Acetic acid

Formula: C₂H₄O₂
Molecular weight: 60.0520
IUPAC Standard InChI: InChI=1S/C2H4O2/c1-2(3)4/h1H3,(H,3,4)
IUPAC Standard InChIKey: QTBSBXVTEAMEQO-UHFFFAOYSA-N
CAS Registry Number: 64-19-7
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.
Isotopologues:
- Acetic acid-d4
Other names: Ethanoic acid; Ethylic acid; Glacial acetic acid; Methanecarboxylic acid; Vinegar acid; CH3COOH; Acetasol; Acide acetique; Acido acetico; Azijnzuur; Essigsaeure; Octowy kwas; Acetic acid, glacial; Kyselina octova; UN 2789; Aci-jel; Shotgun; Ethanoic acid monomer; NSC 132953
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Information on this page:
Other data available:
- Gas phase thermochemistry data
- Condensed phase thermochemistry data
- Phase change data
- Reaction thermochemistry data: reactions 51 to 79
- Henry's Law data
- Ion clustering data
- IR Spectrum
- Mass spectrum (electron ionization)
- UV/Visible spectrum
- Vibrational and/or electronic energy levels
- Gas Chromatography
Data at other public NIST sites:
- Gas Phase Kinetics Database
- X-ray Photoelectron Spectroscopy Database, version 5.0
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Reaction thermochemistry data

Go To: Top, Gas phase ion energetics data, References, Notes

Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
ALS - 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.

Reactions 1 to 50

+ Acetic acid = ( • )

By formula: F^- + C₂H₄O₂ = (F^- • C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	185. ± 8.4	kJ/mol	IMRE	Larson and McMahon, 1983	gas phase; These relative affinities are ca. 10 kcal/mol weaker than threshold values (see Wenthold and Squires, 1995) for donors greater than ca. 27 kcal/mol in free energy. This discrepancy has not yet been resolved, though the stronger value appears preferable.; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	107.	J/mol*K	N/A	Larson and McMahon, 1983	gas phase; switching reaction(F-)H2O, Entropy change calculated or estimated; Arshadi, Yamdagni, et al., 1970; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	153. ± 8.4	kJ/mol	IMRE	Larson and McMahon, 1983	gas phase; These relative affinities are ca. 10 kcal/mol weaker than threshold values (see Wenthold and Squires, 1995) for donors greater than ca. 27 kcal/mol in free energy. This discrepancy has not yet been resolved, though the stronger value appears preferable.; B,M

C₂H₅O⁺ + Acetic acid = (C₂H₅O⁺ • )

By formula: C₂H₅O⁺ + C₂H₄O₂ = (C₂H₅O⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	118.	kJ/mol	PHPMS	Meot-Ner (Mautner), 1992	gas phase; M
Δ_rH°	123.	kJ/mol	ICR	Larson and McMahon, 1982	gas phase; switching reaction((CH3)2OH+)(CH3)2O, Entropy change calculated or estimated; Grimsrud and Kebarle, 1973, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	118.	J/mol*K	PHPMS	Meot-Ner (Mautner), 1992	gas phase; M
Δ_rS°	117.	J/mol*K	N/A	Larson and McMahon, 1982	gas phase; switching reaction((CH3)2OH+)(CH3)2O, Entropy change calculated or estimated; Grimsrud and Kebarle, 1973, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	88.7	kJ/mol	ICR	Larson and McMahon, 1982	gas phase; switching reaction((CH3)2OH+)(CH3)2O, Entropy change calculated or estimated; Grimsrud and Kebarle, 1973, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M

+ Acetic acid = ( • )

By formula: Cl^- + C₂H₄O₂ = (Cl^- • C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	102.1 ± 0.84	kJ/mol	TDAs	Sieck, 1985	gas phase; B,M
Δ_rH°	90.4 ± 8.4	kJ/mol	TDAs	Yamdagni and Kebarle, 1971	gas phase; B,M
Δ_rH°	100. ± 8.4	kJ/mol	IMRE	Larson and McMahon, 1984	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	82.0	J/mol*K	PHPMS	Sieck, 1985	gas phase; M
Δ_rS°	100.	J/mol*K	N/A	Larson and McMahon, 1984, 2	gas phase; switching reaction(Cl-)t-C4H9OH, Entropy change calculated or estimated; French, Ikuta, et al., 1982; M
Δ_rS°	80.8	J/mol*K	PHPMS	Yamdagni and Kebarle, 1971	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	77.8 ± 1.3	kJ/mol	TDAs	Sieck, 1985	gas phase; B
Δ_rG°	66.1 ± 8.4	kJ/mol	TDAs	Yamdagni and Kebarle, 1971	gas phase; B
Δ_rG°	69.9 ± 8.4	kJ/mol	IMRE	Larson and McMahon, 1984	gas phase; B,M

+ = Acetic acid

By formula: C₂H₃O₂^- + H⁺ = C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1457. ± 5.9	kJ/mol	CIDC	Angel and Ervin, 2006	gas phase; B
Δ_rH°	1456. ± 9.2	kJ/mol	G+TS	Taft and Topsom, 1987	gas phase; B
Δ_rH°	1459. ± 8.8	kJ/mol	G+TS	Cumming and Kebarle, 1978	gas phase; B
Δ_rH°	1459. ± 9.2	kJ/mol	G+TS	Fujio, McIver, et al., 1981	gas phase; value altered from reference due to change in acidity scale; B
Δ_rH°	1435.9 ± 2.9	kJ/mol	EIAE	Muftakhov, Vasil'ev, et al., 1999	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1427. ± 8.4	kJ/mol	IMRE	Taft and Topsom, 1987	gas phase; B
Δ_rG°	1429. ± 8.4	kJ/mol	IMRE	Cumming and Kebarle, 1978	gas phase; B
Δ_rG°	1430. ± 8.4	kJ/mol	IMRE	Fujio, McIver, et al., 1981	gas phase; value altered from reference due to change in acidity scale; B

C₂H₇O⁺ + Acetic acid = (C₂H₇O⁺ • )

By formula: C₂H₇O⁺ + C₂H₄O₂ = (C₂H₇O⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	123.	kJ/mol	ICR	Larson and McMahon, 1982	gas phase; switching reaction((CH3)2OH+)(CH3)2O, Entropy change calculated or estimated; Grimsrud and Kebarle, 1973, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	119.	J/mol*K	N/A	Larson and McMahon, 1982	gas phase; switching reaction((CH3)2OH+)(CH3)2O, Entropy change calculated or estimated; Grimsrud and Kebarle, 1973, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	87.0	kJ/mol	ICR	Larson and McMahon, 1982	gas phase; switching reaction((CH3)2OH+)(CH3)2O, Entropy change calculated or estimated; Grimsrud and Kebarle, 1973, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M

CH₆N⁺ + Acetic acid = (CH₆N⁺ • )

By formula: CH₆N⁺ + C₂H₄O₂ = (CH₆N⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds of the type NH+-O between organics

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	92.0	kJ/mol	PHPMS	Meot-Ner, 1984	gas phase; M
Δ_rH°	89.5	kJ/mol	PHPMS	Meot-Ner, 1984	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	102.	J/mol*K	PHPMS	Meot-Ner, 1984	gas phase; M
Δ_rS°	100.	J/mol*K	N/A	Meot-Ner, 1984	gas phase; Entropy change calculated or estimated; M

Free energy of reaction

Δ_rG° (kJ/mol)	T (K)	Method	Reference	Comment
43.1	459.	PHPMS	Meot-Ner, 1984	gas phase; Entropy change calculated or estimated; M

(C₂H₅O⁺ • 3 Acetic acid ) + = (C₂H₅O⁺ • 4)

By formula: (C₂H₅O⁺ • 3C₂H₄O₂) + C₂H₄O₂ = (C₂H₅O⁺ • 4C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	50.	kJ/mol	PHPMS	Meot-Ner (Mautner), 1992	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	100.	J/mol*K	N/A	Meot-Ner (Mautner), 1992	gas phase; Entropy change calculated or estimated; M

Free energy of reaction

Δ_rG° (kJ/mol)	T (K)	Method	Reference	Comment
26.	245.	PHPMS	Meot-Ner (Mautner), 1992	gas phase; Entropy change calculated or estimated; M

( • 2 Acetic acid • ) + = ( • 3 • )

By formula: (C₂H₃O₂^- • 2C₂H₄O₂ • H₂O) + C₂H₄O₂ = (C₂H₃O₂^- • 3C₂H₄O₂ • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	52.3 ± 2.5	kJ/mol	N/A	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rH°	67.8 ± 4.2	kJ/mol	TDAs	Meot-Ner and Sieck, 1986	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	24.0	kJ/mol	TDAs	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rG°	26. ± 4.2	kJ/mol	TDAs	Meot-Ner and Sieck, 1986	gas phase; B

( • Acetic acid • ) + = ( • 2 • )

By formula: (C₂H₃O₂^- • C₂H₄O₂ • H₂O) + C₂H₄O₂ = (C₂H₃O₂^- • 2C₂H₄O₂ • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	82.4 ± 2.1	kJ/mol	N/A	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rH°	67.8 ± 4.2	kJ/mol	TDAs	Meot-Ner and Sieck, 1986	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	45.23	kJ/mol	TDAs	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rG°	26. ± 4.2	kJ/mol	TDAs	Meot-Ner and Sieck, 1986	gas phase; B

+ = Acetic acid +

By formula: C₂H₃ClO + H₂O = C₂H₄O₂ + HCl

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-94.47	kJ/mol	Cm	Devore and O'Neal, 1969	liquid phase; Heat of hydrolysis; ALS
Δ_rH°	-92.30	kJ/mol	Cm	Pritchard and Skinner, 1950	liquid phase; Heat of hydrolysis at 298 K, see Carson and Skinner, 1949; ALS
Δ_rH°	-92.42	kJ/mol	Cm	Carson and Skinner, 1949	liquid phase; ALS

+ = 2 Acetic acid

By formula: C₄H₆O₃ + H₂O = 2C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-56.6 ± 4.0	kJ/mol	Cm	Becker and Maelicke, 1967	liquid phase; ALS
Δ_rH°	-58.6 ± 0.4	kJ/mol	Cm	Wadso, 1962	liquid phase; ALS
Δ_rH°	-58.4 ± 0.4	kJ/mol	Cm	Conn, Kistiakowsky, et al., 1942	liquid phase; Heat of hydrolysis at 303 K; ALS

+ Acetic acid = ( • )

By formula: I^- + C₂H₄O₂ = (I^- • C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	70.7 ± 4.2	kJ/mol	TDAs	Caldwell and Kebarle, 1984	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	89.1	J/mol*K	PHPMS	Caldwell and Kebarle, 1984	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	43.9 ± 4.2	kJ/mol	TDAs	Caldwell and Kebarle, 1984	gas phase; B

C₂H₃O₂^- + = Acetic acid

By formula: C₂H₃O₂^- + H⁺ = C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1540. ± 13.	kJ/mol	G+TS	Grabowski and Cheng, 1989	gas phase; B
Δ_rH°	1539. ± 19.	kJ/mol	EIAE	Muftakhov, Vasil'ev, et al., 1999	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1511. ± 13.	kJ/mol	IMRB	Grabowski and Cheng, 1989	gas phase; B

C₆H₅NO₂^- + Acetic acid = (C₆H₅NO₂^- • )

By formula: C₆H₅NO₂^- + C₂H₄O₂ = (C₆H₅NO₂^- • C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	94.56 ± 0.42	kJ/mol	TDAs	Sieck, 1985	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	112.	J/mol*K	PHPMS	Sieck, 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	61.09 ± 0.84	kJ/mol	TDAs	Sieck, 1985	gas phase; B

+ Acetic acid = ( • )

By formula: C₆H₅O^- + C₂H₄O₂ = (C₆H₅O^- • C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	115.	kJ/mol	PHPMS	Meot-Ner and Sieck, 1986	gas phase; calculated from CH3COO-.C6H5OH; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	100.	J/mol*K	PHPMS	Meot-Ner and Sieck, 1986	gas phase; calculated from CH3COO-.C6H5OH; M

(C₂H₅O⁺ • 2 Acetic acid ) + = (C₂H₅O⁺ • 3)

By formula: (C₂H₅O⁺ • 2C₂H₄O₂) + C₂H₄O₂ = (C₂H₅O⁺ • 3C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	54.8	kJ/mol	PHPMS	Meot-Ner (Mautner), 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	93.7	J/mol*K	PHPMS	Meot-Ner (Mautner), 1992	gas phase; M

(C₂H₅O⁺ • Acetic acid ) + = (C₂H₅O⁺ • 2)

By formula: (C₂H₅O⁺ • C₂H₄O₂) + C₂H₄O₂ = (C₂H₅O⁺ • 2C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	77.4	kJ/mol	PHPMS	Meot-Ner (Mautner), 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	103.	J/mol*K	PHPMS	Meot-Ner (Mautner), 1992	gas phase; M

C₆H₁₂NO₃⁺ + Acetic acid = (C₆H₁₂NO₃⁺ • )

By formula: C₆H₁₂NO₃⁺ + C₂H₄O₂ = (C₆H₁₂NO₃⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds with polydentate bonding in positive ions

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	75.7	kJ/mol	PHPMS	Meot-Ner, 1984, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	114.	J/mol*K	PHPMS	Meot-Ner, 1984, 2	gas phase; M

+ = + Acetic acid

By formula: C₄H₇NO₂ + H₂O = C₂H₅NO + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-18.1 ± 0.2	kJ/mol	Cm	Hill and Wadso, 1968	solid phase; Heat of hydrolysis; ALS
Δ_rH°	-18.1 ± 0.2	kJ/mol	Cm	Wadso, 1965	solid phase; Heat of hydrolysis; ALS

C₄H₁₀NO⁺ + Acetic acid = (C₄H₁₀NO⁺ • )

By formula: C₄H₁₀NO⁺ + C₂H₄O₂ = (C₄H₁₀NO⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	77.0	kJ/mol	PHPMS	Meot-Ner, 1984, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	103.	J/mol*K	PHPMS	Meot-Ner, 1984, 2	gas phase; M

+ = + Acetic acid

By formula: C₂H₃IO + H₂O = HI + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-93.97	kJ/mol	Cm	Devore and O'Neal, 1969	liquid phase; Heat of hydrolysis; ALS
Δ_rH°	-90.33	kJ/mol	Cm	Carson and Skinner, 1949	liquid phase; Heat of hydrolysis; ALS

( • ) + Acetic acid = ( • • )

By formula: (C₂H₃O₂^- • H₂O) + C₂H₄O₂ = (C₂H₃O₂^- • C₂H₄O₂ • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	123. ± 4.2	kJ/mol	TDAs	Meot-Ner and Sieck, 1986	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	85.4 ± 6.7	kJ/mol	TDAs	Meot-Ner and Sieck, 1986	gas phase; B

+ = + Acetic acid

By formula: C₄H₆O₃ + C₄H₁₁N = C₆H₁₃NO + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-113.2 ± 0.46	kJ/mol	Cm	Wadso, 1962	liquid phase; ALS
Δ_rH°	-163.7 ± 0.3	kJ/mol	Cm	Wadso, 1958	liquid phase; Heat of aminolysis; ALS

+ = + Acetic acid

By formula: C₂H₃BrO + H₂O = HBr + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-97.53	kJ/mol	Cm	Devore and O'Neal, 1969	liquid phase; Heat of hydrolysis; ALS
Δ_rH°	-96.48	kJ/mol	Cm	Carson and Skinner, 1949	liquid phase; ALS

+ Acetic acid = C₈H₉O₂S^-

By formula: C₆H₅S^- + C₂H₄O₂ = C₈H₉O₂S^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	84.94 ± 0.42	kJ/mol	TDAs	Sieck and Meot-ner, 1989	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	52.3 ± 1.7	kJ/mol	TDAs	Sieck and Meot-ner, 1989	gas phase; B

( • 2 Acetic acid ) + = ( • 3)

By formula: (C₂H₃O₂^- • 2C₂H₄O₂) + C₂H₄O₂ = (C₂H₃O₂^- • 3C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	67.8	kJ/mol	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	139.	J/mol*K	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M

( • Acetic acid ) + = ( • 2)

By formula: (C₂H₃O₂^- • C₂H₄O₂) + C₂H₄O₂ = (C₂H₃O₂^- • 2C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	82.0	kJ/mol	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	120.	J/mol*K	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M

+ Acetic acid = ( • )

By formula: C₆H₅S^- + C₂H₄O₂ = (C₆H₅S^- • C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	84.9	kJ/mol	PHPMS	Sieck and Meot-ner, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	110.	J/mol*K	PHPMS	Sieck and Meot-ner, 1989	gas phase; M

+ Acetic acid = ( • )

By formula: Li⁺ + C₂H₄O₂ = (Li⁺ • C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	174.	kJ/mol	ICR	Staley and Beauchamp, 1975	gas phase; switching reaction(Li+)H2O, from graph; Dzidic and Kebarle, 1970 interpolated; M

+ Acetic acid = ( • )

By formula: C₂H₃O₂^- + C₂H₄O₂ = (C₂H₃O₂^- • C₂H₄O₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	123.	kJ/mol	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	124.	J/mol*K	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M

+ 2 = + 2 Acetic acid

By formula: C₈H₁₄O₄ + 2H₂O = C₄H₁₀O₂ + 2C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-22.3 ± 2.1	kJ/mol	Cm	Shlechter, Othmer, et al., 1945	liquid phase; Heat of formation derived by Cox and Pilcher, 1970; ALS

+ = + Acetic acid

By formula: C₅H₆N₂O + H₂O = C₃H₄N₂ + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-20.2 ± 0.2	kJ/mol	Cm	Wadso, 1960	liquid phase; solvent: Aqueous; Heat of hydrolysis; ALS

+ 2 Acetic acid = + 2

By formula: C₄H₁₀O₂ + 2C₂H₄O₂ = C₈H₁₄O₄ + 2H₂O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	22.30	kJ/mol	Eqk	Shlechter, Othmer, et al., 1945	liquid phase; Heat of esterification at 338-453 K; ALS

+ Acetic acid = +

By formula: C₆H₁₂O₃ + C₂H₄O₂ = C₈H₁₄O₄ + H₂O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.85	kJ/mol	Eqk	Shlechter, Othmer, et al., 1945	liquid phase; Heat of esterification at 338-453 K; ALS

+ 2 = + 2 Acetic acid

By formula: C₆H₉NO₃ + 2H₂O = C₂H₅NO + 2C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-103.5 ± 0.08	kJ/mol	Cm	Hill and Wadso, 1968	liquid phase; Heat of hydrolysis; ALS

2 + = Acetic acid + 2

By formula: 2H₂O + C₄H₈O₂ = C₂H₄O₂ + 2CH₄O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-74.4 ± 3.6	kJ/mol	Cm	Guthrie and Liu, 1995	liquid phase; Heat of hydrolysis; ALS

+ Acetic acid =

By formula: C₁₀H₁₄ + C₂H₄O₂ = C₁₂H₁₈O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-182.0 ± 0.3	kJ/mol	Cac	Wiberg, Connon, et al., 1979	liquid phase; solvent: Acetic acid; ALS

+ = Acetic acid +

By formula: C₂H₄OS + H₂O = C₂H₄O₂ + H₂S

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-2.7 ± 0.3	kJ/mol	Cm	Sunner and Wadso, 1957	liquid phase; Heat of hydrolysis; ALS

+ = Acetic acid +

By formula: C₂H₅NO + H₂O = C₂H₄O₂ + H₃N

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	76.1 ± 1.4	kJ/mol	Cm	Hill and Wadso, 1968	solid phase; Heat of hydrolysis; ALS

+ Acetic acid = +

By formula: C₆H₁₃NO + C₂H₄O₂ = C₈H₁₅NO₂ + H₂O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	40.5 ± 0.50	kJ/mol	Cm	Wadso, 1965	liquid phase; Heat of hydrolysis; ALS

+ = + Acetic acid

By formula: C₅H₁₀OS + H₂O = C₃H₈S + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-3.9 ± 0.3	kJ/mol	Cm	Wadso, 1957	liquid phase; Heat of hydrolysis; ALS

+ Acetic acid = C₁₀H₁₁NO₂ +

By formula: C₈H₉NO + C₂H₄O₂ = C₁₀H₁₁NO₂ + H₂O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	45.5 ± 0.3	kJ/mol	Cm	Wadso, 1965	solid phase; Heat of hydrolysis; ALS

+ = + Acetic acid

By formula: C₉H₁₀O₂ + H₂O = C₇H₈O + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-18.4 ± 0.59	kJ/mol	Cm	Sunner, 1957	liquid phase; Heat of hydrolysis; ALS

+ = + Acetic acid

By formula: H₂O + C₆H₁₂OS = C₄H₁₀S + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-4.6 ± 0.3	kJ/mol	Cm	Wadso, 1957	liquid phase; Heat of hydrolysis; ALS

+ = + Acetic acid

By formula: C₃H₄N₄O + H₂O = CH₂N₄ + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-43.1 ± 0.4	kJ/mol	Cm	Wadso, 1960	solid phase; Heat of hydrolysis; ALS

+ = + Acetic acid

By formula: C₉H₈O₃S + H₂O = C₇H₆O₂S + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-11.5 ± 0.4	kJ/mol	Cm	Nelander, 1964	solid phase; Heat of hydrolysis; ALS

+ = + Acetic acid

By formula: C₈H₉NO + H₂O = C₆H₇N + C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-42.0 ± 0.3	kJ/mol	Cm	Wadso, 1965	solid phase; Heat of hydrolysis; ALS

Acetic acid + = +

By formula: C₂H₄O₂ + C₃H₆O = C₅H₈O₂ + H₂O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	60.2 ± 0.3	kJ/mol	Cm	Sunner, 1957	liquid phase; Heat of hydrolysis; ALS

+ = Acetic acid +

By formula: C₄H₈OS + H₂O = C₂H₄O₂ + C₂H₆S

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-4.0 ± 0.3	kJ/mol	Cm	Wadso, 1957	liquid phase; Heat of hydrolysis; ALS

+ = Acetic acid +

By formula: H₂O + C₅H₁₀OS = C₂H₄O₂ + C₃H₈S

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-5.8 ± 0.3	kJ/mol	Cm	Wadso, 1957	liquid phase; Heat of hydrolysis; ALS

Gas phase ion energetics data

Go To: Top, Reaction thermochemistry data, References, Notes

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
LL - Sharon G. Lias and Joel F. Liebman

View reactions leading to C₂H₄O₂⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	10.65 ± 0.02	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	783.7	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	752.8	kJ/mol	N/A	Hunter and Lias, 1998	HL

Ionization energy determinations

IE (eV)	Method	Reference	Comment
10.63	PI	Traeger, McLouglin, et al., 1982	LBLHLM
10.66	EI	Holmes, Fingas, et al., 1981	LLK
10.66 ± 0.05	EI	Holmes and Lossing, 1980	LLK
10.66	EI	Holmes and Lossing, 1980, 2	LLK
10.66 ± 0.05	PI	Akopyan and Villem, 1976	LLK
10.664 ± 0.003	PI	Watanabe, Yokoyama, et al., 1974	LLK
10.644 ± 0.002	PI	Knowles and Nicholson, 1974	LLK
10.65	PE	Watanabe, Yokoyama, et al., 1973	LLK
10.69 ± 0.03	PE	Thomas, 1972	LLK
10.70	PE	Sweigart and Turner, 1972	LLK
10.37 ± 0.03	PI	Watanabe, Nakayama, et al., 1962	RDSH
10.38 ± 0.03	PI	Vilesov, 1960	RDSH
10.35 ± 0.03	PI	Watanabe, 1957	RDSH
10.9	PE	Von Niessen, Bieri, et al., 1980	Vertical value; LLK
10.84	PE	Carnovale, Gan, et al., 1980	Vertical value; LLK
10.63	PE	Benoit and Harrison, 1977	Vertical value; LLK
11.5	PE	Rao, 1975	Vertical value; LLK
10.87	PE	Kimura, Katsumata, et al., 1975	Vertical value; LLK
10.8	PE	Green and Hayes, 1975	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C⁺	22.0 ± 0.5	H₂+HCOOH	EI	Stepanov, Perov, et al., 1988	LL
CHO₂⁺	12.27 ± 0.05	CH₃	EI	Haney and Franklin, 1969	RDSH
CHO₂⁺	12.9 ± 0.1	CH₃	EI	Shigorin, Filyugina, et al., 1966	RDSH
CH₃⁺	14.0 ± 0.15	?	EI	Haney and Franklin, 1969	RDSH
CH₃O⁺	12.05 ± 0.10	CHO	EI	Selim and Helal, 1981	LLK
CO⁺	15.3 ± 0.1	CH₃OH	EI	Shigorin, Filyugina, et al., 1966	RDSH
C₂H₃O⁺	11.54	OH	PI	Traeger, McLouglin, et al., 1982	LBLHLM
C₂H₃O⁺	11.75	OH	EI	Haney and Franklin, 1969	RDSH
C₂H₃O⁺	11.4 ± 0.15	OH	EI	Shigorin, Filyugina, et al., 1966	RDSH
OH⁺	15.1	?	EI	Majer, Patrick, et al., 1961	RDSH

De-protonation reactions

+ = Acetic acid

By formula: C₂H₃O₂^- + H⁺ = C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1457. ± 5.9	kJ/mol	CIDC	Angel and Ervin, 2006	gas phase; B
Δ_rH°	1456. ± 9.2	kJ/mol	G+TS	Taft and Topsom, 1987	gas phase; B
Δ_rH°	1459. ± 8.8	kJ/mol	G+TS	Cumming and Kebarle, 1978	gas phase; B
Δ_rH°	1459. ± 9.2	kJ/mol	G+TS	Fujio, McIver, et al., 1981	gas phase; value altered from reference due to change in acidity scale; B
Δ_rH°	1435.9 ± 2.9	kJ/mol	EIAE	Muftakhov, Vasil'ev, et al., 1999	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1427. ± 8.4	kJ/mol	IMRE	Taft and Topsom, 1987	gas phase; B
Δ_rG°	1429. ± 8.4	kJ/mol	IMRE	Cumming and Kebarle, 1978	gas phase; B
Δ_rG°	1430. ± 8.4	kJ/mol	IMRE	Fujio, McIver, et al., 1981	gas phase; value altered from reference due to change in acidity scale; B

C₂H₃O₂^- + = Acetic acid

By formula: C₂H₃O₂^- + H⁺ = C₂H₄O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1540. ± 13.	kJ/mol	G+TS	Grabowski and Cheng, 1989	gas phase; B
Δ_rH°	1539. ± 19.	kJ/mol	EIAE	Muftakhov, Vasil'ev, et al., 1999	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1511. ± 13.	kJ/mol	IMRB	Grabowski and Cheng, 1989	gas phase; B

References

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Notes

Larson and McMahon, 1983
Larson, J.W.; McMahon, T.B., Strong hydrogen bonding in gas-phase anions. An ion cyclotron resonance determination of fluoride binding energetics to bronsted acids from gas-phase fluoride exchange equilibria measurements, J. Am. Chem. Soc., 1983, 105, 2944. [all data]

Wenthold and Squires, 1995
Wenthold, P.G.; Squires, R.R., Bond dissociation energies of F2(-) and HF2(-). A gas-phase experimental and G2 theoretical study, J. Phys. Chem., 1995, 99, 7, 2002, https://doi.org/10.1021/j100007a034 . [all data]

Arshadi, Yamdagni, et al., 1970
Arshadi, M.; Yamdagni, R.; Kebarle, P., Hydration of Halide Negative Ions in the Gas Phase. II. Comparison of Hydration Energies for the Alkali Positive and Halide Negative Ions, J. Phys. Chem., 1970, 74, 7, 1475, https://doi.org/10.1021/j100702a014 . [all data]

Meot-Ner (Mautner), 1992
Meot-Ner (Mautner), M., Intermolecular Forces in Organic Clusters, J. Am. Chem. Soc., 1992, 114, 9, 3312, https://doi.org/10.1021/ja00035a024 . [all data]

Larson and McMahon, 1982
Larson, J.W.; McMahon, T.B., Formation, Thermochemistry, and Relative Stabilities of Proton - Bound dimers of Oxygen n - Donor Bases from Ion Cyclotron Resonance Solvent - Exchange Equilibria Measurements, J. Am. Chem. Soc., 1982, 104, 23, 6255, https://doi.org/10.1021/ja00387a016 . [all data]

Grimsrud and Kebarle, 1973
Grimsrud, E.P.; Kebarle, P., Gas Phase Ion Equilibria Studies of the Solvation of the Hydrogen Ion by Methanol, Dimethyl Ether and Water. Effect of Hydrogen Bonding, J. Am. Chem. Soc., 1973, 95, 24, 7939, https://doi.org/10.1021/ja00805a002 . [all data]

Lias, Liebman, et al., 1984
Lias, S.G.; Liebman, J.F.; Levin, R.D., Evaluated gas phase basicities and proton affinities of molecules heats of formation of protonated molecules, J. Phys. Chem. Ref. Data, 1984, 13, 695. [all data]

Keesee and Castleman, 1986
Keesee, R.G.; Castleman, A.W., Jr., Thermochemical data on Ggs-phase ion-molecule association and clustering reactions, J. Phys. Chem. Ref. Data, 1986, 15, 1011. [all data]

Sieck, 1985
Sieck, L.W., Thermochemistry of Solvation of NO₂^- and C₆H₅NO₂^- by Polar Molecules in the Vapor Phase. Comparison with Cl^- and Variation with Ligand Structure., J. Phys. Chem., 1985, 89, 25, 5552, https://doi.org/10.1021/j100271a049 . [all data]

Yamdagni and Kebarle, 1971
Yamdagni, R.; Kebarle, P., Hydrogen bonding energies to negative ions from gas phase measurements of ionic equilibria, J. Am. Chem. Soc., 1971, 93, 7139. [all data]

Larson and McMahon, 1984
Larson, J.W.; McMahon, T.B., Hydrogen bonding in gas phase anions. An experimental investigation of the interaction between chloride ion and bronsted acids from ICR chloride exchange equilibria, J. Am. Chem. Soc., 1984, 106, 517. [all data]

Larson and McMahon, 1984, 2
Larson, J.W.; McMahon, T.B., Gas phase negative ion chemistry of alkylchloroformates, Can. J. Chem., 1984, 62, 675. [all data]

French, Ikuta, et al., 1982
French, M.A.; Ikuta, S.; Kebarle, P., Hydrogen bonding of O-H and C-H hydrogen donors to Cl^-. Results from mass spectrometric measurement of the ion-molecule equilibria RH + Cl^- = RHCl^-, Can. J. Chem., 1982, 60, 1907. [all data]

Angel and Ervin, 2006
Angel, L.A.; Ervin, K.M., Gas-phase acidities and O-H bond dissociation enthalpies of phenol, 3-methylphenol, 2,4,6-trimethylphenol, and ethanoic acid, J. Phys. Chem. A, 2006, 110, 35, 10392-10403, https://doi.org/10.1021/jp0627426 . [all data]

Taft and Topsom, 1987
Taft, R.W.; Topsom, R.D., The Nature and Analysis of Substituent Effects, Prog. Phys. Org. Chem., 1987, 16, 1. [all data]

Cumming and Kebarle, 1978
Cumming, J.B.; Kebarle, P., Summary of gas phase measurements involving acids AH. Entropy changes in proton transfer reactions involving negative ions. Bond dissociation energies D(A-H) and electron affinities EA(A), Can. J. Chem., 1978, 56, 1. [all data]

Fujio, McIver, et al., 1981
Fujio, M.; McIver, R.T., Jr.; Taft, R.W., Effects on the acidities of phenols from specific substituent-solvent interactions. Inherent substituent parameters from gas phase acidities, J. Am. Chem. Soc., 1981, 103, 4017. [all data]

Muftakhov, Vasil'ev, et al., 1999
Muftakhov, M.V.; Vasil'ev, Y.V.; Mazunov, V.A., Determination of electron affinity of carbonyl radicals by means of negative ion mass spectrometry, Rapid Commun. Mass Spectrom., 1999, 13, 12, 1104-1108, https://doi.org/10.1002/(SICI)1097-0231(19990630)13:12<1104::AID-RCM619>3.0.CO;2-C . [all data]

Meot-Ner, 1984
Meot-Ner, (Mautner)M., The Ionic Hydrogen Bond and Ion Solvation. 1. -NH+ O-, -NH+ N- and -OH+ O- Bonds. Correlations with Proton Affinity. Deviations Due to Structural Effects, J. Am. Chem. Soc., 1984, 106, 5, 1257, https://doi.org/10.1021/ja00317a015 . [all data]

Meot-ner, Elmore, et al., 1999
Meot-ner, M.; Elmore, D.E.; Scheiner, S., Ionic Hydrogen Bond Effects on the Acidities, Basicities, Solvation, Solvent Bridging and Self-assembly of Carboxylic Groups, J. Am. Chem. Soc., 1999, 121, 33, 7625, https://doi.org/10.1021/ja982173i . [all data]

Meot-Ner and Sieck, 1986
Meot-Ner, M.; Sieck, L.W., The ionic hydrogen bond and ion solvation. 5. OH...O^- bonds. Gas phase solvation and clustering of alkoxide and carboxylate anions, J. Am. Chem. Soc., 1986, 108, 7525. [all data]

Devore and O'Neal, 1969
Devore, J.A.; O'Neal, H.E., Heats of formation of the acetyl halides and of the acetyl radical, J. Phys. Chem., 1969, 73, 2644-2648. [all data]

Pritchard and Skinner, 1950
Pritchard, H.O.; Skinner, H.A., The heats of hydrolysis of the chloro-substituted acetyl chlorides, J. Chem. Soc., 1950, 272-276. [all data]

Carson and Skinner, 1949
Carson, A.S.; Skinner, H.A., 201. Carbon-halogen bond energies in the acetyl halides, J. Chem. Soc., 1949, 936-939. [all data]

Becker and Maelicke, 1967
Becker, F.; Maelicke, A., Thermokinetische Messungen nach dem Prinzip der Wärmefluβkalorimetrie, Z. Phys. Chem. (Neue Folge), 1967, 55, 280-295. [all data]

Wadso, 1962
Wadso, I., Heats of aminolysis and hydrolysis of some N-acetyl compounds and of acetic anhydride, Acta Chem. Scand., 1962, 16, 471-478. [all data]

Conn, Kistiakowsky, et al., 1942
Conn, J.B.; Kistiakowsky, G.B.; Roberts, R.M.; Smith, E.A., Heats of organic reactions. XIII. Heats of hydrolysis of some acid anhydrides, J. Am. Chem. Soc., 1942, 64, 1747-17. [all data]

Caldwell and Kebarle, 1984
Caldwell, G.; Kebarle, P., Binding energies and structural effects in halide anion-ROH and -RCOOH complexes from gas phase equilibria measurements, J. Am. Chem. Soc., 1984, 106, 967. [all data]

Grabowski and Cheng, 1989
Grabowski, J.J.; Cheng, X., Gas-Phase Formation of the Enolate Monoanion of Acetic Acid by Proton Abstraction, J. Am. Chem. Soc., 1989, 111, 8, 3106, https://doi.org/10.1021/ja00190a078 . [all data]

Meot-Ner, 1984, 2
Meot-Ner, (Mautner), The Ionic Hydrogen Bond. 4. Intramolecular and Multiple Bonds. Proton Affinities, Hydration and Complexes of Amides and Amino Acid Derivatives, J. Am. Chem. Soc., 1984, 106, 2, 278, https://doi.org/10.1021/ja00314a003 . [all data]

Hill and Wadso, 1968
Hill, J.O.; Wadso, I., Some thermochemical properties of N,N,N-triacetylammonia, Acta Chem. Scand., 1968, 22, 1590-1594. [all data]

Wadso, 1965
Wadso, I., Thermochemical properties of diacetimide, N-butyldiacetimide and N-phenyldiacetimide, Acta Chem. Scand., 1965, 19, 1079-1087. [all data]

Wadso, 1958
Wadso, I., The heats of aminolysis of n-butyl thiolacetate and acetic anhydride, Acta Chem. Scand., 1958, 12, 635-640. [all data]

Sieck and Meot-ner, 1989
Sieck, L.W.; Meot-ner, M., Ionic Hydrogen Bond and Ion Solvation. 8. RS-..HOR Bond Strengths. Correlation with Acidities., J. Phys. Chem., 1989, 93, 4, 1586, https://doi.org/10.1021/j100341a079 . [all data]

Staley and Beauchamp, 1975
Staley, R.H.; Beauchamp, J.L., Intrinsic Acid - Base Properties of Molecules. Binding Energies of Li+ to pi - and n - Donor Bases, J. Am. Chem. Soc., 1975, 97, 20, 5920, https://doi.org/10.1021/ja00853a050 . [all data]

Dzidic and Kebarle, 1970
Dzidic, I.; Kebarle, P., Hydration of the Alkali Ions in the Gas Phase. Enthalpies and Entropies of Reactions M+(H2O)n-1 + H2O = M+(H2O)n, J. Phys. Chem., 1970, 74, 7, 1466, https://doi.org/10.1021/j100702a013 . [all data]

Shlechter, Othmer, et al., 1945
Shlechter, N.; Othmer, D.F.; Marshak, S., Esterification of 2,3-butylene glycol with acetic acid, Ind. Eng. Chem., 1945, 37, 900-905. [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]

Wadso, 1960
Wadso, I., Heats of hydrolysis of N-acetylated imidazole, 1,2,4-triazole and tetrazole, Acta Chem. Scand., 1960, 14, 903-908. [all data]

Guthrie and Liu, 1995
Guthrie, J.P.; Liu, Z., The enols of acetic acid and methyl acetate, Can. J. Chem., 1995, 73, 1395-2398. [all data]

Wiberg, Connon, et al., 1979
Wiberg, K.B.; Connon, H.A.; Pratt, W.E., Enthalpies of acetolysis of tricyclo[3.2.1.0^1,5]octane ([3.2.1]propellane) and 1,3-dehydroadamantane, J. Am. Chem. Soc., 1979, 101, 6970-6972. [all data]

Sunner and Wadso, 1957
Sunner, S.; Wadso, I., The heat of hydrolysis of thiolacetic acid, Trans. Faraday Soc., 1957, 53, 455-459. [all data]

Wadso, 1957
Wadso, I., The heats of hydrolysis of some alkyl thiolesters, Acta Chem. Scand., 1957, 11, 1745-1751. [all data]

Sunner, 1957
Sunner, S., The heat of hydrolysis of i-propenyl acetate and m-cresyl acetate and the heat of formation of acetone, Acta Chem. Scand., 1957, 11, 1757-1760. [all data]

Nelander, 1964
Nelander, L., The heats of hydrolysis of aspirin, thioaspirin, and their p-analogues, Acta Chem. Scand., 1964, 18, 973-984. [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Traeger, McLouglin, et al., 1982
Traeger, J.C.; McLouglin, R.G.; Nicholson, A.J.C., Heat of formation for acetyl cation in the gas phase, J. Am. Chem. Soc., 1982, 104, 5318. [all data]

Holmes, Fingas, et al., 1981
Holmes, J.L.; Fingas, M.; Lossing, F.P., Towards a general scheme for estimating the heats of formation of organic ions in the gas phase. Part I. Odd-electron cations, Can. J. Chem., 1981, 59, 80. [all data]

Holmes and Lossing, 1980
Holmes, J.L.; Lossing, F.P., Thermochemistry and unimolecular reactions of ionized acetic acid and its enol in the gas phase., J. Am. Chem. Soc., 1980, 102, 3732. [all data]

Holmes and Lossing, 1980, 2
Holmes, J.L.; Lossing, F.P., Gas-phase heats of formation of keto and enol ions of carbonyl compounds., J. Am. Chem. Soc., 1980, 102, 1591. [all data]

Akopyan and Villem, 1976
Akopyan, M.E.; Villem, Ya.Ya., Ion-molecule reactions in the photoionization of formic and acetic acid vapors, High Energy Chem., 1976, 10, 24. [all data]

Watanabe, Yokoyama, et al., 1974
Watanabe, I.; Yokoyama, Y.; Ikeda, S., Vibrational structures in the He(I) photoelectron spectra of carboxylic acids, Bull. Chem. Soc. Jpn., 1974, 47, 627. [all data]

Knowles and Nicholson, 1974
Knowles, D.J.; Nicholson, A.J.C., Ionization energies of formic and acetic acid monomers, J. Chem. Phys., 1974, 60, 1180. [all data]

Watanabe, Yokoyama, et al., 1973
Watanabe, I.; Yokoyama, Y.; Ikeda, S., Lone pair ionization potentials of carboxylic acids determined by He(I) photoelectron spectroscopy, Bull. Chem. Soc. Jpn., 1973, 46, 1959. [all data]

Thomas, 1972
Thomas, R.K., Photoelectron spectroscopy of hydrogen-bonded systems: spectra of monomers, dimers and mixed complexes of carboxylic acides, Proc. R. Soc. London A:, 1972, 331, 249. [all data]

Sweigart and Turner, 1972
Sweigart, D.A.; Turner, D.W., Lone pair orbitals and their interactions studied by photoelectron spectroscopy. I. Carboxylic acids and their derivatives, J. Am. Chem. Soc., 1972, 94, 5592. [all data]

Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J., Ionization potentials of some molecules, J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]

Vilesov, 1960
Vilesov, F.I., The photoionization of vapors of compounds whose molecules contain carbonyl groups, Dokl. Phys. Chem., 1960, 132, 521, In original 1332. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Von Niessen, Bieri, et al., 1980
Von Niessen, W.; Bieri, G.; Asbrink, L., 30.4 nm He(II) photoelectron spectra of organic molecules. Part III. Oxo-compounds (C,H,O), J. Electron Spectrosc. Relat. Phenom., 1980, 21, 175. [all data]

Carnovale, Gan, et al., 1980
Carnovale, F.; Gan, T.H.; Peel, J.B., Photoelectron spectroscopic studies of the monomers and dimers of acetic and trifluoracetic acids, J. Electron Spectrosc. Relat. Phenom., 1980, 20, 53. [all data]

Benoit and Harrison, 1977
Benoit, F.M.; Harrison, A.G., Predictive value of proton affinity. Ionization energy correlations involving oxygenated molecules, J. Am. Chem. Soc., 1977, 99, 3980. [all data]

Rao, 1975
Rao, C.N.R., Lone-pair ionization bands of chromophores in the photoelectron spectra of organic molecules, Indian J. Chem., 1975, 13, 950. [all data]

Kimura, Katsumata, et al., 1975
Kimura, K.; Katsumata, S.; Yamazaki, T.; Wakabayashi, H., UV photoelectron spectra and sum rule consideration; out-of-plane orbitals of unsaturated compounds with planar-skeleton structure, J. Electron Spectrosc. Relat. Phenom., 1975, 6, 41. [all data]

Green and Hayes, 1975
Green, J.C.; Hayes, A.J., Ionization energies of an Mo-Mo quadruple bond; a He(I) photoelectron study of some molybdenum-dycarboxylate dimers, Chem. Phys. Lett., 1975, 31, 306. [all data]

Stepanov, Perov, et al., 1988
Stepanov, A.N.; Perov, A.A.; Kabanov, S.P.; Simonov, A.P., Formation of long-lived, highly excited atoms during dissociative excitation of CH₃CN, CH₃CH₂OH, CH₃COOH, HCOOH, and C₄H₄S molecules on electron impact, Russ. J. Phys. Chem., 1988, 22, 81. [all data]

Haney and Franklin, 1969
Haney, M.A.; Franklin, J.L., Excess energies in mass spectra of some oxygen-containing organic compounds, J. Chem. Soc. Faraday Trans., 1969, 65, 1794. [all data]

Shigorin, Filyugina, et al., 1966
Shigorin, D.N.; Filyugina, A.D.; Potapov, V.K., Ionization and dissociation of molecules of acetaldehyde, acetone, and acetic acid on electron impact, Teor. i Eksperim. Khim., 1966, 2, 554, In original 417. [all data]

Selim and Helal, 1981
Selim, E.T.M.; Helal, A.I., Heat of formation of CH₂=OH⁺ fragment ion, Indian J. Pure Appl. Phys., 1981, 19, 977. [all data]

Majer, Patrick, et al., 1961
Majer, J.R.; Patrick, C.R.; Robb, J.C., Appearance potentials of the acetyl radical-ion, J. Chem. Soc. Faraday Trans., 1961, 57, 14. [all data]

Notes

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Symbols used in this document:

AE	Appearance energy
IE (evaluated)	Recommended ionization energy
T	Temperature
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions
Δ_rS°	Entropy of reaction at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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