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:
  • Gas phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Henry's Law data
  • Gas phase ion energetics data
  • Fluid Properties
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
  • Reference simulation
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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:
DRB - Donald R. Burgess, Jr.
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

Phase change data

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, IR Spectrum, 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:
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

Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Phase change data, IR Spectrum, 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 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: C₈H₁₆ + H₂ = C₈H₁₈

 +  =

By formula: H₂ + C₈H₁₆ = C₈H₁₈

2 +  =

By formula: 2H₂ + C₈H₁₄ = C₈H₁₈

2 +  =

By formula: 2H₂ + C₈H₁₄ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

=

By formula: C₈H₁₈ = C₈H₁₈

 +  =

By formula: H₂ + C₈H₁₆ = C₈H₁₈

 +  =

By formula: H₂ + C₈H₁₆ = C₈H₁₈

 +  =

By formula: H₂ + C₈H₁₆ = C₈H₁₈

 +  =

By formula: H₂ + C₈H₁₆ = C₈H₁₈

2 +  =

By formula: 2H₂ + C₈H₁₄ = C₈H₁₈

 +  =

By formula: H₂ + C₈H₁₆ = C₈H₁₈

2 +  =

By formula: 2H₂ + C₈H₁₄ = C₈H₁₈

4 +  =

By formula: 4H₂ + C₈H₁₀ = C₈H₁₈

3 +  =

By formula: 3H₂ + C₈H₁₂ = C₈H₁₈

4 +  =

By formula: 4H₂ + C₈H₁₀ = C₈H₁₈

=  + 

By formula: C₈H₁₈ = H₂ + C₈H₁₆

=  + 

By formula: C₈H₁₈ = H₂ + C₈H₁₆

=  + 

By formula: C₈H₁₈ = H₂ + C₈H₁₆

=  + 

By formula: C₈H₁₈ = H₂ + C₈H₁₆

=  + 

By formula: C₈H₁₈ = H₂ + C₈H₁₆

=  + 

By formula: C₈H₁₈ = H₂ + C₈H₁₆

=  + 

By formula: C₈H₁₈ = C₈H₁₆ + H₂

IR Spectrum

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), References, Notes

Data compiled by: Tanya L. Myers, Russell G. Tonkyn, Ashley M. Oeck, Tyler O. Danby, John S. Loring, Matthew S. Taubman, Stephen W. Sharpe, Jerome C. Birnbaum, and Timothy J. Johnson

• liquid; Bruker Tensor 27 FTIR; 0.48212986 cm^-1 resolution

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

• gas

Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, IR Spectrum, 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

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Additional Data

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, IR Spectrum, 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.

Good, 1972
Good, W.D., The enthalpies of combustion and formation of n-octane and 2,2,3,3-tetramethylbutane, J. Chem. Thermodyn., 1972, 4, 709-714. [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]

Prosen and Rossini, 1944
Prosen, E.J.; Rossini, F.D., Heats of combustion of eight normal paraffin hydrocarbons in the liquid state, J. Res. NBS, 1944, 33, 255-272. [all data]

Scott D.W., 1974
Scott D.W., Correlation of the chemical thermodynamic properties of alkane hydrocarbons, J. Chem. Phys., 1974, 60, 3144-3165. [all data]

Messerly J.F., 1967
Messerly J.F., Low-temperature thermal data for n-pentane, n-heptadecane, and n-octadecane. Revised thermodynamic functions for the n-alkanes, C5-C18, J. Chem. Eng. Data, 1967, 12, 338-346. [all data]

Hossenlopp I.A., 1981
Hossenlopp I.A., Vapor heat capacities and enthalpies of vaporization of five alkane hydrocarbons, J. Chem. Thermodyn., 1981, 13, 415-421. [all data]

Barrow G.M., 1951
Barrow G.M., Experimental vapor heat capacities and heats of vaporization of seven octanes, J. Am. Chem. Soc., 1951, 73, 1824-1826. [all data]

Scott D.W., 1974, 2
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]

Pitzer K.S., 1944
Pitzer K.S., Thermodynamics of gaseous paraffins. Specific heat and related properties, Ind. Eng. Chem., 1944, 36, 829-831. [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]

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]

Rogers, Dejroongruang, et al., 1992
Rogers, D.W.; Dejroongruang, K.; Samuel, S.D.; Fang, W.; Zhao, Y., Enthalpies of hydrogenation of the octenes and the methylheptenes, J. Chem. Thermodyn., 1992, 24, 561-565. [all data]

Rogers and Siddiqui, 1975
Rogers, D.W.; Siddiqui, N.A., Heats of hydrogenation of large molecules. I. Esters of unsaturated fatty acids, J. Phys. Chem., 1975, 79, 574-577. [all data]

Turner, Jarrett, et al., 1973
Turner, R.B.; Jarrett, A.D.; Goebel, P.; Mallon, B.J., Heats of hydrogenation. 9. Cyclic acetylenes and some miscellaneous olefins, J. Am. Chem. Soc., 1973, 95, 790-792. [all data]

Rogers, Dagdagan, et al., 1979
Rogers, D.W.; Dagdagan, O.A.; Allinger, N.L., Heats of hydrogenation and formation of linear alkynes and a molecular mechanics interpretation, J. Am. Chem. Soc., 1979, 101, 671-676. [all data]

Sicher, Svoboda, et al., 1966
Sicher, J.; Svoboda, M.; Zavada, J.; Turner, R.B.; Goebel, P., Sterochemical studies - XXXVI. An approach to conformational analysis of medium ring compounds. Unsaturated ten-membered ring derivates, Tetrahedron, 1966, 22, 659-671. [all data]

Molnar, Rachford, et al., 1984
Molnar, A.; Rachford, R.; Smith, G.V.; Liu, R., Heats of hydrogenation by a simple and rapid flow calorimetric method, Appl. Catal., 1984, 9, 219-223. [all data]

Prosen and Rossini, 1945, 2
Prosen, E.J.; Rossini, F.D., Heats of isomerization of the 18 octanes, J. Res. NBS, 1945, 34, 163-174. [all data]

Flitcroft, Skinner, et al., 1957
Flitcroft, T.; Skinner, H.A.; Whiting, M.C., Heats of hydrogenation Part 1.-Dodeca-3:9 and -5:7 Diynes, Trans. Faraday Soc., 1957, 53, 784-790. [all data]

Flitcroft and Skinner, 1958
Flitcroft, T.L.; Skinner, H.A., Heats of hydrogenation Part 2.-Acetylene derivatives, Trans. Faraday Soc., 1958, 54, 47-53. [all data]

Roth, Scholz, et al., 1982
Roth, W.R.; Scholz, B.P.; Breuckmann, R.; Jelich, K.; Lennartz, H.W., Thermolysis of 1,2,6,7-octatetraene, Chem. Ber., 1982, 115, 1934-1946. [all data]

Eliseev, 1986
Eliseev, N.A., Thermodynamic calculation of the equilibrium composition of isomeric octenes in dehydrogenation of n-octane, Izv. Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol., 1986, 29, 26-29. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), References

• Symbols used in this document:
  

  Cp,gas	Constant pressure heat capacity of gas
  Pc	Critical pressure
  S°gas	Entropy of gas at standard conditions
  Tboil	Boiling point
  Tc	Critical temperature
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  Vc	Critical volume
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfusH	Enthalpy of fusion
  ΔfusS	Entropy of fusion
  ΔrH°	Enthalpy of reaction at standard conditions
  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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