Octane

• Formula: C₈H₁₈
• Molecular weight: 114.2285
• IUPAC Standard InChI: InChI=1S/C8H18/c1-3-5-7-8-6-4-2/h3-8H2,1-2H3 Copy

  
• IUPAC Standard InChIKey: TVMXDCGIABBOFY-UHFFFAOYSA-N Copy
• CAS Registry Number: 111-65-9
• 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:
  • Octane-d18-
  • Octane-1,2,3,4,5,6-d13
  • Octane-1,2,3,4-d9
  • Octane-1,2-d5
• Other names: n-Octane; n-C8H18; Oktan; Oktanen; Ottani; UN 1262
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Phase change data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data
  • Henry's Law data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • Fluid Properties
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
  • Reference simulation
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Phase change data

Go To: Top, 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:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
BS - Robert L. Brown and Stephen E. Stein
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

Enthalpy of vaporization

Enthalpy of vaporization

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

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Antoine Equation Parameters

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

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Enthalpy of sublimation

Enthalpy of fusion

Entropy of fusion

Gas phase ion energetics data

Go To: Top, Phase change data, 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
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Ionization energy determinations

Appearance energy determinations

References

Go To: Top, Phase change 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.

Ambrose and Tsonopoulos, 1995
Ambrose, D.; Tsonopoulos, C., Vapor-Liquid Critical Properties of Elements and Compounds. 2. Normal Alkenes, J. Chem. Eng. Data, 1995, 40, 531-546. [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]

Ewing and Ochoa, 2003
Ewing, M.B.; Ochoa, J.C. Sanchez, The vapour pressures of n-octane determined using comparative ebulliometry, Fluid Phase Equilibria, 2003, 210, 2, 277-285, https://doi.org/10.1016/S0378-3812(03)00174-2 . [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]

Paul, Krug, et al., 1986
Paul, Hanns-Ingolf; Krug, Joseph; Knapp, Helmut, Measurements of VLE, hE and vE for binary mixtures of n-alkanes with n-alkylbenzenes, Thermochimica Acta, 1986, 108, 9-27, https://doi.org/10.1016/0040-6031(86)85073-0 . [all data]

Michou-Saucet, Jose, et al., 1984
Michou-Saucet, Marie-Annie; Jose, Jacques; Michou-Saucet, Christian; Merlin, J.C., Pressions de vapeur et enthalpies libres d'exces de systemes binaires: Hexamethylphosphorotriamide (HMPT) + n-hexane; n-heptane; n-octane: A 298,15 K; 303,15 K; 313,15 K; 323,15 K; 333,15 K, Thermochimica Acta, 1984, 75, 1-2, 85-106, https://doi.org/10.1016/0040-6031(84)85009-1 . [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]

Carruth and Kobayashi, 1973
Carruth, Grant F.; Kobayashi, Riki, Vapor pressure of normal paraffins ethane through n-decane from their triple points to about 10 mm mercury, J. Chem. Eng. Data, 1973, 18, 2, 115-126, https://doi.org/10.1021/je60057a009 . [all data]

McKay and Sage, 1960
McKay, R.A.; Sage, B.H., Latent Heat of Vaporization for n-Octane., J. Chem. Eng. Data, 1960, 5, 1, 21-24, https://doi.org/10.1021/je60005a005 . [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]

Bondi, 1963
Bondi, A., Heat of Siblimation of Molecular Crystals: A Catalog of Molecular Structure Increments., J. Chem. Eng. Data, 1963, 8, 3, 371-381, https://doi.org/10.1021/je60018a027 . [all data]

Finke, Gross, et al., 1954
Finke, H.L.; Gross, M.E.; Waddington, G.; Huffman, H.M., Low-temperature thermal data for the nine normal paraffin hydrocarbons from octane to hexadecane, J. Am. Chem. Soc., 1954, 76, 333-341. [all data]

Mondieig, Rajabalee, et al., 2004
Mondieig, D.; Rajabalee, F.; Metivaud, V.; Oonk, H.A.J.; Cuevas-Diarte, M.A., n -Alkane Binary Molecular Alloys, Chem. Mater., 2004, 16, 5, 786-798, https://doi.org/10.1021/cm031169p . [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]

Huffman, Parks, et al., 1931
Huffman, H.M.; Parks, G.S.; Barmore, M., Thermal data on organic compounds. X. Further studies on the heat capacities, entropies and free energies of hydrocarbons, J. Am. Chem. Soc., 1931, 53, 3876-3888. [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]

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]

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]

Potzinger and Bunau, 1969
Potzinger, P.; Bunau, G.v., Empirische Beruksichtigung von Uberschussenergien bei der Auftrittspotentialbestimmung, Ber. Bunsen-Ges. Phys. Chem., 1969, 73, 466. [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]

Lewis and Hamill, 1970
Lewis, D.; Hamill, W.H., Excited states of neutral molecular fragments from appearance potentials by electron impact in a mass spectrometer, J. Chem. Phys., 1970, 52, 6348. [all data]

Notes

Go To: Top, Phase change data, Gas phase ion energetics data, References

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  Pc	Critical pressure
  Tboil	Boiling point
  Tc	Critical temperature
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  Vc	Critical volume
  ΔfusH	Enthalpy of fusion
  ΔfusS	Entropy of fusion
  ΔsubH	Enthalpy of sublimation
  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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