Pentane, 2,2,4-trimethyl-

• Formula: C₈H₁₈
• Molecular weight: 114.2285
• IUPAC Standard InChI: InChI=1S/C8H18/c1-7(2)6-8(3,4)5/h7H,6H2,1-5H3 Copy

  
• IUPAC Standard InChIKey: NHTMVDHEPJAVLT-UHFFFAOYSA-N Copy
• CAS Registry Number: 540-84-1
• 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: Isooctane; Isobutyltrimethylmethane; 2,2,4-Trimethylpentane; (CH3)2CHCH2C(CH3)3; Isobutyltrimethylethane; UN 1262
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• Information on this page:
  • Phase change data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data
  • Henry's Law data
  • Gas phase ion energetics data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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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:
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(-βT_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 fusion

Entropy of fusion

References

Go To: Top, Phase change data, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Streiff, 1959
Streiff, A.J., Unpublished 1959, 1959. [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, 1032-41. [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]

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]

Kay and Warzel, 1951
Kay, W.B.; Warzel, F.M., 2,2,4-Trimethylpentane (Isooctane), Vapor Pressure, Critical Constants and Saturated Vapor and Liquid Densities, Ind. Eng. Chem., 1951, 43, 1150-2. [all data]

Beattie and Edwards, 1948
Beattie, J.A.; Edwards, D.G., The Vapor Pressure, Orthobaric Densities, and Critical Constants of 2,2,4-Trimethylpentane, J. Am. Chem. Soc., 1948, 70, 3382. [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]

Wu, Pividal, et al., 1991
Wu, Huey S.; Pividal, Katherine A.; Sandler, Stanley I., Vapor-liquid equilibria of hydrocarbons and fuel oxygenates, J. Chem. Eng. Data, 1991, 36, 4, 418-421, https://doi.org/10.1021/je00004a021 . [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]

Milazzo, 1956
Milazzo, G., Ann. Chim. (Rome), 1956, 46, 1105. [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]

Svoboda, Charvátová, et al., 1982
Svoboda, Václav; Charvátová, Vladimíra; Majer, Vladimír; Hynek, Vladimír, Determination of heats of vaporization and some other thermodynamic properties for four substituted hydrocarbons, Collect. Czech. Chem. Commun., 1982, 47, 2, 543-549, https://doi.org/10.1135/cccc19820543 . [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]

Pitzer K.S., 1940
Pitzer K.S., The thermodynamics of n-heptane and 2,2,4-trimethylpentane, including heat capacities, heats of fusion and vaporization and entropies, J. Am. Chem. Soc., 1940, 62, 1224-1227. [all data]

Smith, 1940
Smith, E.R., Boiling points of n-heptane and 2,2,4-trimethylpentane over the range 100- to 1,500-millimeter pressure, J. RES. NATL. BUR. STAN., 1940, 24, 3, 229-17, https://doi.org/10.6028/jres.024.010 . [all data]

Milazzo, 1956, 2
Milazzo, G., Tensioni di Vapore di Alcune Sostanze Organiche a Bassa Temperatura, Ann. Chim. (Rome), 1956, 46, 1105-1111. [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]

Parks, Huffman, et al., 1930, 2
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]

Notes

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• Symbols used in this document:
  

  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
  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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