Pentane, 2,4-dimethyl-

Formula: C₇H₁₆
Molecular weight: 100.2019
IUPAC Standard InChI: InChI=1S/C7H16/c1-6(2)5-7(3)4/h6-7H,5H2,1-4H3
IUPAC Standard InChIKey: BZHMBWZPUJHVEE-UHFFFAOYSA-N
CAS Registry Number: 108-08-7
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: 2,4-Dimethylpentane
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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.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-48.30 ± 0.23	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Δ_fH°_gas	-49.02	kcal/mol	N/A	Davies and Gilbert, 1941	Value computed using Δ_fH_liquid° value of -238.0±1.0 kj/mol from Davies and Gilbert, 1941 and Δ_vapH° value of 32.9 kj/mol from Prosen and Rossini, 1945.; DRB
Quantity	Value	Units	Method	Reference	Comment
S°_gas	94.821	cal/mol*K	N/A	Huffman H.M., 1961	GT

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
27.591	200.	Scott D.W., 1974	Recommended values were obtained from the consistent correlation scheme for alkanes [ Scott D.W., 1974, 2, Scott D.W., 1974]. This approach gives a good agreement with experimental data available for alkanes. However, large uncertainties could be expected at high temperatures.; GT
37.660	273.15
40.81 ± 0.1	298.15
41.040	300.
52.600	400.
62.469	500.
70.801	600.
78.000	700.
84.199	800.
89.500	900.
94.199	1000.
98.301	1100.
101.90	1200.
105.00	1300.
108.00	1400.
111.00	1500.

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	-56.17 ± 0.23	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Δ_fH°_liquid	-57.0 ± 0.3	kcal/mol	Ccb	Davies and Gilbert, 1941	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-1148.73 ± 0.20	kcal/mol	Ccb	Prosen and Rossini, 1945	Corresponding Δ_fHº_liquid = -56.15 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-1147.8 ± 0.3	kcal/mol	Ccb	Davies and Gilbert, 1941	Corresponding Δ_fHº_liquid = -57.10 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	72.459	cal/mol*K	N/A	Huffman, Gross, et al., 1961	DH
S°_liquid	69.69	cal/mol*K	N/A	Huffman, Parks, et al., 1930	Extrapolation below 90 K, 65.90 J/mol*K.; DH

Constant pressure heat capacity of liquid

C_p,liquid (cal/mol*K)	Temperature (K)	Reference	Comment
53.590	298.15	Huffman, Gross, et al., 1961	T = 10 to 300 K.; DH
52.80	294.4	Huffman, Parks, et al., 1930	T = 92 to 294 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
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
T_boil	353.7 ± 0.3	K	AVG	N/A	Average of 42 out of 48 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_fus	153. ± 3.	K	AVG	N/A	Average of 27 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_triple	154. ± 1.	K	AVG	N/A	Average of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_c	519.8 ± 0.5	K	N/A	Daubert, 1996
T_c	519.73	K	N/A	McMicking and Kay, 1965	Uncertainty assigned by TRC = 0.4 K; TRC
T_c	521.7	K	N/A	Francis, 1957	Uncertainty assigned by TRC = 2. K; TRC
T_c	520.25	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	27.0 ± 0.5	atm	N/A	Daubert, 1996
P_c	27.009	atm	N/A	McMicking and Kay, 1965	Uncertainty assigned by TRC = 0.4000 atm; TRC
P_c	27.400	atm	N/A	Edgar and Calingaert, 1929	Uncertainty assigned by TRC = 0.5000 atm; measured by Keys and Kleinschmidt; TRC
Quantity	Value	Units	Method	Reference	Comment
V_c	0.418	l/mol	N/A	Daubert, 1996
Quantity	Value	Units	Method	Reference	Comment
ρ_c	2.40 ± 0.05	mol/l	N/A	Daubert, 1996
ρ_c	2.40	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°	7.892	kcal/mol	N/A	Majer and Svoboda, 1985
Δ_vapH°	7.82 ± 0.02	kcal/mol	C	Svoboda, 1998	AC
Δ_vapH°	7.86 ± 0.02	kcal/mol	C	Osborne and Ginnings, 1947	AC
Δ_vapH°	7.859	kcal/mol	C	Osborne and Ginnings, 1947, 2	ALS

Enthalpy of vaporization

Δ_vapH (kcal/mol)	Temperature (K)	Method	Reference	Comment
7.063	353.7	N/A	Majer and Svoboda, 1985
7.72 ± 0.02	308.	C	Svoboda, 1998	AC
7.62 ± 0.02	315.	C	Svoboda, 1998	AC
7.53 ± 0.02	323.	C	Svoboda, 1998	AC
7.41 ± 0.02	330.	C	Svoboda, 1998	AC
7.31 ± 0.02	338.	C	Svoboda, 1998	AC
7.17 ± 0.02	348.	C	Svoboda, 1998	AC
7.96	299.	A	Stephenson and Malanowski, 1987	Based on data from 284. to 355. K. See also Kkykj and Repas, 1973.; AC
7.93	302.	N/A	Forziati, Norris, et al., 1949	Based on data from 287. to 354. K.; AC

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
286.86 to 354.52	3.9555	1197.608	-50.877	Forziati, Norris, et al., 1949, 2	Coefficents calculated by NIST from author's data.

Enthalpy of fusion

Δ_fusH (kcal/mol)	Temperature (K)	Reference	Comment
1.636	153.97	Huffman, Gross, et al., 1961	DH
1.64	154.	Domalski and Hearing, 1996	AC
1.600	152.5	Huffman, Parks, et al., 1930	DH

Entropy of fusion

Δ_fusS (cal/mol*K)	Temperature (K)	Reference	Comment
10.63	153.97	Huffman, Gross, et al., 1961	DH
10.49	152.5	Huffman, Parks, et al., 1930	DH

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:

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change 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 H.M., 1961
Huffman H.M., Low temperature thermodynamic properties of six isomeric heptanes, J. Phys. Chem., 1961, 65, 495-503. [all data]

Scott D.W., 1974
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]

Scott D.W., 1974, 2
Scott D.W., Correlation of the chemical thermodynamic properties of alkane hydrocarbons, J. Chem. Phys., 1974, 60, 3144-3165. [all data]

Huffman, Gross, et al., 1961
Huffman, H.M.; Gross, M.E.; Scott, D.W.; McCullough, I.P., Low temperature thermodynamic properties of six isomeric heptanes, J. Phys. Chem., 1961, 65, 495-503. [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]

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]

Francis, 1957
Francis, A.W., Pressure-Temperature-Liquid Density Relations of Pure Hydrocarbons, Ind. Eng. Chem., 1957, 49, 1779. [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 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]

Svoboda, 1998
Svoboda, V., Enthalpies of vaporization, and the cohesive and internal energies of 2,2-dimethylpentane, 2,4-dimethylpentane, 2,2,3-trimethylpentane, 2,3,3-trimethylpentane, and 3-ethylpentane, The Journal of Chemical Thermodynamics, 1998, 30, 11, 1411-1417, https://doi.org/10.1006/jcht.1998.0414 . [all data]

Osborne and Ginnings, 1947
Osborne, Nathan S.; Ginnings, Defoe C., Measurements of heat of vaporization and heat capacity of a number of hydrocarbons, J. RES. NATL. BUR. STAN., 1947, 39, 5, 453-17, https://doi.org/10.6028/jres.039.031 . [all data]

Osborne and Ginnings, 1947, 2
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]

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]

Kkykj and Repas, 1973
Kkykj, J.; Repas, M., Petrochemia, 1973, 13, 179. [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]

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, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, References

Symbols used in this document:

C_p,gas	Constant pressure heat capacity of gas
C_p,liquid	Constant pressure heat capacity of liquid
P_c	Critical pressure
S°_gas	Entropy of gas at standard conditions
S°_liquid	Entropy of liquid at standard conditions
T_boil	Boiling point
T_c	Critical temperature
T_fus	Fusion (melting) point
T_triple	Triple point temperature
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_fusH	Enthalpy of fusion
Δ_fusS	Entropy of fusion
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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