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:
  • Condensed phase thermochemistry data
  • Phase change data
  • IR Spectrum
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • Henry's Law data
  • Gas phase ion energetics data
  • Mass spectrum (electron ionization)
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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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

Go To: Top, Condensed phase 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 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) (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

IR Spectrum

Go To: Top, Condensed phase thermochemistry data, Phase change data, References, Notes

Data compiled by: Coblentz Society, Inc.

• GAS (16 mmHg DILUTED TO A TOTAL PRESSURE OF 600 mmHg WITH N2); DIGILAB FTS-14 (2 CM^-1 RESOLUTION); DIGITIZED BY NIST FROM HARD COPY (FROM TWO SEGMENTS); 4 cm^-1 resolution
• GAS (16 mmHg, N2 ADD, TOTAL PRESSURE 600 mmHg); DIGILAB FTS-14 (2 CM^-1 RESOLUTION); DIGITIZED BY NIST FROM HARD COPY (FROM TWO SEGMENTS); 2 cm^-1 resolution
• SOLUTION (10% IN CCl4 FOR 3800-1330 CM^-1, 10% IN CS2 FOR 1330-400 CM^-1); DOW KBr FOREPRISM-GRATING; DIGITIZED BY NIST FROM HARD COPY (FROM TWO SEGMENTS); 4 cm^-1 resolution

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

• gas

References

Go To: Top, Condensed phase thermochemistry data, Phase change data, IR Spectrum, 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]

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]

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]

Costas, Huu, et al., 1988
Costas, M.; Huu, V.T.; Patterson, D.; Caceres-Alonso, M.; Tardajos, G.; Aicart, E., Liquid structure and second-order mixing functions for l-chloronaphthalene with linear and branched alkanes, J. Chem. Soc., Faraday Trans., 1988, 1 84(5), 1603-1616. [all data]

Perez-Casas, Aicart, et al., 1988
Perez-Casas, S.; Aicart, E.; Trojo, L.M.; Costas, M., Excess heat capacity. Chlorobenzene-2,2,4,4,6,8,8-heptamethylnonane, Int. Data Ser., Sel. Data Mixtures, 1988, (2)A, 123. [all data]

Shiohama, Ogawa, et al., 1988
Shiohama, Y.; Ogawa, H.; Murakami, S.; Fujihara, I., Excess molar isobaric heat capacities and isentropic compressibilities of (cis- or trans-decalin + benzene or toluene or iso-octane or n-heptane) at 298.15 K, J. Chem. Thermodynam., 1988, 20, 1183-1189. [all data]

Kalali, Kohler, et al., 1987
Kalali, H.; Kohler, F.; Svejda, P., Excess properties of the mixture bis(2-dichlorethyl)ether (chlorex) + 2,2,4-trimethylpentane (isooctane), Monatsh. Chem., 1987, 118, 1-18. [all data]

Fortier and Benson, 1976
Fortier, J.-L.; Benson, G.C., Excess heat capacities of binary liquid mixtures determined with a Picker flow calorimeter, J. Chem. Thermodynam., 1976, 8, 411-423. [all data]

Rajagopal and Subrahmanyam, 1974
Rajagopal, E.; Subrahmanyam, S.V., Excess function of VE,(dVE/dp)T, and CpE of isooctane + benzene and + toluene, J. Chem. Thermodynam., 1974, 6, 873-876. [all data]

Subrahmanyam and Rajagopal, 1973
Subrahmanyam, S.V.; Rajagopal, E., Excess thermodynamic functions of the systems isooctane + carbon tetrachloride and isooctane + cyclohexane, Z. Phys. Chem. [NF], 1973, 85, 256-268. [all data]

Auerbach, Sage, et al., 1950
Auerbach, C.E.; Sage, B.H.; Lacey, W.N., Isobaric heat capacities at bubble point, Ind. Eng. Chem., 1950, 42, 110-113. [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]

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

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]

Notes

Go To: Top, Condensed phase thermochemistry data, Phase change data, IR Spectrum, References

• Symbols used in this document:
  

  Cp,liquid	Constant pressure heat capacity of liquid
  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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