MeCOCH=C(Me)O anion
- Formula: C5H7O2-
- Molecular weight: 99.1084
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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 by: John E. Bartmess
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Individual Reactions
C5H7O2- + =
By formula: C5H7O2- + H+ = C5H8O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 343.8 ± 2.1 | kcal/mol | G+TS | Taft and Bordwell, 1988 | gas phase; at 330K: neutral enol/keto ratio should be 8:1 ( Strohmeier and Höhne, 1952) |
| ΔrH° | 343.7 ± 2.3 | kcal/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 |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 336.7 ± 2.0 | kcal/mol | IMRE | Taft and Bordwell, 1988 | gas phase; at 330K: neutral enol/keto ratio should be 8:1 ( Strohmeier and Höhne, 1952) |
| ΔrG° | 336.6 ± 2.0 | kcal/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 |
References
Go To: Top, Reaction thermochemistry data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
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]
Notes
Go To: Top, Reaction thermochemistry data, References
- Symbols used in this document:
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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