Acetylacetone

• Formula: C₅H₈O₂
• Molecular weight: 100.1158
• IUPAC Standard InChI: InChI=1S/C5H8O2/c1-4(6)3-5(2)7/h3H2,1-2H3 Copy

  
• IUPAC Standard InChIKey: YRKCREAYFQTBPV-UHFFFAOYSA-N Copy
• 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
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
  • Ion clustering data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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Gas phase thermochemistry data

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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

Reaction thermochemistry data

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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

=

By formula: C₅H₈O₂ = C₅H₈O₂

 +  = ( • )

By formula: Cl^- + C₅H₈O₂ = (Cl^- • C₅H₈O₂)

Free energy of reaction

 +  = ( • )

By formula: I^- + C₅H₈O₂ = (I^- • C₅H₈O₂)

=

By formula: C₅H₈O₂ = C₆H₁₀O₃

=

By formula: C₅H₈O₂ = C₅H₈O₂

Gas phase ion energetics data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

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

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₅H₇O₂^- +  =

By formula: C₅H₇O₂^- + H⁺ = C₅H₈O₂

References

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

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]

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]

Houk, Davis, et al., 1973
Houk, K.N.; Davis, L.P.; Newkome, G.R.; Duke, R.E., Jr.; Nauman, R.V., Photoelectron spectroscopy of cyclic β-diketones their enolone tautomers, J. Am. Chem. Soc., 1973, 95, 8364. [all data]

Shigorin, Filyugina, et al., 1967
Shigorin, D.N.; Filyugina, A.D.; Potapov, V.K., Role of intramolecular hydrogen bonding in the ionisation and dissociation of compounds, Zh. Fiz. Khim., 1967, 41, 2336, In original 1255. [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]

Hush, Livett, et al., 1987
Hush, N.S.; Livett, M.K.; Peel, J.B.; Willett, G.D., Variable-temperature ultraviolet photoelectron spectroscopy of the keto-enol tautomers of pentane-2,4-dione, Aust. J. Chem., 1987, 40, 599. [all data]

Cauletti, Furlani, et al., 1980
Cauletti, C.; Furlani, C.; Storto, G., Coordinative bond d-shell ionisations in the UV photoelectron spectra of bis({beta}-diketonato) cobalt (II) copper (II) complexes, their thio analogues, J. Electron Spectrosc. Relat. Phenom., 1980, 18, 329. [all data]

Schweig, Vermeer, et al., 1974, 2
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. [all data]

Evans, Hamnett, et al., 1972
Evans, S.; Hamnett, A.; Orchard, A.F.; Lloyd, D.R., Study of the metal-oxygen bond in simple tris-chelate complexes by He(I) photoelectron spectroscopy, Faraday Discuss. Chem. Soc., 1972, 54, 227. [all data]

Reichert and Westmore, 1969
Reichert, C.; Westmore, J.B., Mass spectral studies of metal chelates. IV.Mass spectra, appearance potentials, and coordinate bond energies of bis(acetylacetonate)metal(II) complexes of the first transition series, Inorg. Chem., 1969, 8, 1012. [all data]

Notes

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

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  T	Temperature
  ΔfH°gas	Enthalpy of formation of gas 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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