Propanoic acid, 2-methyl-
- Formula: C4H8O2
- Molecular weight: 88.1051
- IUPAC Standard InChIKey: KQNPFQTWMSNSAP-UHFFFAOYSA-N
- CAS Registry Number: 79-31-2
- 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: Isobutyric acid; α-Methylpropanoic acid; α-Methylpropionic acid; Dimethylacetic acid; Isobutanoic acid; Isopropylformic acid; 2-Methylpropanoic acid; 2-Methylpropionic acid; iso-C3H7COOH; Acetic acid, dimethyl-; Cenex RP b2; Propionic acid, 2-methyl-; Tenox IBP 2; Kyselina isomaselna; UN 2529; Methylpropanoic acid; Methylpropionic acid; 2-Propanecarboxylic acid; i-Butyric acid; NSC 62780
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Gas phase ion energetics data
Go To: Top, Ion clustering data, References, Notes
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:
L - Sharon G. Lias
Data compiled as indicated in comments:
B - John E. Bartmess
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 C4H8O2+ (ion structure unspecified)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 10.24 ± 0.12 | eV | N/A | N/A | L |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
10.12 | EI | Holmes and Lossing, 1980 | LLK |
10.329 ± 0.005 | PI | Watanabe, Yokoyama, et al., 1974 | LLK |
10.33 | PE | Watanabe, Yokoyama, et al., 1973 | LLK |
10.33 ± 0.03 | PE | Thomas, 1972 | LLK |
10.02 ± 0.05 | PI | Watanabe, Nakayama, et al., 1962 | RDSH |
10.30 | PE | Sustmann and Trill, 1972 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
CHO2+ | 11.28 | C3H7 | EI | Holmes, Lossing, et al., 1991 | LL |
De-protonation reactions
By formula: C4H7O2- + H+ = C4H8O2
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 1448. ± 8.8 | kJ/mol | G+TS | Caldwell, Renneboog, et al., 1989 | gas phase; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 1418. ± 8.4 | kJ/mol | IMRE | Caldwell, Renneboog, et al., 1989 | gas phase; B |
Ion clustering data
Go To: Top, Gas phase ion energetics 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
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. Searches may be limited to ion clustering reactions. A general reaction search form is also available.
Clustering reactions
By formula: C4H7O2- + C4H8O2 = (C4H7O2- • C4H8O2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 125. ± 4.2 | kJ/mol | N/A | Meot-Ner and Sieck, 1986 | gas phase; B,M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 140. | J/mol*K | PHPMS | Meot-Ner and Sieck, 1986 | gas phase; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 83.3 ± 6.7 | kJ/mol | TDAs | Meot-Ner and Sieck, 1986 | gas phase; B |
By formula: I- + C4H8O2 = (I- • C4H8O2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 69.9 ± 4.2 | kJ/mol | TDAs | Caldwell and Kebarle, 1984 | gas phase; B,M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 85.8 | J/mol*K | PHPMS | Caldwell and Kebarle, 1984 | gas phase; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 44.4 ± 4.2 | kJ/mol | TDAs | Caldwell and Kebarle, 1984 | gas phase; B |
References
Go To: Top, Gas phase ion energetics data, Ion clustering data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Holmes and Lossing, 1980
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]
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]
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]
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]
Sustmann and Trill, 1972
Sustmann, R.; Trill, H.,
Photoelektronenspektroskopische Bestimmung von Substituenten-Effekten. II. α,β-ungesattigte Carbonester,
Tetrahedron Lett., 1972, 42, 4271. [all data]
Holmes, Lossing, et al., 1991
Holmes, J.L.; Lossing, F.P.; Mayer, P.M.,
Heats of formation of oxygen-containing organic free radicals from appearance energy measurements,
J. Am. Chem. Soc., 1991, 113, 9723. [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]
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]
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]
Notes
Go To: Top, Gas phase ion energetics data, Ion clustering data, References
- Symbols used in this document:
AE Appearance energy IE (evaluated) Recommended ionization energy ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔrS° Entropy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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