Butane, 2,2-dimethyl-
- Formula: C6H14
- Molecular weight: 86.1754
- 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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Condensed phase thermochemistry data
Go To: Top, Phase change data, Reaction thermochemistry data, Gas phase ion energetics 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:
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 |
---|---|---|---|---|---|
ΔfH°liquid | -213.4 ± 0.96 | kJ/mol | Ccb | Prosen and Rossini, 1945 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°liquid | -4148.5 ± 0.88 | kJ/mol | Ccb | Prosen and Rossini, 1945 | Corresponding ΔfHºliquid = -213.3 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°liquid | 272.00 | J/mol*K | N/A | Douslin and Huffman, 1946 | DH |
S°liquid | 272.5 | J/mol*K | N/A | Kilpatrick and Pitzer, 1946 | DH |
S°liquid | 269.4 | J/mol*K | N/A | Stull, 1937 | Extrapolation below 90 K, 17.76 cal/mol*K.; DH |
Constant pressure heat capacity of liquid
Cp,liquid (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
189.67 | 298.15 | Ohnishi, Fujihara, et al., 1989 | DH |
191.88 | 298.15 | Costas, Huu, et al., 1988 | DH |
191.88 | 298.15 | Perez-Casas, Aicart, et al., 1988 | DH |
189.44 | 298.15 | Benson and D'Arcy, 1986 | DH |
189.14 | 298.15 | Aicart, Kumaran, et al., 1983 | DH |
189.14 | 298.15 | Benson, D'Arcy, et al., 1983 | DH |
191.5 | 300. | Auerbach, Sage, et al., 1950 | T = 300 to 366 K. Cp given as 0.5312 Btu/lb*R at 80°F.; DH |
188.74 | 298.15 | Douslin and Huffman, 1946 | T = 13 to 300 K.; DH |
186.9 | 290. | Kilpatrick and Pitzer, 1946 | T = 20 to 290 K.; DH |
183.18 | 298.1 | Stull, 1937 | T = 90 to 320 K.; DH |
Phase change 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:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
CAL - James S. Chickos, William E. Acree, Jr., Joel F. Liebman, Students of Chem 202 (Introduction to the Literature of Chemistry), University of Missouri -- St. Louis
DH - Eugene S. Domalski and Elizabeth D. Hearing
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Tboil | 322.9 ± 0.1 | K | AVG | N/A | Average of 46 out of 54 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 173. ± 2. | K | AVG | N/A | Average of 24 out of 28 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 174. ± 2. | K | AVG | N/A | Average of 6 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 489.0 ± 0.5 | K | AVG | N/A | Average of 7 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 31.0 ± 0.2 | bar | N/A | Daubert, 1996 | |
Pc | 31.0236 | bar | N/A | Genco, Teja, et al., 1980 | Uncertainty assigned by TRC = 0.05 bar; TRC |
Pc | 31.02 | bar | N/A | Kay and Young, 1975 | Uncertainty assigned by TRC = 0.03 bar; TRC |
Pc | 31.0764 | bar | N/A | Kay, 1946 | Uncertainty assigned by TRC = 0.1013 bar; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Vc | 0.358 | l/mol | N/A | Daubert, 1996 | |
Vc | 0.358 | l/mol | N/A | Genco, Teja, et al., 1980 | Uncertainty assigned by TRC = 0.001 l/mol; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 2.80 ± 0.02 | mol/l | N/A | Daubert, 1996 | |
ρc | 2.79 | mol/l | N/A | Kay, 1946 | Uncertainty assigned by TRC = 0.02 mol/l; by extrapolation of rectilinear diameter to Tc; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 27.93 | kJ/mol | N/A | Majer and Svoboda, 1985 | |
ΔvapH° | 27.7 | kJ/mol | N/A | Reid, 1972 | AC |
ΔvapH° | 27.68 | kJ/mol | C | Osborne and Ginnings, 1947 | ALS |
Enthalpy of vaporization
ΔvapH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
26.31 | 322.9 | N/A | Majer and Svoboda, 1985 | |
28.7 | 288. | N/A | Nicolini and Laffitte, 1949 | Based on data from 273. to 318. K. See also Boublik, Fried, et al., 1984.; AC |
27.8 ± 0.1 | 296. | C | Waddington and Douslin, 1947 | AC |
26.3 ± 0.1 | 323. | C | Waddington and Douslin, 1947 | AC |
29.2 | 274. | N/A | Kilpatrick and Pitzer, 1946 | Based on data from 211. to 289. K.; AC |
28.3 | 303. | MM | Willingham, Taylor, et al., 1945 | Based on data from 288. to 323. K.; AC |
Enthalpy of vaporization
ΔvapH =
A exp(-βTr) (1 − Tr)β
ΔvapH =
Enthalpy of vaporization (at saturation pressure)
(kJ/mol)
Tr = reduced temperature (T / Tc)
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Temperature (K) | A (kJ/mol) | β | Tc (K) | Reference | Comment |
---|---|---|---|---|---|
296. to 323. | 41.92 | 0.2675 | 488.7 | Majer and Svoboda, 1985 |
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 |
---|---|---|---|---|---|
210.99 to 289.38 | 3.7382 | 1022.204 | -49.529 | Kilpatrick and Pitzer, 1946 | Coefficents calculated by NIST from author's data. |
288.53 to 323.68 | 3.87973 | 1081.176 | -43.807 | Williamham, Taylor, et al., 1945 |
Enthalpy of fusion
ΔfusH (kJ/mol) | Temperature (K) | Reference | Comment |
---|---|---|---|
0.58 | 174.3 | Domalski and Hearing, 1996 | AC |
Entropy of fusion
ΔfusS (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
42.57 | 126.8 | Domalski and Hearing, 1996 | CAL |
2.02 | 140.8 | ||
3.31 | 174.3 |
Enthalpy of phase transition
ΔHtrs (kJ/mol) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|---|
5.410 | 126.81 | crystaline, III | crystaline, II | Douslin and Huffman, 1946 | DH |
0.2853 | 140.79 | crystaline, II | crystaline, I | Douslin and Huffman, 1946 | DH |
0.5791 | 174.28 | crystaline, I | liquid | Douslin and Huffman, 1946 | DH |
5.394 | 126.81 | crystaline, III | crystaline, II | Kilpatrick and Pitzer, 1946 | DH |
0.283 | 140.88 | crystaline, II | crystaline, I | Kilpatrick and Pitzer, 1946 | DH |
0.579 | 174.66 | crystaline, I | liquid | Kilpatrick and Pitzer, 1946 | DH |
4.581 | 127.11 | crystaline, II | crystaline, I | Stull, 1937 | DH |
0.464 | 172.13 | crystaline, I | liquid | Stull, 1937 | DH |
Entropy of phase transition
ΔStrs (J/mol*K) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
---|---|---|---|---|---|
42.66 | 126.81 | crystaline, III | crystaline, II | Douslin and Huffman, 1946 | DH |
2.03 | 140.79 | crystaline, II | crystaline, I | Douslin and Huffman, 1946 | DH |
3.32 | 174.28 | crystaline, I | liquid | Douslin and Huffman, 1946 | DH |
42.5 | 126.81 | crystaline, III | crystaline, II | Kilpatrick and Pitzer, 1946 | DH |
2.01 | 140.88 | crystaline, II | crystaline, I | Kilpatrick and Pitzer, 1946 | DH |
3.33 | 174.66 | crystaline, I | liquid | Kilpatrick and Pitzer, 1946 | DH |
36.04 | 127.11 | crystaline, II | crystaline, I | Stull, 1937 | DH |
2.70 | 172.13 | crystaline, I | liquid | Stull, 1937 | 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 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
By formula: H2 + C6H12 = C6H14
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -125.8 ± 0.53 | kJ/mol | Chyd | Rogers, Crooks, et al., 1987 | liquid phase |
ΔrH° | -125.9 ± 0.63 | kJ/mol | Chyd | Dolliver, Gresham, et al., 1937 | gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -126.95 ± 0.63 kJ/mol; AT 355 °K |
By formula: C6H14 = C6H14
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -14.6 ± 0.75 | kJ/mol | Ciso | Prosen and Rossini, 1941 | liquid phase; Calculated from ΔHc |
By formula: C6H14 = H2 + C6H12
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 125.9 ± 0.8 | kJ/mol | Cm | Kennedy, Shomate, et al., 1938 | liquid phase |
Gas phase ion energetics data
Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry 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:
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, Condensed phase thermochemistry data, Phase change 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.
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]
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]
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]
Genco, Teja, et al., 1980
Genco, J.M.; Teja, A.S.; Kay, W.B.,
Study of the critical and azeotropic behavior of binary mixtures I critical states of perfluoromethylcyclohexane + isomeric hexane systems,
J. Chem. Eng. Data, 1980, 25, 350. [all data]
Kay and Young, 1975
Kay, W.B.; Young, C.L.,
Gas-liquid critical properties. Tetradecafluoromethylcyclohexane( perfluoromethylcyclohexane)-2,2-dimethylbutane,
Int. DATA Ser., Sel. Data Mixtures, Ser. A, 1975, No. 1, 58. [all data]
Kay, 1946
Kay, W.B.,
The Vapor Pressures and Saturated Liquid and Vapor Densities of the Isomeric Hexanes,
J. Am. Chem. Soc., 1946, 68, 1336. [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]
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]
Osborne and Ginnings, 1947
Osborne, N.S.; Ginnings, D.C.,
Measurements of heat of vaporization and heat capacity of a number of hydrocarbons,
J. Res. NBS, 1947, 39, 453-477. [all data]
Nicolini and Laffitte, 1949
Nicolini, E.; Laffitte, P.,
Compt. Rend., 1949, 229, 757. [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]
Waddington and Douslin, 1947
Waddington, Guy; Douslin, Donald R.,
Experimental Vapor Heat Capacities and Heats of Vaporization of n-Hexane and 2,2-Dimethylbutane 1,
J. Am. Chem. Soc., 1947, 69, 10, 2275-2279, https://doi.org/10.1021/ja01202a011
. [all data]
Willingham, Taylor, et al., 1945
Willingham, C.B.; Taylor, W.J.; Pignocco, J.M.; Rossini, F.D.,
Vapor pressures and boiling points of some paraffin, alkylcyclopentane, alkylcyclohexane, and alkylbenzene hydrocarbons,
J. RES. NATL. BUR. STAN., 1945, 35, 3, 219-17, https://doi.org/10.6028/jres.035.009
. [all data]
Williamham, Taylor, et al., 1945
Williamham, C.B.; Taylor, W.J.; Pignocco, J.M.; Rossini, F.D.,
Vapor Pressures and Boiling Points of Some Paraffin, Alkylcyclopentane, Alkylcyclohexane, and Alkylbenzene Hydrocarbons,
J. Res. Natl. Bur. Stand. (U.S.), 1945, 35, 3, 219-244, https://doi.org/10.6028/jres.035.009
. [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]
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
Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy Cp,liquid Constant pressure heat capacity of liquid Pc Critical pressure S°liquid Entropy of liquid at standard conditions Tboil Boiling point Tc Critical temperature Tfus Fusion (melting) point Ttriple Triple point temperature Vc Critical volume ΔHtrs Enthalpy of phase transition ΔStrs Entropy of phase transition ΔcH°liquid Enthalpy of combustion of liquid at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions ΔfusH Enthalpy of fusion ΔfusS Entropy of fusion ΔrH° Enthalpy of reaction at standard conditions ΔvapH Enthalpy of vaporization ΔvapH° Enthalpy of vaporization at standard conditions ρc Critical density - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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