Pentane, 2,2,4-trimethyl-
- Formula: C8H18
- Molecular weight: 114.2285
- IUPAC Standard InChIKey: NHTMVDHEPJAVLT-UHFFFAOYSA-N
- 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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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
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Tboil | 372.4 ± 0.2 | K | AVG | N/A | Average of 49 out of 52 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 165.77 ± 0.06 | K | AVG | N/A | Average of 37 out of 44 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 165.760 | K | N/A | Streiff, 1959 | Uncertainty assigned by TRC = 0.4 K; TRC |
Ttriple | 165.3 | K | N/A | Parks, Huffman, et al., 1930 | Uncertainty assigned by TRC = 0.2 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 543.9 ± 0.4 | K | AVG | N/A | Average of 6 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 25.4 ± 0.2 | atm | N/A | Daubert, 1996 | |
Pc | 25.340 | atm | N/A | McMicking and Kay, 1965 | Uncertainty assigned by TRC = 0.4000 atm; TRC |
Pc | 25.3080 | atm | N/A | Kay and Warzel, 1951 | Uncertainty assigned by TRC = 0.09998 atm; TRC |
Pc | 25.5000 | atm | N/A | Beattie and Edwards, 1948 | Uncertainty assigned by TRC = 0.1499 atm; from observed isotherms in critical region; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Vc | 0.468 | l/mol | N/A | Daubert, 1996 | |
Vc | 0.482 | l/mol | N/A | Beattie and Edwards, 1948 | Uncertainty assigned by TRC = 0.02 l/mol; from observed isotherms in the critical region; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 2.14 ± 0.02 | mol/l | N/A | Daubert, 1996 | |
ρc | 2.13 | mol/l | N/A | McMicking and Kay, 1965 | Uncertainty assigned by TRC = 0.04 mol/l; TRC |
ρc | 2.13 | mol/l | N/A | Kay and Warzel, 1951 | Uncertainty assigned by TRC = 0.03 mol/l; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ΔvapH° | 8.39 ± 0.05 | kcal/mol | AVG | N/A | Average of 7 values; Individual data points |
Enthalpy of vaporization
ΔvapH (kcal/mol) | Temperature (K) | Method | Reference | Comment |
---|---|---|---|---|
7.359 | 372.4 | N/A | Majer and Svoboda, 1985 | |
8.63 | 304. | N/A | Wu, Pividal, et al., 1991 | Based on data from 289. to 333. K.; AC |
7.55 | 438. | A | Stephenson and Malanowski, 1987 | Based on data from 423. to 523. K.; AC |
7.70 | 387. | A | Stephenson and Malanowski, 1987 | Based on data from 372. to 416. K.; AC |
7.53 | 428. | A | Stephenson and Malanowski, 1987 | Based on data from 413. to 494. K.; AC |
7.50 | 505. | A | Stephenson and Malanowski, 1987 | Based on data from 490. to 544. K.; AC |
9.73 | 209. | A | Stephenson and Malanowski, 1987 | Based on data from 194. to 299. K. See also Milazzo, 1956.; AC |
8.32 | 312. | A,MM | Stephenson and Malanowski, 1987 | Based on data from 297. to 374. K. See also Willingham, Taylor, et al., 1945.; AC |
8.22 ± 0.02 | 313. | C | Svoboda, Charvátová, et al., 1982 | AC |
7.98 ± 0.02 | 328. | C | Svoboda, Charvátová, et al., 1982 | AC |
7.79 ± 0.02 | 343. | C | Svoboda, Charvátová, et al., 1982 | AC |
7.58 ± 0.02 | 358. | C | Svoboda, Charvátová, et al., 1982 | AC |
7.41 ± 0.02 | 368. | C | Svoboda, Charvátová, et al., 1982 | AC |
8.20 ± 0.02 | 313. | C | Majer, Svoboda, et al., 1979 | AC |
7.93 ± 0.02 | 333. | C | Majer, Svoboda, et al., 1979 | AC |
7.65 ± 0.02 | 353. | C | Majer, Svoboda, et al., 1979 | AC |
7.41 | 371. | C | Pitzer K.S., 1940 | AC |
8.10 | 333. | EB | Smith, 1940 | Based on data from 318. to 399. K.; AC |
Enthalpy of vaporization
ΔvapH =
A exp(-βTr) (1 − Tr)β
ΔvapH =
Enthalpy of vaporization (at saturation pressure)
(kcal/mol)
Tr = reduced temperature (T / Tc)
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Temperature (K) | A (kcal/mol) | β | Tc (K) | Reference | Comment |
---|---|---|---|---|---|
298. to 353. | 12.02 | 0.2668 | 543.9 | Majer and Svoboda, 1985 |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (atm)
T = temperature (K)
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Temperature (K) | A | B | C | Reference | Comment |
---|---|---|---|---|---|
194.64 to 298.44 | 3.94165 | 1282.332 | -48.444 | Milazzo, 1956, 2 | Coefficents calculated by NIST from author's data. |
297.51 to 373.28 | 3.93108 | 1257.84 | -52.415 | Williamham, Taylor, et al., 1945 |
Enthalpy of fusion
ΔfusH (kcal/mol) | Temperature (K) | Reference | Comment |
---|---|---|---|
2.2016 | 165.79 | Pitzer K.S., 1940 | DH |
2.16 | 165.3 | Domalski and Hearing, 1996 | AC |
2.161 | 165.3 | Parks, Huffman, et al., 1930, 2 | DH |
Entropy of fusion
ΔfusS (cal/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
13.28 | 165.79 | Pitzer K.S., 1940 | DH |
13.07 | 165.3 | Parks, Huffman, et al., 1930, 2 | DH |
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:
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 9.89 ± 0.03 | eV | N/A | N/A | L |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
9.91 | PE | Al-Joboury and Turner, 1964 | RDSH |
9.86 | PI | Watanabe, Nakayama, et al., 1962 | RDSH |
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.
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]
Al-Joboury and Turner, 1964
Al-Joboury, M.I.; Turner, D.W.,
Molecular photoelectron spectroscopy. Part II. A summary of ionization potentials,
J. Chem. Soc., 1964, 4434. [all data]
Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J.,
Ionization potentials of some molecules,
J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]
Notes
Go To: Top, Phase change data, Gas phase ion energetics data, References
- Symbols used in this document:
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 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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