Butane, 2-methyl-
- Formula: C5H12
- Molecular weight: 72.1488
- IUPAC Standard InChI: InChI=1S/C5H12/c1-4-5(2)3/h5H,4H2,1-3H3
- IUPAC Standard InChIKey: QWTDNUCVQCZILF-UHFFFAOYSA-N
- CAS Registry Number: 78-78-4
- 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: iso-Pentane; 1,1,2-Trimethylethane; 2-Methylbutane; iso-C5H12; Ethyldimethylmethane; Isoamylhydride; Exxsol isopentane S; 1,1-Dimethylpropane; Methylbutane; NSC 119476
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Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry 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:
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 |
|---|---|---|---|---|---|
| ΔfH°gas | -153.7 ± 0.59 | kJ/mol | Ccb | Good, 1970 | ALS |
| ΔfH°gas | -154.1 ± 0.96 | kJ/mol | Cm | Pilcher and Chadwick, 1967 | ALS |
| ΔfH°gas | -154.5 ± 0.84 | kJ/mol | Ccb | Prosen and Rossini, 1945 | ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°gas | -3528.4 ± 0.92 | kJ/mol | Cm | Pilcher and Chadwick, 1967 | Corresponding ΔfHºgas = -154.1 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
| ΔcH°gas | -3528.6 ± 0.63 | kJ/mol | Cm | Knowlton and Rossini, 1939 | Corresponding ΔfHºgas = -153.9 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
| ΔcH°gas | -3527.6 ± 3.5 | kJ/mol | Ccb | Roth and Pahlke, 1936 | Reanalyzed by Cox and Pilcher, 1970, Original value = -3529.0 kJ/mol; Corresponding ΔfHºgas = -155.0 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 |
|---|---|---|---|
| 84.94 | 200. | Scott D.W., 1974 | Recommended values were obtained from the consistent correlation scheme for alkanes [ Scott D.W., 1974, 2, Scott D.W., 1974]. This approach gives a better agreement with experimental data than the statistical thermodynamics calculations [ Pitzer K.S., 1946, Scott D.W., 1951].; GT |
| 110.37 | 273.15 | ||
| 118.9 ± 0.4 | 298.15 | ||
| 119.50 | 300. | ||
| 152.88 | 400. | ||
| 183.26 | 500. | ||
| 210.04 | 600. | ||
| 233.05 | 700. | ||
| 253.13 | 800. | ||
| 270.70 | 900. | ||
| 286.19 | 1000. | ||
| 299.57 | 1100. | ||
| 311.29 | 1200. | ||
| 322.17 | 1300. | ||
| 330.54 | 1400. | ||
| 338.90 | 1500. |
Constant pressure heat capacity of gas
| Cp,gas (J/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 125.31 ± 0.37 | 317.20 | Scott D.W., 1951 | GT |
| 139.12 ± 0.42 | 358.15 | ||
| 153.64 ± 0.46 | 402.30 | ||
| 168.36 ± 0.51 | 449.20 | ||
| 179.62 ± 0.54 | 487.05 |
Condensed phase thermochemistry data
Go To: Top, Gas phase thermochemistry 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:
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 | -178.2 ± 0.88 | kJ/mol | Ccb | Good, 1970 | Reanalyzed by Pedley, Naylor, et al., 1986, Original value = -178.9 ± 0.59 kJ/mol; ALS |
| ΔfH°liquid | -179.3 ± 0.84 | kJ/mol | Ccb | Prosen and Rossini, 1945 | ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°liquid | -3504.4 ± 0.84 | kJ/mol | Ccb | Good, 1970 | Reanalyzed by Pedley, Naylor, et al., 1986, Original value = -3503.6 ± 0.46 kJ/mol; Corresponding ΔfHºliquid = -178.2 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
| ΔcH°liquid | -3503.3 ± 0.75 | kJ/mol | Ccb | Prosen and Rossini, 1945 | Corresponding ΔfHºliquid = -179.3 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| S°liquid | 260.41 | J/mol*K | N/A | Guthrie and Huffman, 1943 | DH |
| S°liquid | 261.04 | J/mol*K | N/A | Schumann, Aston, et al., 1942 | DH |
| S°liquid | 254.4 | J/mol*K | N/A | Parks, Huffman, et al., 1930 | Extrapolation below 90 K, 57.49 J/mol*K.; DH |
Constant pressure heat capacity of liquid
| Cp,liquid (J/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 164.5 | 298.3 | Czarnota, 1988 | T = 289 to 299 K. p = 0.1 MPa. Unsmoothed experimental datum. Cp values provided over the pressure range 0.1 to 820 MPa.; DH |
| 164.85 | 298.15 | Guthrie and Huffman, 1943 | T = 13 to 300 K.; DH |
| 169.41 | 290. | Schumann, Aston, et al., 1942 | T = 20 to 290 K.; DH |
| 157.3 | 275.8 | Parks, Huffman, et al., 1930 | T = 80 to 276 K. Value is unsmoothed experimental datum.; DH |
Reaction thermochemistry data
Go To: Top, Gas phase thermochemistry data, Condensed phase 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 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 + C5H10 = C5H12
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -126.95 | kJ/mol | Chyd | Dolliver, Gresham, et al., 1937 | gas phase; At 355 °K |
| ΔrH° | -118.2 ± 0.42 | kJ/mol | Chyd | Kistiakowsky, Ruhoff, et al., 1936 | gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -119.2 ± 1.5 kJ/mol; At 355 K |
+
=
By formula: H2 + C5H10 = C5H12
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -126.3 ± 0.3 | kJ/mol | Chyd | Dolliver, Gresham, et al., 1937 | gas phase; Reanalyzed by Cox and Pilcher, 1970, Original value = -126.9 ± 0.3 kJ/mol; At 355 °K |
=
By formula: C5H12 = C5H12
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -7.786 | kJ/mol | Eqk | Pines, Kvetinskas, et al., 1945 | gas phase; Heat of isomerization |
+
=
By formula: H2 + C5H10 = C5H12
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -111.6 ± 0.3 | kJ/mol | Chyd | Kistiakowsky, Ruhoff, et al., 1936 | gas phase |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Good, 1970
Good, W.D.,
The enthalpies of combustion and formation of the isomeric pentanes,
J. Chem. Thermodyn., 1970, 2, 237-244. [all data]
Pilcher and Chadwick, 1967
Pilcher, G.; Chadwick, J.D.M.,
Measurements of heats of combustion by flame calorimetry. Part 4.-n-Pentane, isopentane, neopentane,
Trans. Faraday Soc., 1967, 63, 2357-2361. [all data]
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]
Knowlton and Rossini, 1939
Knowlton, J.W.; Rossini, F.D.,
Heats of combustion of tetramethylmethane and 2-methylbutane,
J. Res. NBS, 1939, 22, 415-424. [all data]
Roth and Pahlke, 1936
Roth, W.A.; Pahlke, H.,
Sekundare eichsubstanz fur verbrennungscalorimeter fur gase und dampfe. Die verbrennungswarme von isopentandampf,
Angew. Chem., 1936, 49, 618-619. [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]
Scott D.W., 1974
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]
Scott D.W., 1974, 2
Scott D.W.,
Correlation of the chemical thermodynamic properties of alkane hydrocarbons,
J. Chem. Phys., 1974, 60, 3144-3165. [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]
Scott D.W., 1951
Scott D.W.,
Rotational isomerism and thermodynamic functions of 2-methylbutane and 2,3-dimethylbutane. Vapor heat capacity and heat of vaporization of 2-methylbutane,
J. Am. Chem. Soc., 1951, 73, 1707-1712. [all data]
Pedley, Naylor, et al., 1986
Pedley, J.B.; Naylor, R.D.; Kirby, S.P.,
Thermochemical Data of Organic Compounds, Chapman and Hall, New York, 1986, 1-792. [all data]
Guthrie and Huffman, 1943
Guthrie, G.B., Jr.; Huffman, H.M.,
Thermal data. XVI. The heat capacity and entropy of isopentane. The absence of a reported anomaly,
J. Am. Chem. Soc., 1943, 65, 1139-1143. [all data]
Schumann, Aston, et al., 1942
Schumann, S.C.; Aston, J.G.; Sagenkahn, M.,
The heat capacity and entropy, heats of fusion and vaporization and the vapor pressures of isopentane,
J. Am. Chem. Soc., 1942, 64, 1039-1043. [all data]
Parks, Huffman, et al., 1930
Parks, G.S.; Huffman, H.M.; Thomas, S.B.,
Thermal data on organic compounds. VI. The heat capacities, entropies and free energies of some saturated, non-benzenoid hydrocarbons,
J. Am. Chem. Soc., 1930, 52, 1032-1041. [all data]
Czarnota, 1988
Czarnota, I.,
Heat capacity of 2-methylbutane at high pressures,
J. Chem. Thermodynam., 1988, 20, 457-462. [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]
Kistiakowsky, Ruhoff, et al., 1936
Kistiakowsky, G.B.; Ruhoff, J.R.; Smith, H.A.; Vaughan, W.E.,
Heats of organic reactions. III. Hydrogenation of some higher olefins,
J. Am. Chem. Soc., 1936, 58, 137-145. [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]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, References
- Symbols used in this document:
Cp,gas Constant pressure heat capacity of gas Cp,liquid Constant pressure heat capacity of liquid S°liquid Entropy of liquid at standard conditions ΔcH°gas Enthalpy of combustion of gas at standard conditions ΔcH°liquid Enthalpy of combustion of liquid at standard conditions ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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