Heptane, 2-methyl-

• Formula: C₈H₁₈
• Molecular weight: 114.2285
• IUPAC Standard InChI: InChI=1S/C8H18/c1-4-5-6-7-8(2)3/h8H,4-7H2,1-3H3 Copy

  
• IUPAC Standard InChIKey: JVSWJIKNEAIKJW-UHFFFAOYSA-N Copy
• 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:
  • 2-Methylheptane-d18
• Other names: 2-Methylheptane; (CH3)2CH(CH2)4CH3; Methylheptane
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• Information on this page:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Henry's Law data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Reaction thermochemistry data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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Gas phase 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 as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Constant pressure heat capacity of gas

Constant pressure heat capacity of gas

Condensed phase 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 as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of liquid

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
DH - Eugene S. Domalski and Elizabeth D. Hearing

Reduced pressure boiling point

Enthalpy of vaporization

Enthalpy of vaporization

Δ_vapH = A exp(-βT_r) (1 − T_r)^β
    Δ_vapH = Enthalpy of vaporization (at saturation pressure) (kcal/mol)
    T_r = reduced temperature (T / T_c)

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Antoine Equation Parameters

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

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Enthalpy of fusion

Entropy of fusion

Henry's Law 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: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

Gas phase ion energetics 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 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

Ionization energy determinations

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Henry's Law 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]

Messerly J.F., 1971
Messerly J.F., Low-temperature thermal properties of 2-methylheptane and 2-methyldecane: the thermodynamic properties of 2-methylalkanes, J. Chem. Thermodyn., 1971, 3, 675-687. [all data]

Colgate S.O., 1990
Colgate S.O., Acoustical determination of ideal gas heat capacities of three C-8 compounds, Fluid Phase Equilib., 1990, 60, 191-203. [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]

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, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Henry's Law data, Gas phase ion energetics data, References

• Symbols used in this document:
  

  Cp,gas	Constant pressure heat capacity of gas
  Cp,liquid	Constant pressure heat capacity of liquid
  IE (evaluated)	Recommended ionization energy
  Pc	Critical pressure
  S°gas	Entropy of gas at standard conditions
  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
  d(ln(kH))/d(1/T)	Temperature dependence parameter for Henry's Law constant
  k°H	Henry's Law constant at 298.15K
  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
  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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