Hexane, 3-methyl-

Formula: C₇H₁₆
Molecular weight: 100.2019
IUPAC Standard InChI: InChI=1S/C7H16/c1-4-6-7(3)5-2/h7H,4-6H2,1-3H3
IUPAC Standard InChIKey: VLJXXKKOSFGPHI-UHFFFAOYSA-N
CAS Registry Number: 589-34-4
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Stereoisomers:
- (S)-(+)-3-methylhexane
Other names: 2-Ethylpentane; 3-Methylhexane
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Gas phase thermochemistry data

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Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-45.96 ± 0.30	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Δ_fH°_gas	-46.10	kcal/mol	N/A	Davies and Gilbert, 1941	Value computed using Δ_fH_liquid° value of -228.0±1.0 kj/mol from Davies and Gilbert, 1941 and Δ_vapH° value of 35.1 kj/mol from Prosen and Rossini, 1945.; DRB

Condensed phase thermochemistry data

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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

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_liquid	-54.35 ± 0.30	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Δ_fH°_liquid	-54.4 ± 0.3	kcal/mol	Ccb	Davies and Gilbert, 1941	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-1150.55 ± 0.28	kcal/mol	Ccb	Prosen and Rossini, 1945	Corresponding Δ_fHº_liquid = -54.33 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-1150.3 ± 0.3	kcal/mol	Ccb	Davies and Gilbert, 1941	Corresponding Δ_fHº_liquid = -54.63 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	74.00	cal/mol*K	N/A	Huffman, Parks, et al., 1930	Extrapolation below 70 K, 70.71 J/molK. Forms glass at low temperatures. Value includes estimated zero point entropy of 17 J/molK.; DH

Constant pressure heat capacity of liquid

C_p,liquid (cal/mol*K)	Temperature (K)	Reference	Comment
51.79	289.2	Parks, Thomas, et al., 1936	T = 71 to 290 K. Glass at lower temperatures. Value is unsmoothed experimental datum.; DH
51.20	289.2	Huffman, Parks, et al., 1930	T = 71 to 289 K. Value is unsmoothed experimental datum.; DH

Phase change data

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Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos

Quantity	Value	Units	Method	Reference	Comment
T_boil	365.0 ± 0.3	K	AVG	N/A	Average of 34 out of 38 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_fus	153.75	K	N/A	Timmermans, 1921	Uncertainty assigned by TRC = 0.5 K; TRC
Quantity	Value	Units	Method	Reference	Comment
T_c	535.2 ± 0.4	K	N/A	Daubert, 1996
T_c	535.2	K	N/A	Majer and Svoboda, 1985
T_c	535.19	K	N/A	McMicking and Kay, 1965	Uncertainty assigned by TRC = 0.4 K; TRC
T_c	535.55	K	N/A	Edgar and Calingaert, 1929	Uncertainty assigned by TRC = 0.5 K; measured by Keys and Kleinschmidt; TRC
Quantity	Value	Units	Method	Reference	Comment
P_c	27.7 ± 0.4	atm	N/A	Daubert, 1996
P_c	27.767	atm	N/A	McMicking and Kay, 1965	Uncertainty assigned by TRC = 0.4000 atm; TRC
P_c	28.13	atm	N/A	Edgar and Calingaert, 1929	Uncertainty assigned by TRC = 50.663 atm; measured by Keys and Kleinschmidt; TRC
Quantity	Value	Units	Method	Reference	Comment
V_c	0.404	l/mol	N/A	Daubert, 1996
Quantity	Value	Units	Method	Reference	Comment
ρ_c	2.47 ± 0.04	mol/l	N/A	Daubert, 1996
ρ_c	2.48	mol/l	N/A	McMicking and Kay, 1965	Uncertainty assigned by TRC = 0.05 mol/l; TRC
Quantity	Value	Units	Method	Reference	Comment
Δ_vapH°	8.403	kcal/mol	N/A	Majer and Svoboda, 1985
Δ_vapH°	8.39 ± 0.02	kcal/mol	C	Majer, Svoboda, et al., 1979	AC
Δ_vapH°	8.39	kcal/mol	N/A	Reid, 1972	AC

Enthalpy of vaporization

Δ_vapH (kcal/mol)	Temperature (K)	Method	Reference	Comment
7.383	365.	N/A	Majer and Svoboda, 1985
8.39	304.	A	Stephenson and Malanowski, 1987	Based on data from 289. to 366. K.; AC
8.17 ± 0.02	313.	C	Majer, Svoboda, et al., 1979	AC
7.86 ± 0.02	333.	C	Majer, Svoboda, et al., 1979	AC
7.58 ± 0.02	353.	C	Majer, Svoboda, et al., 1979	AC
8.34	308.	N/A	Forziati, Norris, et al., 1949	Based on data from 293. to 366. K.; AC

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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Temperature (K)	A (kcal/mol)	β	T_c (K)	Reference	Comment
298. to 353.	12.3	0.2776	535.2	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
293.06 to 365.89	3.99314	1243.759	-53.524	Forziati, Norris, et al., 1949, 2	Coefficents calculated by NIST from author's data.

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:

Reaction thermochemistry data

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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

+ = Hexane, 3-methyl-

By formula: C₇H₁₄ + H₂ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-25.7 ± 0.1	kcal/mol	Chyd	Rogers and Dejroongruang, 1988	liquid phase; solvent: Hydrocarbone

+ = Hexane, 3-methyl-

By formula: H₂ + C₇H₁₄ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-27.39 ± 0.26	kcal/mol	Chyd	Rogers and Dejroongruang, 1989	liquid phase; solvent: Cyclohexane

+ = Hexane, 3-methyl-

By formula: H₂ + C₇H₁₄ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-29.76 ± 0.1	kcal/mol	Chyd	Rogers and Dejroongruang, 1988	liquid phase; solvent: Hydrocarbone

+ = Hexane, 3-methyl-

By formula: H₂ + C₇H₁₄ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-29.33 ± 0.07	kcal/mol	Chyd	Rogers and Dejroongruang, 1988	liquid phase; solvent: Hydrocarbone

+ = Hexane, 3-methyl-

By formula: H₂ + C₇H₁₄ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-27.63 ± 0.07	kcal/mol	Chyd	Rogers and Dejroongruang, 1988	liquid phase; solvent: Hydrocarbone

+ = Hexane, 3-methyl-

By formula: H₂ + C₇H₁₄ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-26.58 ± 0.1	kcal/mol	Chyd	Rogers and Dejroongruang, 1988	liquid phase; solvent: Hydrocarbone

+ = Hexane, 3-methyl-

By formula: H₂ + C₇H₁₄ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-26.43 ± 0.1	kcal/mol	Chyd	Rogers and Dejroongruang, 1988	liquid phase; solvent: Hydrocarbone

+ = Hexane, 3-methyl-

By formula: H₂ + C₇H₁₄ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-26.15 ± 0.1	kcal/mol	Chyd	Rogers and Dejroongruang, 1988	liquid phase; solvent: Hydrocarbone

= Hexane, 3-methyl-

By formula: C₇H₁₆ = C₇H₁₆

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-0.024 ± 0.050	kcal/mol	Eqk	Roganov, Kabo, et al., 1972	gas phase; At 368 K

References

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

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]

Davies and Gilbert, 1941
Davies, G.F.; Gilbert, E.C., Heats of combustion and formation of the nine isomeric heptanes in the liquid state, J. Am. Chem. Soc., 1941, 63, 2730-2732. [all data]

Huffman, Parks, et al., 1930
Huffman, H.M.; Parks, G.S.; Thomas, S.B., Thermal data on organic compounds. VIII. The heat capacities, entropies and free energies of the isomeric heptanes, J. Am. Chem. Soc., 1930, 52, 3241-3251. [all data]

Parks, Thomas, et al., 1936
Parks, G.S.; Thomas, S.B.; Light, D.W., XII. Some new heat capacity data for organic glasses. The entropy and free energy of DL-lactic acid, J. Chem. Phys., 1936, 4, 64-69. [all data]

Timmermans, 1921
Timmermans, J., The Freezing Points of Organic Substances IV. New Exp. Determinations, Bull. Soc. Chim. Belg., 1921, 30, 62. [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]

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]

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]

Edgar and Calingaert, 1929
Edgar, G.; Calingaert, G., Preparation and Properties of the Isomeric Heptanes II. Physical Prop. properties, J. Am. Chem. Soc., 1929, 51, 1540. [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]

Reid, 1972
Reid, Robert C., Handbook on vapor pressure and heats of vaporization of hydrocarbons and related compounds, R. C. Wilhort and B. J. Zwolinski, Texas A Research Foundation. College Station, Texas(1971). 329 pages.$10.00, AIChE J., 1972, 18, 6, 1278-1278, https://doi.org/10.1002/aic.690180637 . [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]

Forziati, Norris, et al., 1949
Forziati, Alphonse F.; Norris, William R.; Rossini, Frederick D., Vapor pressures and boiling points of sixty API-NBS hydrocarbons, J. RES. NATL. BUR. STAN., 1949, 43, 6, 555-17, https://doi.org/10.6028/jres.043.050 . [all data]

Forziati, Norris, et al., 1949, 2
Forziati, A.F.; Norris, W.R.; Rossini, F.D., Vapor Pressures and Boiling Points of Sixty API-NBS Hydrocarbons, J. Res. Natl. Bur. Stand. (U.S.), 1949, 43, 6, 555-563, https://doi.org/10.6028/jres.043.050 . [all data]

Rogers and Dejroongruang, 1988
Rogers, D.W.; Dejroongruang, K., Enthalpies of hydrogenation of the n-heptenes and the methylhexenes, J. Chem. Thermodyn., 1988, 20, 675-680. [all data]

Rogers and Dejroongruang, 1989
Rogers, D.W.; Dejroongruang, K., Enthalpies of hydrogenation of the dimethylpentenes, ethylpentenes, methylbutene, and trimethylbutene, J. Chem. Thermodyn., 1989, 21, 1115-1120. [all data]

Roganov, Kabo, et al., 1972
Roganov, G.N.; Kabo, G.Ya.; Andreevskii, D.N., Thermodynamics of the isomerization of methylpentanes and methylheptanes, Neftekhimiya, 1972, 12, 495-500. [all data]

Notes

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Symbols used in this document:

C_p,liquid	Constant pressure heat capacity of liquid
P_c	Critical pressure
S°_liquid	Entropy of liquid at standard conditions
T_boil	Boiling point
T_c	Critical temperature
T_fus	Fusion (melting) point
V_c	Critical volume
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions
Δ_vapH	Enthalpy of vaporization
Δ_vapH°	Enthalpy of vaporization at standard conditions
ρ_c	Critical density

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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