Propanoic acid, 2-methyl-

• Formula: C₄H₈O₂
• Molecular weight: 88.1051
• IUPAC Standard InChI: InChI=1S/C4H8O2/c1-3(2)4(5)6/h3H,1-2H3,(H,5,6) Copy

  
• IUPAC Standard InChIKey: KQNPFQTWMSNSAP-UHFFFAOYSA-N Copy
• 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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• Information on this page:
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Henry's Law data
  • Ion clustering data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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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:
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)

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

 +  =

By formula: C₄H₇O₂^- + H⁺ = C₄H₈O₂

References

Go To: Top, 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.

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]

Notes

Go To: Top, Gas phase ion energetics 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

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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