2-Pentenoic acid
- Formula: C5H8O2
- Molecular weight: 100.1158
- IUPAC Standard InChI: InChI=1S/C5H8O2/c1-2-3-4-5(6)7/h3-4H,2H2,1H3,(H,6,7)
- IUPAC Standard InChIKey: YIYBQIKDCADOSF-UHFFFAOYSA-N
- CAS Registry Number: 626-98-2
- Chemical structure:
This structure is also available as a 2d Mol file - Stereoisomers:
- Other names: C2H5CH=CHCOOH; Pent-2-enoic acid
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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 by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔcH°liquid | -636.80 ± 0.60 | kcal/mol | Ccb | Schjanberg, 1937 | Reanalyzed by Cox and Pilcher, 1970, Original value = -637. ± 2. kcal/mol; At 293 K; Corresponding ΔfHºliquid = -106.72 kcal/mol (simple calculation by NIST; no Washburn corrections) |
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
C5H7O2- + =
By formula: C5H7O2- + H+ = C5H8O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 345.2 ± 2.9 | kcal/mol | G+TS | Graul, Schnute, et al., 1990 | gas phase; Trans isomer |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 338.2 ± 2.8 | kcal/mol | CIDC | Graul, Schnute, et al., 1990 | gas phase; Trans isomer |
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 compiled as indicated in comments:
B - John E. Bartmess
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 10.14 | PE | Holmes, Terlouw, et al., 1979 | LLK |
De-protonation reactions
C5H7O2- + =
By formula: C5H7O2- + H+ = C5H8O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 345.2 ± 2.9 | kcal/mol | G+TS | Graul, Schnute, et al., 1990 | gas phase; Trans isomer; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 338.2 ± 2.8 | kcal/mol | CIDC | Graul, Schnute, et al., 1990 | gas phase; Trans isomer; B |
References
Go To: Top, 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.
Schjanberg, 1937
Schjanberg, E.,
Die verbrennungswarmen und die refraktionsdaten einiger pentensaureeste,
Z. Phys. Chem., 1937, 178, 274-281. [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]
Graul, Schnute, et al., 1990
Graul, S.T.; Schnute, M.E.; Squires, R.R.,
Gas-Phase Acidities of Carboxylic Acids and Alcohols from Collision-Induced Dissociation of Dimer Cluster Ions,
Int. J. Mass Spectrom. Ion Proc., 1990, 96, 2, 181, https://doi.org/10.1016/0168-1176(90)87028-F
. [all data]
Holmes, Terlouw, et al., 1979
Holmes, J.L.; Terlouw, J.K.; Vijfhuizen, P.C.; A'Campo, C.,
Metastable ion studies XII-Molecular and fragment ion structures for isomeric C4H6O2 acids,
Org. Mass Spectrom., 1979, 14, 204. [all data]
Notes
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- Symbols used in this document:
ΔcH°liquid Enthalpy of combustion 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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