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
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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	-167.9 ± 0.63	kJ/mol	Ccb	Good, 1970	ALS
Δ_fH°_gas	-168.5 ± 1.0	kJ/mol	Cm	Pilcher and Chadwick, 1967	ALS
Δ_fH°_gas	-166.0 ± 1.0	kJ/mol	Ccb	Prosen and Rossini, 1945	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_gas	-3514.1 ± 0.96	kJ/mol	Cm	Pilcher and Chadwick, 1967	Corresponding Δ_fHº_gas = -168.5 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
120.82 ± 0.25	298.15	Hossenlopp I.A., 1981	GT
129.58 ± 0.26	323.15
138.41 ± 0.28	348.15
147.06 ± 0.29	373.15
155.46 ± 0.31	398.15
163.52 ± 0.32	423.15
171.46 ± 0.34	448.15
178.95 ± 0.36	473.15
186.42 ± 0.37	498.15
193.38 ± 0.39	523.15

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
80.54	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
111.63	273.15
120.83 ± 0.25	298.15
121.55	300.
155.98	400.
186.98	500.
214.64	600.
238.91	700.
261.08	800.
280.33	900.
297.90	1000.
313.38	1100.
327.19	1200.
338.90	1300.
351.46	1400.
359.82	1500.

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°	1711. ± 8.4	kJ/mol	Bran	DePuy, Gronert, et al., 1989	gas phase; B
Δ_rH°	1720. ± 42.	kJ/mol	CIDT	Graul and Squires, 1990	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1674. ± 8.8	kJ/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°	-669.6 ± 6.6	kJ/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]

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
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_fH°_gas	Enthalpy of formation of gas 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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