Hexanoic acid

Formula: C₆H₁₂O₂
Molecular weight: 116.1583
IUPAC Standard InChI: InChI=1S/C6H12O2/c1-2-3-4-5-6(7)8/h2-5H2,1H3,(H,7,8)
IUPAC Standard InChIKey: FUZZWVXGSFPDMH-UHFFFAOYSA-N
CAS Registry Number: 142-62-1
Chemical structure:
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Other names: Caproic acid; n-Caproic acid; n-Hexanoic acid; n-Hexoic acid; n-Hexylic acid; Butylacetic acid; Capronic acid; Hexoic acid; Pentiformic acid; Pentylformic acid; 1-Pentanecarboxylic acid; CH3(CH2)4COOH; Pentane-1-carboxylic acid; 1-Hexanoic acid; Hexacid 698; Kyselina kapronova; Pentanecarboxylic acid; NSC 8266
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Gas phase thermochemistry data

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

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-512. ± 4.	kJ/mol	AVG	N/A	Average of 7 values; Individual data points

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	-581.8 ± 1.1	kJ/mol	Ccb	Fenwick, Harrop, et al., 1978	ALS
Δ_fH°_liquid	-583.58 ± 0.75	kJ/mol	Ccb	Adriaanse, Dekker, et al., 1965	Heat of formation derived by Cox and Pilcher, 1970; ALS
Δ_fH°_liquid	-585.68 ± 0.54	kJ/mol	Ccb	Lebedeva, 1964	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-3494.29 ± 0.66	kJ/mol	Ccb	Fenwick, Harrop, et al., 1978	Corresponding Δ_fHº_liquid = -581.75 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-3492.4 ± 0.6	kJ/mol	Ccb	Adriaanse, Dekker, et al., 1965	Corresponding Δ_fHº_liquid = -583.6 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-3490.4 ± 0.54	kJ/mol	Ccb	Lebedeva, 1964	Corresponding Δ_fHº_liquid = -585.63 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-3518.	kJ/mol	Ccb	Fischer and Wrede, 1904	Heat of combustion corrected for pressure; Corresponding Δ_fHº_liquid = -558.1 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_solid	-3522.8	kJ/mol	Ccb	Lemoult, 1904	Corresponding Δ_fHº_solid = -553.2 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS

Constant pressure heat capacity of liquid

C_p,liquid (J/mol*K)	Temperature (K)	Reference	Comment
225.1	298.	von Reis, 1881	T = 292 to 483 K.; DH

Reaction thermochemistry data

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Data compiled by: John E. Bartmess

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Individual Reactions

C₆H₁₁O₂^- + = Hexanoic acid

By formula: C₆H₁₁O₂^- + H⁺ = C₆H₁₂O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1448. ± 8.8	kJ/mol	G+TS	Caldwell, Renneboog, et al., 1989	gas phase
Δ_rH°	1447. ± 10.	kJ/mol	G+TS	McLuckey, Cameron, et al., 1981	gas phase
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1419. ± 8.4	kJ/mol	IMRE	Caldwell, Renneboog, et al., 1989	gas phase
Δ_rG°	1418. ± 9.6	kJ/mol	CIDC	McLuckey, Cameron, et al., 1981	gas phase

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
1200.	5900.	Q	N/A
1400.	6304.	M	N/A

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Henry's Law data, Notes

Fenwick, Harrop, et al., 1978
Fenwick, J.O.; Harrop, D.; Head, A.J., Thermodynamic properties of organic oxygen compounds. 46. Enthalpies of formation of ethyl acetate and 1-hexanoix acid, J. Chem. Thermodyn., 1978, 10, 687-690. [all data]

Adriaanse, Dekker, et al., 1965
Adriaanse, N.; Dekker, H.; Coops, J., Heats of combustion of normal saturated fatty acids and their methyl esters, Rec. Trav. Chim. Pays/Bas, 1965, 84, 393-407. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Lebedeva, 1964
Lebedeva, N.D., Heats of combustion of monocarboxylic acids, Russ. J. Phys. Chem. (Engl. Transl.), 1964, 38, 1435-1437. [all data]

Fischer and Wrede, 1904
Fischer, E.; Wrede, F., Uber die Verbrennungswarme einiger organischer Verbindungen, Sitzungsber. Dtsch. Akad. Wiss. Berlin Kl. Math. Phys. Tech., 1904, 687-715. [all data]

Lemoult, 1904
Lemoult, M.P., Remarques sur une serie recenie de determinations calorimetriques, Compt. Rend., 1904, 663-635. [all data]

von Reis, 1881
von Reis, M.A., Die specifische Wärme flüssiger organischer Verbindungen und ihre Beziehung zu deren Moleculargewicht, Ann. Physik [3], 1881, 13, 447-464. [all data]

Caldwell, Renneboog, et al., 1989
Caldwell, G.; Renneboog, R.; Kebarle, P., Gas Phase Acidities of Aliphatic Carboxylic Acids, Based on Measurements of Proton Transfer Equilibria, Can. J. Chem., 1989, 67, 4, 661, https://doi.org/10.1139/v89-092 . [all data]

McLuckey, Cameron, et al., 1981
McLuckey, S.A.; Cameron, D.; Cooks, R.G., Proton affinities from the dissociation of proton bound dimers, J. Am. Chem. Soc., 1981, 103, 1313. [all data]

Notes

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Symbols used in this document:

C_p,liquid	Constant pressure heat capacity of liquid
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°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_cH°_solid	Enthalpy of combustion of solid 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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