Neopentane

Formula: C₅H₁₂
Molecular weight: 72.1488
IUPAC Standard InChI: InChI=1S/C5H12/c1-5(2,3)4/h1-4H3
IUPAC Standard InChIKey: CRSOQBOWXPBRES-UHFFFAOYSA-N
CAS Registry Number: 463-82-1
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: Propane, 2,2-dimethyl-; tert-Pentane; Tetramethylcarbon; Tetramethylmethane; 1,1,1-Trimethylethane; 2,2-Dimethylpropane; Neo-C5H12; UN 2044; Dimethylpropane
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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
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-40.14 ± 0.15	kcal/mol	Ccb	Good, 1970	ALS
Δ_fH°_gas	-40.27 ± 0.24	kcal/mol	Cm	Pilcher and Chadwick, 1967	ALS
Δ_fH°_gas	-39.67 ± 0.25	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_gas	-839.88 ± 0.23	kcal/mol	Cm	Pilcher and Chadwick, 1967	Corresponding Δ_fHº_gas = -40.27 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
28.877 ± 0.060	298.15	Hossenlopp I.A., 1981	GT
30.970 ± 0.062	323.15
33.081 ± 0.067	348.15
35.148 ± 0.069	373.15
37.156 ± 0.074	398.15
39.082 ± 0.076	423.15
40.980 ± 0.081	448.15
42.770 ± 0.086	473.15
44.555 ± 0.088	498.15
46.219 ± 0.093	523.15

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
19.25	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 better agreement with experimental data than the statistical thermodynamics calculation [ Pitzer K.S., 1946].; GT
26.680	273.15
28.879 ± 0.060	298.15
29.051	300.
37.280	400.
44.689	500.
51.300	600.
57.101	700.
62.400	800.
67.000	900.
71.200	1000.
74.900	1100.
78.200	1200.
80.999	1300.
84.001	1400.
85.999	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	-45.49 ± 0.15	kcal/mol	Ccb	Good, 1970	ALS
Δ_fH°_liquid	-44.98 ± 0.25	kcal/mol	Ccb	Prosen and Rossini, 1945	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-834.71 ± 0.14	kcal/mol	Ccb	Good, 1970	Reanalyzed by Pedley, Naylor, et al., 1986, Original value = -834.66 ± 0.12 kcal/mol; Corresponding Δ_fHº_liquid = -45.44 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-835.18 ± 0.24	kcal/mol	Ccb	Prosen and Rossini, 1945	Corresponding Δ_fHº_liquid = -44.97 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	51.819	cal/mol*K	N/A	Enokida, Shinoda, et al., 1969	At normal boiling point.; DH
S°_liquid	52.29	cal/mol*K	N/A	Aston and Messerly, 1936	DH

Constant pressure heat capacity of liquid

C_p,liquid (cal/mol*K)	Temperature (K)	Reference	Comment
36.589	259.93	Enokida, Shinoda, et al., 1969	T = 4 to 260 K. Value is unsmoothed experimental datum.; DH
39.171	278.92	Aston and Messerly, 1936	T = 13 to 283 K. Value is unsmoothed experimental datum.; DH

Reaction thermochemistry data

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Data compiled as indicated in comments:
B - John E. Bartmess
MS - José A. Martinho Simões

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

C₅H₁₁^- + = Neopentane

By formula: C₅H₁₁^- + H⁺ = C₅H₁₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	408.9 ± 2.0	kcal/mol	Bran	DePuy, Gronert, et al., 1989	gas phase; B
Δ_rH°	411. ± 10.	kcal/mol	CIDT	Graul and Squires, 1990	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	400.1 ± 2.1	kcal/mol	H-TS	DePuy, Gronert, et al., 1989	gas phase; B

C₁₀H₂₂Mg (cr) + (g) + (l) = 2 Neopentane (l) + Br₂Mg (cr)

By formula: C₁₀H₂₂Mg (cr) + H₂ (g) + Br₂ (l) = 2C₅H₁₂ (l) + Br₂Mg (cr)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-160.0 ± 1.6	kcal/mol	RSC	Akkerman, Schat, et al., 1983	MS

Henry's Law data

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Data compiled by: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

k°_H (mol/(kg*bar))	d(ln(k_H))/d(1/T) (K)	Method	Reference	Comment
0.00047		Q	N/A	missing citation give several references for the Henry's law constants but don't assign them to specific species.
0.00027		L	N/A
0.00059	3400.	L	N/A
0.00046		V	N/A

References

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Good, 1970
Good, W.D., The enthalpies of combustion and formation of the isomeric pentanes, J. Chem. Thermodyn., 1970, 2, 237-244. [all data]

Pilcher and Chadwick, 1967
Pilcher, G.; Chadwick, J.D.M., Measurements of heats of combustion by flame calorimetry. Part 4.-n-Pentane, isopentane, neopentane, Trans. Faraday Soc., 1967, 63, 2357-2361. [all data]

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]

Hossenlopp I.A., 1981
Hossenlopp I.A., Vapor heat capacities and enthalpies of vaporization of five alkane hydrocarbons, J. Chem. Thermodyn., 1981, 13, 415-421. [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]

Pitzer K.S., 1946
Pitzer K.S., The entropies and related properties of branched paraffin hydrocarbons, Chem. Rev., 1946, 39, 435-447. [all data]

Pedley, Naylor, et al., 1986
Pedley, J.B.; Naylor, R.D.; Kirby, S.P., Thermochemical Data of Organic Compounds, Chapman and Hall, New York, 1986, 1-792. [all data]

Enokida, Shinoda, et al., 1969
Enokida, H.; Shinoda, T.; Mashiko, Y., Thermodynamic properties of neopentane from 4K to the melting point and comparison with spectroscopic data, Bull. Chem. Soc. Japan, 1969, 42, 84-91. [all data]

Aston and Messerly, 1936
Aston, J.G.; Messerly, G.H., Heat capacities and entropies of organic compounds. II. Thermal and vapor pressure data for tetramethylmethane from 13.22°K to the boiling point. The entropy from its Raman spectrum, J. Am. Chem. Soc., 1936, 58, 2354-2361. [all data]

DePuy, Gronert, et al., 1989
DePuy, C.H.; Gronert, S.; Barlow, S.E.; Bierbaum, V.M.; Damrauer, R., The Gas Phase Acidities of the Alkanes, J. Am. Chem. Soc., 1989, 111, 6, 1968, https://doi.org/10.1021/ja00188a003 . [all data]

Graul and Squires, 1990
Graul, S.T.; Squires, R.R., Gas-Phase Acidities Derived from Threshold Energies for Activated Reactions, J. Am. Chem. Soc., 1990, 112, 7, 2517, https://doi.org/10.1021/ja00163a007 . [all data]

Akkerman, Schat, et al., 1983
Akkerman, O.S.; Schat, G.; Evers, E.A.I.M.; Bickelhaupt, F., Recl. Trav. Chim. Pays-Bas, 1983, 102, 109. [all data]

Notes

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Symbols used in this document:

C_p,gas	Constant pressure heat capacity of gas
C_p,liquid	Constant pressure heat capacity of liquid
S°_liquid	Entropy of liquid at standard conditions
d(ln(k_H))/d(1/T)	Temperature dependence parameter for Henry's Law constant
k°_H	Henry's Law constant at 298.15K
Δ_cH°_gas	Enthalpy of combustion of gas at standard conditions
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_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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