 K)=369.87 J/mol*K were calculated by [ Scott D.W., 1974] from the experimental data [ Douslin D.R., 1946].; GT

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
24.250	200.	Scott D.W., 1974, 2	Recommended values were obtained from the consistent correlation scheme for alkanes [ Scott D.W., 1974, Scott D.W., 1974, 2]. This approach gives a better agreement with experimental data than the statistical thermodynamics calculation [ Pitzer K.S., 1946] (see also [ Waddington G., 1949]).; GT
31.329	273.15
33.81 ± 0.07	298.15
34.001	300.
43.769	400.
52.660	500.
60.500	600.
67.299	700.
73.301	800.
78.499	900.
83.200	1000.
87.299	1100.
90.901	1200.
94.001	1300.
97.000	1400.
100.00	1500.

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
38.100 ± 0.076	341.55	Waddington G., 1947	GT
39.250 ± 0.079	353.20
41.501 ± 0.084	376.05
44.950 ± 0.091	412.40
48.329 ± 0.096	449.40

Condensed phase thermochemistry data

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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
Δ_fH°_liquid	-51.01 ± 0.23	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-991.52 ± 0.21	kcal/mol	Ccb	Prosen and Rossini, 1945	Corresponding Δ_fHº_liquid = -50.99 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	65.010	cal/mol*K	N/A	Douslin and Huffman, 1946	DH
S°_liquid	65.13	cal/mol*K	N/A	Kilpatrick and Pitzer, 1946	DH
S°_liquid	64.39	cal/mol*K	N/A	Stull, 1937	Extrapolation below 90 K, 17.76 cal/mol*K.; DH

Constant pressure heat capacity of liquid

C_p,liquid (cal/mol*K)	Temperature (K)	Reference	Comment
45.332	298.15	Ohnishi, Fujihara, et al., 1989	DH
45.860	298.15	Costas, Huu, et al., 1988	DH
45.860	298.15	Perez-Casas, Aicart, et al., 1988	DH
45.277	298.15	Benson and D'Arcy, 1986	DH
45.206	298.15	Aicart, Kumaran, et al., 1983	DH
45.206	298.15	Benson, D'Arcy, et al., 1983	DH
45.77	300.	Auerbach, Sage, et al., 1950	T = 300 to 366 K. Cp given as 0.5312 Btu/lb*R at 80°F.; DH
45.110	298.15	Douslin and Huffman, 1946	T = 13 to 300 K.; DH
44.67	290.	Kilpatrick and Pitzer, 1946	T = 20 to 290 K.; DH
43.781	298.1	Stull, 1937	T = 90 to 320 K.; DH

Reaction thermochemistry data

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Data compiled by: 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

+ = Butane, 2,2-dimethyl-

By formula: H₂ + C₆H₁₂ = C₆H₁₄

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-30.07 ± 0.13	kcal/mol	Chyd	Rogers, Crooks, et al., 1987	liquid phase
Δ_rH°	-30.10 ± 0.15	kcal/mol	Chyd	Dolliver, Gresham, et al., 1937	gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -30.34 ± 0.15 kcal/mol; AT 355 °K

= Butane, 2,2-dimethyl-

By formula: C₆H₁₄ = C₆H₁₄

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-3.49 ± 0.18	kcal/mol	Ciso	Prosen and Rossini, 1941	liquid phase; Calculated from ΔHc

Butane, 2,2-dimethyl- = +

By formula: C₆H₁₄ = H₂ + C₆H₁₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	30.1 ± 0.2	kcal/mol	Cm	Kennedy, Shomate, et al., 1938	liquid phase

Gas phase ion energetics data

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Data compiled as indicated in comments:
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

Ionization energy determinations

IE (eV)	Method	Reference	Comment
10.07	EST	Luo and Pacey, 1992	LL
9.79	EQ	Lias, Ausloos, et al., 1976	LLK
10.06	PI	Watanabe, Nakayama, et al., 1962	RDSH

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C₄H₈⁺	10.23 ± 0.015	C₂H₆	PI	Steiner, Giese, et al., 1961	RDSH
C₄H₉⁺	10.60 ± 0.025	C₂H₅	PI	Steiner, Giese, et al., 1961	RDSH
C₅H₁₀⁺	10.28 ± 0.02	CH₄	PI	Steiner, Giese, et al., 1961	RDSH
C₅H₁₁⁺	10.555 ± 0.045	CH₃	PI	Steiner, Giese, et al., 1961	RDSH

References

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

Prosen and Rossini, 1945
Prosen, E.J.; Rossini, F.D., Heats of combustion and formation of the paraffin hydrocarbons at 25° C, J. Res. NBS, 1945, 263-267. [all data]

Kilpatrick J.E., 1946
Kilpatrick J.E., The thermodynamics of 2,2-dimethylbutane, including the heat capacity, heats of transition, fusion and vaporization and the entropy, J. Am. Chem. Soc., 1946, 68, 1066-1072. [all data]

Scott D.W., 1974
Scott D.W., Correlation of the chemical thermodynamic properties of alkane hydrocarbons, J. Chem. Phys., 1974, 60, 3144-3165. [all data]

Douslin D.R., 1946
Douslin D.R., Low-temperature thermal data on the five isomeric hexanes, J. Am. Chem. Soc., 1946, 68, 1704-1708. [all data]

Scott D.W., 1974, 2
Scott D.W., Chemical Thermodynamic Properties of Hydrocarbons and Related Substances. Properties of the Alkane Hydrocarbons, C1 through C10 in the Ideal Gas State from 0 to 1500 K. U.S. Bureau of Mines, Bulletin 666, 1974. [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]

Waddington G., 1949
Waddington G., Experimental vapor heat capacities and heats of vaporization of 2-methylpentane, 3-methylpentane, and 2,3-dimethylbutane, J. Am. Chem. Soc., 1949, 71, 3902-3906. [all data]

Waddington G., 1947
Waddington G., Experimental vapor heat capacities and heats of vaporization of n-hexane and 2,2-dimethylbutane, J. Am. Chem. Soc., 1947, 69, 2275-2279. [all data]

Douslin and Huffman, 1946
Douslin, D.R.; Huffman, H.M., Low-temperature thermal data on the five isometric hexanes, J. Am. Chem. Soc., 1946, 68, 1704-1708. [all data]

Kilpatrick and Pitzer, 1946
Kilpatrick, J.E.; Pitzer, K.S., The thermodynamics of 2,2-dimethylbutane, including the heat capacity, heats of transitions, fusion and vaporization and the entropy, J. Am. Chem. Soc., 1946, 68, 1066-1072. [all data]

Stull, 1937
Stull, D.R., A semi-micro calorimeter for measuring heat capacities at low temperatures, J. Am. Chem. Soc., 1937, 59, 2726-2733. [all data]

Ohnishi, Fujihara, et al., 1989
Ohnishi, K.; Fujihara, I.; Murakami, S., Thermodynamic properties of decalins mixed with hexane isomers at 298.15K. 1. Excess enthalpies and excess isobaric heat capacities, Fluid Phase Equilib., 1989, 46, 59-72. [all data]

Costas, Huu, et al., 1988
Costas, M.; Huu, V.T.; Patterson, D.; Caceres-Alonso, M.; Tardajos, G.; Aicart, E., Liquid structure and second-order mixing functions for l-chloronaphthalene with linear and branched alkanes, J. Chem. Soc., Faraday Trans., 1988, 1 84(5), 1603-1616. [all data]

Perez-Casas, Aicart, et al., 1988
Perez-Casas, S.; Aicart, E.; Trojo, L.M.; Costas, M., Excess heat capacity. Chlorobenzene-2,2,4,4,6,8,8-heptamethylnonane, Int. Data Ser., Sel. Data Mixtures, 1988, (2)A, 123. [all data]

Benson and D'Arcy, 1986
Benson, G.C.; D'Arcy, P.J., Heat capacities of binary mixtures of n-octane with each of the hexane isomers at 298.15 K, Can. J. Chem., 1986, 64, 2139-2141. [all data]

Aicart, Kumaran, et al., 1983
Aicart, E.; Kumaran, M.K.; Halpin, C.J.; Benson, G.C., Ultrasonic speeds and isentropic compressibilities of 2-methylpentan-1-ol with hexane isomers at 298.15 K, J. Chem. Thermodynam., 1983, 15, 1189-1197. [all data]

Benson, D'Arcy, et al., 1983
Benson, G.C.; D'Arcy, P.J.; Sugamori, M.E., Heat capacities of binary mixtures of 1-hexanol with hexane isomers at 298.15 K, Thermochim. Acta, 1983, 71, 161-166. [all data]

Auerbach, Sage, et al., 1950
Auerbach, C.E.; Sage, B.H.; Lacey, W.N., Isobaric heat capacities at bubble point, Ind. Eng. Chem., 1950, 42, 110-113. [all data]

Rogers, Crooks, et al., 1987
Rogers, D.W.; Crooks, E.; Dejroongruang, K., Enthalpies of hydrogenation of the hexenes, J. Chem. Thermodyn., 1987, 19, 1209-1215. [all data]

Dolliver, Gresham, et al., 1937
Dolliver, M.a.; Gresham, T.L.; Kistiakowsky, G.B.; Vaughan, W.E., Heats of organic reactions. V. Heats of hydrogenation of various hydrocarbons, J. Am. Chem. Soc., 1937, 59, 831-841. [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]

Prosen and Rossini, 1941
Prosen, E.J.R.; Rossini, F.D., Heats of isomerization of the five hexanes, J. Res. NBS, 1941, 27, 289-310. [all data]

Kennedy, Shomate, et al., 1938
Kennedy, Wm.D.; Shomate, C.H.; Parks, G.P., Thermal data on organic compounds. XVIII. The heat capacity of and entropy of t-butylethylene, J. Am. Chem. Soc., 1938, 60, 1507-1509. [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]

Lias, Ausloos, et al., 1976
Lias, S.G.; Ausloos, P.; Horvath, Z., Charge transfer reactions in alkane and cycloalkane systems. Estimated ionization potentials, Int. J. Chem. Kinet., 1976, 8, 725. [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]

Notes

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Symbols used in this document:

AE	Appearance energy
C_p,gas	Constant pressure heat capacity of gas
C_p,liquid	Constant pressure heat capacity of liquid
S°_gas	Entropy of gas at standard conditions
S°_liquid	Entropy of liquid at standard conditions
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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