Butanoic acid, 3-methyl-
- Formula: C5H10O2
- Molecular weight: 102.1317
- IUPAC Standard InChI: InChI=1S/C5H10O2/c1-4(2)3-5(6)7/h4H,3H2,1-2H3,(H,6,7)
- IUPAC Standard InChIKey: GWYFCOCPABKNJV-UHFFFAOYSA-N
- CAS Registry Number: 503-74-2
- 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: Isovaleric acid; β-Methylbutyric acid; Acetic acid, isopropyl-; Delphinic acid; Isopentanoic acid; Isopropylacetic acid; 3-Methylbutanoic acid; 3-Methylbutyric acid; iso-C4H9COOH; Butyric acid, 3-methyl-; Isovalerianic acid; Kyselina isovalerova; 3-Methyl-n-butyric acid; NSC 62783; Isobutylformic acid; 3-methylbutanoic acid (isovaleric acid); Methylbutanoic acid
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Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry data, 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 by: Donald R. Burgess, Jr.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | -120.1 ± 1.6 | kcal/mol | N/A | Hancock, Watson, et al., 1954 | Value computed using ΔfHliquid° value of -561.6±5.9 kj/mol from Hancock, Watson, et al., 1954 and ΔvapH° value of 59.1±3 kj/mol from sec-alkanoic correlation. |
Condensed 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 as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°liquid | -134.2 ± 1.4 | kcal/mol | Ccb | Hancock, Watson, et al., 1954 | Reanalyzed by Cox and Pilcher, 1970, Original value = -134. kcal/mol; ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°liquid | -677.6 ± 1.4 | kcal/mol | Ccb | Hancock, Watson, et al., 1954 | Reanalyzed by Cox and Pilcher, 1970, Original value = -678. kcal/mol; Corresponding ΔfHºliquid = -134.23 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS |
Constant pressure heat capacity of liquid
| Cp,liquid (cal/mol*K) | Temperature (K) | Reference | Comment |
|---|---|---|---|
| 47.11 | 298. | von Reis, 1881 | T = 290 to 470 K.; DH |
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
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
C5H9O2- + =
By formula: C5H9O2- + H+ = C5H10O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 345.5 ± 2.1 | kcal/mol | G+TS | Caldwell, Renneboog, et al., 1989 | gas phase |
| ΔrH° | 346.7 ± 2.1 | kcal/mol | G+TS | Taft and Topsom, 1987 | gas phase |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 338.5 ± 2.0 | kcal/mol | IMRE | Caldwell, Renneboog, et al., 1989 | gas phase |
| ΔrG° | 339.7 ± 2.0 | kcal/mol | IMRE | Taft and Topsom, 1987 | gas phase |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, 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 as indicated in comments:
B - John E. Bartmess
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 10.51 | PE | Watanabe, Yokoyama, et al., 1973 | Vertical value; LLK |
Appearance energy determinations
| Ion | AE (eV) | Other Products | Method | Reference | Comment |
|---|---|---|---|---|---|
| C2H4O2+ | 10.8 ± 0.1 | C3H6 | EI | Audier, Milliet, et al., 1985 | LBLHLM |
| C2H5O2+ | 10.4 ± 0.1 | C3H5 | EI | Audier, Milliet, et al., 1985 | LBLHLM |
De-protonation reactions
C5H9O2- + =
By formula: C5H9O2- + H+ = C5H10O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 345.5 ± 2.1 | kcal/mol | G+TS | Caldwell, Renneboog, et al., 1989 | gas phase; B |
| ΔrH° | 346.7 ± 2.1 | kcal/mol | G+TS | Taft and Topsom, 1987 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 338.5 ± 2.0 | kcal/mol | IMRE | Caldwell, Renneboog, et al., 1989 | gas phase; B |
| ΔrG° | 339.7 ± 2.0 | kcal/mol | IMRE | Taft and Topsom, 1987 | gas phase; B |
References
Go To: Top, Gas phase thermochemistry data, Condensed 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.
Hancock, Watson, et al., 1954
Hancock, C.K.; Watson, G.M.; Gilby, R.F.,
Heats of combustion of five-carbon fatty acids and their methyl and ethyl esters,
J. Phys. Chem., 1954, 58, 127-129. [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]
von Reis, 1881
von Reis, M.A.,
Die specifische Wärme flüssiger organischer Verbindungen und ihre Beziehung zu deren Moleculargewicht,
Ann. Physik [3], 1881, 13, 447-464. [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]
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]
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]
Audier, Milliet, et al., 1985
Audier, H.; Milliet, A.; Sozzi, G.,
Isomerisation des cation radicaux acides pentanoique et methyl-3-butanoique in phase gazeuse,
Bull. Soc. Chim. France, 1985, 5, 833. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy Cp,liquid Constant pressure heat capacity of liquid 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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