Heptane, 2-methyl-
- Formula: C8H18
- Molecular weight: 114.2285
- IUPAC Standard InChIKey: JVSWJIKNEAIKJW-UHFFFAOYSA-N
- CAS Registry Number: 592-27-8
- 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. - Isotopologues:
- Other names: 2-Methylheptane; (CH3)2CH(CH2)4CH3; Methylheptane
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Condensed phase thermochemistry data
Go To: Top, Phase change data, Gas phase ion energetics data, Mass spectrum (electron ionization), 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 | -255.2 ± 1.3 | kJ/mol | Ccb | Prosen and Rossini, 1945 | ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°liquid | -5465.5 ± 1.2 | kJ/mol | Ccb | Prosen and Rossini, 1945 | Corresponding ΔfHºliquid = -255.1 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
ΔcH°liquid | -5447.1 | kJ/mol | Ccb | Fajans, 1920 | Corresponding ΔfHºliquid = -273. kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
ΔcH°liquid | -5274.6 | kJ/mol | Ccb | Richards and Jesse, 1910 | At 293 K; Corresponding ΔfHºliquid = -446.0 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°liquid | 356.39 | J/mol*K | N/A | Messerly and Finke, 1971 | DH |
Constant pressure heat capacity of liquid
Cp,liquid (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
252.00 | 298.15 | Messerly and Finke, 1971 | T = 11 to 370 K.; DH |
251.58 | 298.15 | Osborne and Ginnings, 1947 | T = 283 to 318 K.; DH |
Phase change data
Go To: Top, Condensed phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), 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
AC - William E. Acree, Jr., James S. Chickos
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 |
---|---|---|---|---|---|
Tboil | 390.7 ± 0.8 | K | AVG | N/A | Average of 37 out of 38 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 163. ± 2. | K | AVG | N/A | Average of 14 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 160. ± 9. | K | AVG | N/A | Average of 10 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 559.7 ± 0.1 | K | N/A | Daubert, 1996 | |
Tc | 559.7 | K | N/A | Abara, Jennings, et al., 1988 | Uncertainty assigned by TRC = 0.2 K; TRC |
Tc | 559.6 | K | N/A | Majer and Svoboda, 1985 | |
Tc | 559.56 | K | N/A | McMicking and Kay, 1965 | Uncertainty assigned by TRC = 0.4 K; TRC |
Tc | 559.57 | K | N/A | Ambrose, Cox, et al., 1960 | Uncertainty assigned by TRC = 0.2 K; Visual, PRT, IPTS-48; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 25.0 ± 0.2 | bar | N/A | Daubert, 1996 | |
Pc | 25.00 | bar | N/A | Abara, Jennings, et al., 1988 | Uncertainty assigned by TRC = 0.40 bar; TRC |
Pc | 24.842 | bar | N/A | McMicking and Kay, 1965 | Uncertainty assigned by TRC = 0.4053 bar; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Vc | 0.488 | l/mol | N/A | Daubert, 1996 | |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 2.05 ± 0.02 | mol/l | N/A | Daubert, 1996 | |
ρc | 2.05 | mol/l | N/A | McMicking and Kay, 1965 | Uncertainty assigned by TRC = 0.04 mol/l; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 39. ± 5. | kJ/mol | AVG | N/A | Average of 6 values; Individual data points |
Reduced pressure boiling point
Tboil (K) | Pressure (bar) | Reference | Comment |
---|---|---|---|
389.2 | 1.01 | Aldrich Chemical Company Inc., 1990 | BS |
Enthalpy of vaporization
ΔvapH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
33.26 | 390.8 | N/A | Majer and Svoboda, 1985 | |
39.8 | 300. | A | Stephenson and Malanowski, 1987 | Based on data from 285. to 392. K.; AC |
41.6 | 268. | IP | Stephenson and Malanowski, 1987 | Based on data from 233. to 283. K. See also Osborn and Douslin, 1974.; AC |
38.7 ± 0.1 | 313. | C | Majer, Svoboda, et al., 1979 | AC |
37.3 ± 0.1 | 333. | C | Majer, Svoboda, et al., 1979 | AC |
36.0 ± 0.1 | 353. | C | Majer, Svoboda, et al., 1979 | AC |
38.1 | 330. | MM | Willingham, Taylor, et al., 1945 | Based on data from 315. to 391. 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 |
---|---|---|---|---|---|
298. to 353. | 57.87 | 0.2919 | 559.6 | 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 |
---|---|---|---|---|---|
233. to 283. | 4.84562 | 1718.531 | -29.682 | Osborn and Douslin, 1974 | Coefficents calculated by NIST from author's data. |
314.86 to 391.69 | 4.04227 | 1337.468 | -59.457 | Williamham, Taylor, et al., 1945 |
Enthalpy of fusion
ΔfusH (kJ/mol) | Temperature (K) | Reference | Comment |
---|---|---|---|
11.920 | 64.19 | Messerly and Finke, 1971 | DH |
11.92 | 164.2 | Domalski and Hearing, 1996 | AC |
Entropy of fusion
ΔfusS (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
72.60 | 64.19 | Messerly and Finke, 1971 | DH |
Gas phase ion energetics data
Go To: Top, Condensed phase thermochemistry data, Phase change data, Mass spectrum (electron ionization), 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:
L - Sharon G. Lias
Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 9.84 ± 0.10 | eV | N/A | N/A | L |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
9.76 | EST | Luo and Pacey, 1992 | LL |
9.84 ± 0.10 | EVAL | Lias, 1982 | LBLHLM |
9.74 ± 0.15 | EQ | Mautner(Meot-Ner), Sieck, et al., 1981 | LLK |
Mass spectrum (electron ionization)
Go To: Top, Condensed phase thermochemistry data, Phase change 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 by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.
Additional Data
View image of digitized spectrum (can be printed in landscape orientation).
Due to licensing restrictions, this spectrum cannot be downloaded.
Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
Origin | Japan AIST/NIMC Database- Spectrum MS-NW-4071 |
NIST MS number | 230535 |
References
Go To: Top, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, Mass spectrum (electron ionization), 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]
Fajans, 1920
Fajans, K.,
Die Energie der Atombindungen im Diamanten und in aliphatischen Kohlenwasserstoffen,
Ber., 1920, 53, 643-665. [all data]
Richards and Jesse, 1910
Richards, T.W.; Jesse, R.H., Jr.,
The heats of combustion of the octanes and xylenes,
J. Am. Chem. Soc., 1910, 32, 268-298. [all data]
Messerly and Finke, 1971
Messerly, J.F.; Finke, H.L.,
Low-temperature thermal properties of 2-methylheptane and 2-methyldecane: the thermodynamic properties of the 2-methylalkanes,
J. Chem. Thermodynam., 1971, 3, 675-687. [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]
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]
Abara, Jennings, et al., 1988
Abara, J.A.; Jennings, D.W.; Kay, W.B.; Teja, A.S.,
Phase Behavior in the Critical Region of Six Binary Mixtures of 2-Methylalkanes,
J. Chem. Eng. Data, 1988, 33, 242. [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]
McMicking and Kay, 1965
McMicking, J.H.; Kay, W.B.,
Vapor Pressures and Saturated Liquid and Vapor Densities of The Isomeric Heptanes and Isomeric Octanes,
Proc., Am. Pet. Inst., Sect. 3, 1965, 45, 75-90. [all data]
Ambrose, Cox, et al., 1960
Ambrose, D.; Cox, J.D.; Townsend, R.,
The critical temperatures of forty organic compounds,
Trans. Faraday Soc., 1960, 56, 1452. [all data]
Aldrich Chemical Company Inc., 1990
Aldrich Chemical Company Inc.,
Catalog Handbook of Fine Chemicals, Aldrich Chemical Company, Inc., Milwaukee WI, 1990, 1. [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]
Osborn and Douslin, 1974
Osborn, Ann G.; Douslin, Donald R.,
Vapor-pressure relations for 15 hydrocarbons,
J. Chem. Eng. Data, 1974, 19, 2, 114-117, https://doi.org/10.1021/je60061a022
. [all data]
Majer, Svoboda, et al., 1979
Majer, Vladimír; Svoboda, Václav; Hála, Slavoj; Pick, Jirí,
Temperature dependence of heats of vaporization of saturated hydrocarbons C5-C8; Experimental data and an estimation method,
Collect. Czech. Chem. Commun., 1979, 44, 3, 637-651, https://doi.org/10.1135/cccc19790637
. [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]
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, 1982
Lias, S.G.,
Thermochemical information from ion-molecule rate constants,
Ion Cyclotron Reson. Spectrom. 1982, 1982, 409. [all data]
Mautner(Meot-Ner), Sieck, et al., 1981
Mautner(Meot-Ner), M.; Sieck, L.W.; Ausloos, P.,
Ionization of normal alkanes: Enthalpy, entropy, structural, and isotope effects,
J. Am. Chem. Soc., 1981, 103, 5342. [all data]
Notes
Go To: Top, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, Mass spectrum (electron ionization), References
- Symbols used in this document:
Cp,liquid Constant pressure heat capacity of liquid IE (evaluated) Recommended ionization energy 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 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 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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