Acetic acid, methyl ester

Formula: C₃H₆O₂
Molecular weight: 74.0785
IUPAC Standard InChI: InChI=1S/C3H6O2/c1-3(4)5-2/h1-2H3
IUPAC Standard InChIKey: KXKVLQRXCPHEJC-UHFFFAOYSA-N
CAS Registry Number: 79-20-9
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: Methyl acetate; Devoton; Tereton; CH3COOCH3; Methyl ethanoate; Acetate de methyle; Methyl acetic ester; Methylacetaat; Methylacetat; Methyle (acetate de); Methylester kiseliny octove; Metile (acetato di); Ethyl ester of monoacetic acid; UN 1231; Methyl ester of acetic acid; NSC 405071
Permanent link for this species. Use this link for bookmarking this species for future reference.
Information on this page:
Other data available:
Data at other public NIST sites:
- Gas Phase Kinetics Database
Options:
- Switch to calorie-based units

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Gas phase ion energetics data

Go To: Top, Vibrational and/or electronic energy levels, References, Notes

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C₃H₆O₂⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	10.25 ± 0.02	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	821.6	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	790.7	kJ/mol	N/A	Hunter and Lias, 1998	HL

Ionization energy determinations

IE (eV)	Method	Reference	Comment
10.2	PE	Cannington and Ham, 1985	LBLHLM
10.25	PI	Traeger, McLouglin, et al., 1982	LBLHLM
10.25 ± 0.05	PE	Benoit, Harrison, et al., 1977	LLK
10.33	PE	Sweigart and Turner, 1972	LLK
10.27 ± 0.02	PI	Watanabe, Nakayama, et al., 1962	RDSH
10.5	PE	Cannington and Ham, 1985	Vertical value; LBLHLM
10.25	PE	Benoit and Harrison, 1977	Vertical value; LLK
11.0	PE	Rao, 1975	Vertical value; LLK
10.59	PE	Sustmann and Trill, 1972	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
CHO⁺	13.95 ± 0.08	?	EI	Brion and Dunning, 1963	RDSH
CH₂⁺	20.8	?	EI	King and Long, 1958	RDSH
CH₃⁺	13.07 ± 0.10	?	EI	Brion and Dunning, 1963	RDSH
CH₃O⁺	12.52 ± 0.10	?	EI	Brion and Dunning, 1963	RDSH
C₂H₂O⁺	11.81 ± 0.15	?	EI	Friedland and Strakna, 1956	RDSH
C₂H₃O⁺	11.05	CH₃O	PI	Traeger, McLouglin, et al., 1982	LBLHLM
C₂H₃O⁺	10.9 ± 0.1	CH₃O	EI	Burgers and Holmes, 1982	LBLHLM
C₂H₃O⁺	10.94	?	EI	Holmes and Lossing, 1979	LLK
C₂H₃O⁺	11.37 ± 0.05	CH₃O	EI	Haney and Franklin, 1969	RDSH
C₂H₃O₂⁺	11.32 ± 0.05	CH₃	EI	Blanchette, Holmes, et al., 1986	LBLHLM
C₂H₃O₂⁺	12.35 ± 0.03	CH₃	EI	Briggs and Shannon, 1969	RDSH

De-protonation reactions

C₃H₅O₂^- + = Acetic acid, methyl ester

By formula: C₃H₅O₂^- + H⁺ = C₃H₆O₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1556. ± 8.8	kJ/mol	G+TS	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B
Δ_rH°	1556. ± 15.	kJ/mol	D-EA	Zimmerman, Reed, et al., 1977	gas phase; B
Δ_rH°	1573. ± 15.	kJ/mol	EIAE	Pariat and Allan, 1991	gas phase; From CH3CO2Me; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1528. ± 8.4	kJ/mol	IMRE	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B

Vibrational and/or electronic energy levels

Go To: Top, Gas phase ion energetics data, References, Notes

Data compiled by: Takehiko Shimanouchi

Symmetry: C_s Symmetry Number σ = 1

Sym.	No	Approximate	Selected Freq.		Infrared		Raman		Comments

Species		type of mode	Value	Rating	Value	Phase	Value	Phase

a'	1	CH3(O) d-str	3035	D	3035 M	gas	3028	liq.
a'	2	CH3(C) d-str	3031	E					SF(ν₂ )of 3OCD3
a'	3	CH3(O) s-str	2966	D	2966 S	gas	2954 p	liq.
a'	4	CH3(C) s-str	2964	E			2942 p	liq.	SF(ν₄ )of 3OCD3
a'	5	C=O str	1771	C	1771 VS	gas	1738 p	liq.
a'	6	CH3(O) d-deform	1460	E	1460 W sh	solid solid			OV(ν₂₀)
a'	7	CH3(O) s-deform	1440	D	1440 M	gas
a'	8	CH3(C) d-deform	1430	E					SF(ν₈ )of 3OCD3
a'	9	CH3(C) s-deform	1375	D	1375 S	gas	1372 p	liq.
a'	10	C-O str	1248	C	1248 VS	gas	1254	liq.
a'	11	CH3(O) rock	1159	E	1159 VW	liq.
a'	12	O-CH3 str	1060	C	1060 S	gas	1044	liq.
a'	13	CH3(C) rock	980	C	980 W	gas	980 p	liq.
a'	14	CC str	844	C	844 M	gas	844 p	liq.
a'	15	C=O ip-bend	639	C	639 M	gas	640 p	liq.
a'	16	CCO deform	429	C	429 M	gas	433 p	liq.
a	17	COC deform	303	D	303 M	gas	303 p	liq.
a	18	CH3(O) d-str	3005	D	3005 M	gas	3002	liq.
a	19	CH3(C) d-str	2994	D	2994 W	gas
a	20	CH3(O) d-deform	1460	E	1460 W sh	solid solid	1449 dp	liq.	OV(ν₆)
a	21	CH3(C) d-deform	1430	E	1430 W	gas
a	22	CH3(O) rock	1187	D	1187 W	gas	1187	liq.
a	23	CH3(C) rock	1036	E	1036 W	sln.
a	24	C=O op-bend	607	D	607 M	gas	610 dp	liq.
a	25	C-O torsion	187	D	187 W	gas
a	26	C-C torsion	136	E	136 VW	liq.
a	27	O-CH3 torsion	110	E	110 VW	liq.

Source: Shimanouchi, 1972

Notes

Very strong

Strong

Medium

Weak

Very weak

Shoulder

Polarized

Depolarized

Frequency estimated from an overtone or a combination tone indicated in the parentheses.

Calculation shows that the frequency approximately equals that of the vibration indicated in the parentheses.

Overlapped by band indicated in parentheses.

3~6 cm^-1 uncertainty

6~15 cm^-1 uncertainty

15~30 cm^-1 uncertainty

References

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, Notes

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]

Cannington and Ham, 1985
Cannington, P.H.; Ham, N.S., He(II) photoelectron spectra of esters, J. Electron Spectrosc. Relat. Phenom., 1985, 36, 203. [all data]

Traeger, McLouglin, et al., 1982
Traeger, J.C.; McLouglin, R.G.; Nicholson, A.J.C., Heat of formation for acetyl cation in the gas phase, J. Am. Chem. Soc., 1982, 104, 5318. [all data]

Benoit, Harrison, et al., 1977
Benoit, F.M.; Harrison, A.G.; Lossing, F.P., Hydrogen migrations in mass spectrometry III-Energetics of formation of [R'CO₂H₂]⁺ in the mass spectra of R'CO₂R, Org. Mass Spectrom., 1977, 12, 78. [all data]

Sweigart and Turner, 1972
Sweigart, D.A.; Turner, D.W., Lone pair orbitals and their interactions studied by photoelectron spectroscopy. I. Carboxylic acids and their derivatives, J. Am. Chem. Soc., 1972, 94, 5592. [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]

Benoit and Harrison, 1977
Benoit, F.M.; Harrison, A.G., Predictive value of proton affinity. Ionization energy correlations involving oxygenated molecules, J. Am. Chem. Soc., 1977, 99, 3980. [all data]

Rao, 1975
Rao, C.N.R., Lone-pair ionization bands of chromophores in the photoelectron spectra of organic molecules, Indian J. Chem., 1975, 13, 950. [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]

Brion and Dunning, 1963
Brion, C.E.; Dunning, W.J., Electron impact studies of simple carboxylic esters, J. Chem. Soc. Faraday Trans., 1963, 59, 647. [all data]

King and Long, 1958
King, A.B.; Long, F.A., Mass spectra of some simple esters and their interpretation by quasi-equilibrium theory, J. Chem. Phys., 1958, 29, 374. [all data]

Friedland and Strakna, 1956
Friedland, S.S.; Strakna, R.E., Appearance potential studies. I, J. Phys. Chem., 1956, 60, 815. [all data]

Burgers and Holmes, 1982
Burgers, P.C.; Holmes, J.L., Metastable ion studies. XIII. The measurement of appearance energies of metastable peaks, Org. Mass Spectrom., 1982, 17, 123. [all data]

Holmes and Lossing, 1979
Holmes, J.L.; Lossing, F.P., Keto and enol forms of methyl acetate molecular ions, their stability and interconvertibility prior to fragmentation in the gas phase, Org. Mass Spectrom., 1979, 14, 512. [all data]

Haney and Franklin, 1969
Haney, M.A.; Franklin, J.L., Excess energies in mass spectra of some oxygen-containing organic compounds, J. Chem. Soc. Faraday Trans., 1969, 65, 1794. [all data]

Blanchette, Holmes, et al., 1986
Blanchette, M.C.; Holmes, J.L.; Hop, C.E.C.A.; Lossing, F.P.; Postma, R.; Ruttink, P.J.A.; Terlouw, J.K., Theory and experiment in concert; the CH₃O-C=O⁺ ion and its isomers, J. Am. Chem. Soc., 1986, 108, 7589. [all data]

Briggs and Shannon, 1969
Briggs, P.R.; Shannon, T.W., The heat of formation of the methoxycarbonyl ion, J. Am. Chem. Soc., 1969, 91, 4307. [all data]

Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr., The gas phase acidity scale from methanol to phenol, J. Am. Chem. Soc., 1979, 101, 6047. [all data]

Zimmerman, Reed, et al., 1977
Zimmerman, A.H.; Reed, K.J.; Brauman, J.I., Photodetachment of electrons from enolate anions. Gas phase electron affinities of enolate radicals, J. Am. Chem. Soc., 1977, 99, 7203. [all data]

Pariat and Allan, 1991
Pariat, Y.; Allan, M., Dissociative Attachment to Methyl Acetate: Evidence for Ion/Molecule Complexes as Intermediates, Int. J. Mass Spectrom. Ion Proc., 1991, 103, 2-3, 181, https://doi.org/10.1016/0168-1176(91)80088-5 . [all data]

Shimanouchi, 1972
Shimanouchi, T., Tables of Molecular Vibrational Frequencies Consolidated Volume I, National Bureau of Standards, 1972, 1-160. [all data]

Notes

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References

Symbols used in this document:

AE Appearance energy

IE (evaluated) Recommended ionization energy

Δ_rG° Free energy of reaction at standard conditions

Δ_rH° Enthalpy of reaction at standard conditions
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
Customer support for NIST Standard Reference Data products.

AE	Appearance energy
IE (evaluated)	Recommended ionization energy
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions

Acetic acid, methyl ester

Data at NIST subscription sites:

Gas phase ion energetics data

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

Vibrational and/or electronic energy levels

Symmetry: Cs Symmetry Number σ = 1

Notes

References

Notes

Symmetry: C_s Symmetry Number σ = 1