Acetylacetone
- Formula: C5H8O2
- Molecular weight: 100.1158
- IUPAC Standard InChI: InChI=1S/C5H8O2/c1-4(6)3-5(2)7/h3H2,1-2H3
- IUPAC Standard InChIKey: YRKCREAYFQTBPV-UHFFFAOYSA-N
- CAS Registry Number: 123-54-6
- 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-Pentanedione; Acetoacetone; Diacetylmethane; Pentane-2,4-dione; 2-Propanone, acetyl-; 2,4-Dioxopentane; 2,4-Pentadione; CH3COCH2COCH3; Acetone, acetyl-; ACAC; Pentanedione; Pentanedione-2,4; Acetyl 2-propanone; UN 2310; 2,4-Pentandione; Pentan-2,4-dione; NSC 5575
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Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | -384.4 ± 1.3 | kJ/mol | Ccb | Hacking and Pilcher, 1979 | Heat of enolization=-11.3±0.4 kJ/mol |
| ΔfH°gas | -420.1 | kJ/mol | Ion | Conrath, Van de Sande, et al., 1974 | Mass spectrometery (enol) |
| ΔfH°gas | -376.1 ± 2.0 | kJ/mol | Cm | Melia and Merrifield, 1969 | Thermochemical cycle |
Condensed phase thermochemistry data
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°liquid | -427.6 ± 1.1 | kJ/mol | Ccb | Hacking and Pilcher, 1979 | Heat of enolization=-11.3±0.4 kJ/mol |
| ΔfH°liquid | -447.3 ± 8.0 | kJ/mol | Ccb | Vilcu and Perisanu, 1979 | |
| ΔfH°liquid | -414.1 ± 2.0 | kJ/mol | Cm | Melia and Merrifield, 1969 | Thermochemical cycle |
| ΔfH°liquid | -528.94 | kJ/mol | Ccb | Guinchant, 1918 | Author hf288_condensed[kcal/mol]=-131.2 kcal/mol |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°liquid | -2685.4 ± 0.8 | kJ/mol | Ccb | Hacking and Pilcher, 1979 | Heat of enolization=-11.3±0.4 kJ/mol; Corresponding ΔfHºliquid = -425.5 kJ/mol (simple calculation by NIST; no Washburn corrections) |
| ΔcH°liquid | -2667. ± 12. | kJ/mol | Ccb | Vilcu and Perisanu, 1979 | Corresponding ΔfHºliquid = -443.88 kJ/mol (simple calculation by NIST; no Washburn corrections) |
| ΔcH°liquid | -2687.0 ± 1.5 | kJ/mol | Ccb | Nicholson, 1957 | Corresponding ΔfHºliquid = -423.92 kJ/mol (simple calculation by NIST; no Washburn corrections) |
| ΔcH°liquid | -2581.9 | kJ/mol | Ccb | Guinchant, 1918 | Author hf288_condensed[kcal/mol]=-131.2 kcal/mol; Corresponding ΔfHºliquid = -528.98 kJ/mol (simple calculation by NIST; no Washburn corrections) |
Reaction thermochemistry data
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
B - John E. Bartmess
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
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
C5H7O2- + =
By formula: C5H7O2- + H+ = C5H8O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1438. ± 8.8 | kJ/mol | G+TS | Taft and Bordwell, 1988 | gas phase; at 330K: neutral enol/keto ratio should be 8:1 ( Strohmeier and Höhne, 1952); B |
| ΔrH° | 1438. ± 9.6 | kJ/mol | G+TS | Cumming and Kebarle, 1978 | gas phase; At 500K: neutral enol/keto ratio is 1.7:1, Folkendt, Weiss-Lopez, et al., 1989. ΔH=-4.7 kcal/mol, enol favored. Carbonyls anti in anion, via calc: Irikura, 1999; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1409. ± 8.4 | kJ/mol | IMRE | Taft and Bordwell, 1988 | gas phase; at 330K: neutral enol/keto ratio should be 8:1 ( Strohmeier and Höhne, 1952); B |
| ΔrG° | 1408. ± 8.4 | kJ/mol | IMRE | Cumming and Kebarle, 1978 | gas phase; At 500K: neutral enol/keto ratio is 1.7:1, Folkendt, Weiss-Lopez, et al., 1989. ΔH=-4.7 kcal/mol, enol favored. Carbonyls anti in anion, via calc: Irikura, 1999; B |
=
By formula: C5H8O2 = C5H8O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -7.9 ± 0.4 | kJ/mol | Kin | Schweig, Vermeer, et al., 1974 | liquid phase; Photoelectron spectroscopy; ALS |
| ΔrH° | -10. ± 0.8 | kJ/mol | Eqk | Thompson and Allred, 1971 | liquid phase; solvent: Cyclohexane; NMR, UV; ALS |
| ΔrH° | -12. ± 0.8 | kJ/mol | Eqk | Calmon, 1969 | liquid phase; ALS |
+
= (
•
)
By formula: Cl- + C5H8O2 = (Cl- • C5H8O2)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrG° | 56.07 | kJ/mol | TDEq | French, Ikuta, et al., 1982 | gas phase; B |
Free energy of reaction
| ΔrG° (kJ/mol) | T (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 46.0 | 421. | PHPMS | French, Ikuta, et al., 1982 | gas phase; M |
+
= (
•
)
By formula: I- + C5H8O2 = (I- • C5H8O2)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 63.2 ± 4.2 | kJ/mol | TDAs | Caldwell, Masucci, et al., 1989 | gas phase; B,M |
=
By formula: C5H8O2 = C6H10O3
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -19.5 ± 0.75 | kJ/mol | Eqk | Folkendt, Weiss-Lopez, et al., 1985 | gas phase; NMR; ALS |
=
By formula: C5H8O2 = C5H8O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 16.8 | kJ/mol | Eqk | Mines and Thompson, 1975 | gas phase; ALS |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Hacking and Pilcher, 1979
Hacking, J.M.; Pilcher, G.,
Enthalpy of combustion of pentane-2,4-dione,
J. Chem. Thermodyn., 1979, 11, 1015-1017. [all data]
Conrath, Van de Sande, et al., 1974
Conrath, k.; Van de Sande, C.; Vandewalle, M.,
Studies in organic mass spectrometry. XVI. A combined approach to the structures of ions generated from the molecular ions of acyclic β-diketones through loss of small neutral molecules,
Org. Mass Spectrom., 1974, 9, 585-593. [all data]
Melia and Merrifield, 1969
Melia, T.P.; Merrifield, R.,
Thermal properties of acetylacetone,
J. Appl. Chem., 1969, 19, 79-82. [all data]
Vilcu and Perisanu, 1979
Vilcu, R.; Perisanu, S.,
The standard enthalpies of formation of some C, H, O containing compounds,
Rev. Roum. Chim., 1979, 24, 237-243. [all data]
Guinchant, 1918
Guinchant, M.J.,
Etude sur la fonction acide dans les derives metheniques et methiniques,
Ann. Chem., 1918, 10, 30-84. [all data]
Nicholson, 1957
Nicholson, G.R.,
The heat of combustion of acetylacetone,
J. Chem. Soc., 1957, 2431-2432. [all data]
Taft and Bordwell, 1988
Taft, R.W.; Bordwell, F.G.,
Structural and Solvent Effects Evaluated from Acidities Measured in Dimethyl Sulfoxide and in the Gas Phase,
Acc. Chem. Res., 1988, 21, 12, 463, https://doi.org/10.1021/ar00156a005
. [all data]
Strohmeier and Höhne, 1952
Strohmeier, W.; Höhne, I.,
Keto-Enol-Umwandlung des Acetylacteons in Gaszustand,
Z. Naturfor., 1952, 7B, 184. [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]
Folkendt, Weiss-Lopez, et al., 1989
Folkendt, M.M.; Weiss-Lopez, B.E.; Chauvel, J.P., Jr.; True, N.S.,
Gas-Phase 1H NMR Studies of Keto-Enol Tautomerization of Acetylacetone, Methyl Acetoacetate, and Ethyl Acetoacetate,
J. Phys. Chem., 1989, 89, 15, 3347, https://doi.org/10.1021/j100261a038
. [all data]
Irikura, 1999
Irikura, K.K.,
Acetylacetonate (acac) anion in the gas phase: predicted structures, vibrational spectra, and photodetachment energies,
Int. J. Mass Spectrom., 1999, 187, 577-587, https://doi.org/10.1016/S1387-3806(98)14192-1
. [all data]
Schweig, Vermeer, et al., 1974
Schweig, A.; Vermeer, H.; Weidner, U.,
A photoelectron spectroscopic study of keto-enol tautomerism in acetylacetones - a new application of photoelectron spectroscopy,
Chem. Phys. Lett., 1974, 26, 229-233. [all data]
Thompson and Allred, 1971
Thompson, D.W.; Allred, A.L.,
Keto-enol equilibria in 2,4-Pentanedione and 3,3-dideuterio-2,4-pentanedione,
J. Phys. Chem., 1971, 75, 433-435. [all data]
Calmon, 1969
Calmon, J.P.,
Thermodynamic functions of enolization of aliphatic β-diketones,
C. R. Acad. Sci. Paris, 1969, 268, 1435-1438. [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]
Caldwell, Masucci, et al., 1989
Caldwell, G.W.; Masucci, J.A.; Ikonomou, M.G.,
Negative Ion Chemical Ionization Mass Spectrometry - Binding of Molecules to Bromide and Iodide Anions,
Org. Mass Spectrom., 1989, 24, 1, 8, https://doi.org/10.1002/oms.1210240103
. [all data]
Folkendt, Weiss-Lopez, et al., 1985
Folkendt, M.M.; Weiss-Lopez, B.E.; Chauvel, J.P., Jr.; True, N.S.,
Gas-phase 1H NMR studies of keto-enol tautomerism of acetylacetone, methyl acetoacetate, and ethyl acetoacetate,
J. Phys. Chem., 1985, 89, 3347-3352. [all data]
Mines and Thompson, 1975
Mines, G.W.; Thompson, H.,
Infrared and photoelectron spectra, and keto-enol tautomerism of acetylacetones and acetoacetic esters,
Proc. Roy. Soc. London A, 1975, 342, 327-339. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, References
- Symbols used in this document:
T Temperature ΔcH°liquid Enthalpy of combustion of liquid at standard conditions ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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