Methacrolein
- Formula: C4H6O
- Molecular weight: 70.0898
- IUPAC Standard InChI: InChI=1S/C4H6O/c1-4(2)3-5/h3H,1H2,2H3
- IUPAC Standard InChIKey: STNJBCKSHOAVAJ-UHFFFAOYSA-N
- CAS Registry Number: 78-85-3
- Chemical structure:
This structure is also available as a 2d Mol file - Other names: 2-Propenal, 2-methyl-; Methacrylaldehyde; α-Methylacrolein; Isobutenal; Methacrylic aldehyde; Methylacrylaldehyde; 2-Methylacrolein; 2-Methylpropenal; CH2=C(CH3)CHO; 2-Methylenepropanal; 2-Methylprop-2-enal; α-Methacrolein; Acrolein, 2-methyl-; Methacraldehyde; Methakrylaldehyd; 2-Methyl-2-propenal; NSC 8260; Methylacroleine
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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
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | -106.4 ± 2.0 | kJ/mol | Ccb | Van-chin-syan, Kochubei, et al., 1996 |
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 |
|---|---|---|---|---|---|
| ΔfH°liquid | -138.6 ± 2.0 | kJ/mol | Ccb | Van-chin-syan, Kochubei, et al., 1996 | |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔcH°liquid | -2293.0 ± 1.9 | kJ/mol | Ccb | Van-chin-syan, Kochubei, et al., 1996 | Corresponding ΔfHºliquid = -138.5 kJ/mol (simple calculation by NIST; no Washburn corrections) |
Phase change 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:
BS - Robert L. Brown and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Tboil | 341.6 | K | N/A | Weast and Grasselli, 1989 | BS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔvapH° | 32.2 | kJ/mol | N/A | Van-chin-syan, Kochubei, et al., 1996 | DRB |
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
C4H5O- + =
By formula: C4H5O- + H+ = C4H6O
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1576. ± 13. | kJ/mol | G+TS | Kleingeld and Nibbering, 1984 | gas phase; Acid: 2-methylpropenal. Reprotonation to dimethyl ketene? G3MP2B3 calculations indicate a dHacid of 396 kcal/mol |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1544. ± 13. | kJ/mol | IMRB | Kleingeld and Nibbering, 1984 | gas phase; Acid: 2-methylpropenal. Reprotonation to dimethyl ketene? G3MP2B3 calculations indicate a dHacid of 396 kcal/mol |
C4H5O- + =
By formula: C4H5O- + H+ = C4H6O
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1578. ± 13. | kJ/mol | G+TS | Bartmess and Burnham, 1984 | gas phase; value altered from reference due to change in acidity scale |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1549. ± 13. | kJ/mol | IMRB | Bartmess and Burnham, 1984 | gas phase; value altered from reference due to change in acidity scale |
| ΔrG° | 1544. ± 13. | kJ/mol | IMRB | Kleingeld and Nibbering, 1984 | gas phase |
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
Data compiled as indicated in comments:
B - John E. Bartmess
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
View reactions leading to C4H6O+ (ion structure unspecified)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Proton affinity (review) | 808.7 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
| Quantity | Value | Units | Method | Reference | Comment |
| Gas basicity | 776.8 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 9.92 | PE | Masclet and Mouvier, 1978 | LLK |
De-protonation reactions
C4H5O- + =
By formula: C4H5O- + H+ = C4H6O
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1576. ± 13. | kJ/mol | G+TS | Kleingeld and Nibbering, 1984 | gas phase; Acid: 2-methylpropenal. Reprotonation to dimethyl ketene? G3MP2B3 calculations indicate a dHacid of 396 kcal/mol; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1544. ± 13. | kJ/mol | IMRB | Kleingeld and Nibbering, 1984 | gas phase; Acid: 2-methylpropenal. Reprotonation to dimethyl ketene? G3MP2B3 calculations indicate a dHacid of 396 kcal/mol; B |
C4H5O- + =
By formula: C4H5O- + H+ = C4H6O
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1578. ± 13. | kJ/mol | G+TS | Bartmess and Burnham, 1984 | gas phase; value altered from reference due to change in acidity scale; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1549. ± 13. | kJ/mol | IMRB | Bartmess and Burnham, 1984 | gas phase; value altered from reference due to change in acidity scale; B |
| ΔrG° | 1544. ± 13. | kJ/mol | IMRB | Kleingeld and Nibbering, 1984 | gas phase; B |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change 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.
Van-chin-syan, Kochubei, et al., 1996
Van-chin-syan, Yu.Ya.; Kochubei, V.V.; Sergeev, V.V.; Raevskii, Yu.A.; Gerasimchuk, S.I.; Kotovich, Kh.Z.,
Thermodynamic properties of some acids and aldehydes of the acrylic series,
Sov. J. Chem. Phys. (Engl. Transl.), 1996, 70, 1789-1794, In original 1932. [all data]
Weast and Grasselli, 1989
CRC Handbook of Data on Organic Compounds, 2nd Editon, Weast,R.C and Grasselli, J.G., ed(s)., CRC Press, Inc., Boca Raton, FL, 1989, 1. [all data]
Kleingeld and Nibbering, 1984
Kleingeld, J.C.; Nibbering, N.M.M.,
Negative Ion/Molecule Cycloaddition Reactions of 2-Methylpropenal in the Gas Phase,
Recl. Trav. Chim. Pays-Bas, 1984, 103, 3, 87, https://doi.org/10.1002/recl.19841030303
. [all data]
Bartmess and Burnham, 1984
Bartmess, J.E.; Burnham, R.,
Effect of central substituents on the gas phase acidities of propenes,
J. Org. Chem., 1984, 49, 1382. [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]
Masclet and Mouvier, 1978
Masclet, P.; Mouvier, G.,
Etude par spectrometrie photoelectronique d'aldehydes et de cetones ethyleniques conjugues,
J. Electron Spectrosc. Relat. Phenom., 1978, 14, 77. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
Tboil Boiling point 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 ΔvapH° Enthalpy of vaporization at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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