1-Propene, 2-methyl-

• Formula: C₄H₈
• Molecular weight: 56.1063
• IUPAC Standard InChI: InChI=1S/C4H8/c1-4(2)3/h1H2,2-3H3 Copy

  
• IUPAC Standard InChIKey: VQTUBCCKSQIDNK-UHFFFAOYSA-N Copy
• CAS Registry Number: 115-11-7
• 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: Propene, 2-methyl-; γ-Butylene; Isobutene; Isobutylene; Isopropylidenemethylene; 1,1-Dimethylethylene; 2-Methyl-1-propene; 2-Methylpropene; iso-C4H8; Methylpropene; UN 1055; 1,1-Dimethylethene; 2-Methylpropylene
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase ion energetics data
  • Ion clustering data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Henry's Law data
  • IR Spectrum
  • UV/Visible spectrum
  • Vibrational and/or electronic energy levels
  • Gas Chromatography
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Electron-Impact Ionization Cross Sections (on physics web site)
  • Gas Phase Kinetics Database
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Gas phase ion energetics data

Go To: Top, Ion clustering data, Mass spectrum (electron ionization), References, Notes

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
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
MM - Michael M. Meot-Ner (Mautner)
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 C₄H₈⁺ (ion structure unspecified)

Proton affinity at 298K

Gas basicity at 298K

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₄H₇^- +  =

By formula: C₄H₇^- + H⁺ = C₄H₈

Ion clustering data

Go To: Top, Gas phase ion energetics data, Mass spectrum (electron ionization), 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:
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
RCD - Robert C. Dunbar

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

C₃H₉Si⁺ +  = (C₃H₉Si⁺ • )

By formula: C₃H₉Si⁺ + C₄H₈ = (C₃H₉Si⁺ • C₄H₈)

 +  = ( • )

By formula: H₄N⁺ + C₄H₈ = (H₄N⁺ • C₄H₈)

 +  = ( • )

By formula: Li⁺ + C₄H₈ = (Li⁺ • C₄H₈)

 +  = ( • )

By formula: Na⁺ + C₄H₈ = (Na⁺ • C₄H₈)

Free energy of reaction

Mass spectrum (electron ionization)

Go To: Top, Gas phase ion energetics data, Ion clustering 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: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

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Additional Data

References

Go To: Top, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

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]

Bouchoux and Salpin, 1999
Bouchoux, J.; Salpin, J.Y., Re-evaluated gas-phase basicity and proton affinity data from the thermokinetic method, Rapid Com. Mass Spectrom., 1999, 13, 932. [all data]

Cleven, Hoke, et al., 1996
Cleven, C.D.; Hoke, S.H.; Cooks, R.G.; Hrovat, D.A.; Smith, J.M.; Lee, M.S.; Borden, W.T., Effect of Olefin Pyramidalization on the Proton Affinity of Tricyclo[3.3.3.03,7]undec-3(7)-ene as Determined by ab Initio Calculations and Kinetic Method Measurements, J. Am. Chem. Soc., 1996, 118, 10872. [all data]

Traeger, 1986
Traeger, J.C., Heat of formation for the 1-methylallyl cation by photoionization mass spectrometry, J. Phys. Chem., 1986, 90, 4114. [all data]

Holmes and Lossing, 1983
Holmes, J.L.; Lossing, F.P., The need for adequate thermochemical data for the interpretation of fragmentation mechanisms and ion structure assignments, Int. J. Mass Spectrom. Ion Phys., 1983, 47, 133. [all data]

Bieri, Burger, et al., 1977
Bieri, G.; Burger, F.; Heilbronner, E.; Maier, J.P., Valence ionization enrgies of hydrocarbons, Helv. Chim. Acta, 1977, 60, 2213. [all data]

Masclet, Grosjean, et al., 1973
Masclet, P.; Grosjean, D.; Mouvier, G., Alkene ionization potentials. Part I. Quantitative determination of alkyl group structural effects, J. Electron Spectrosc. Relat. Phenom., 1973, 2, 225. [all data]

Lossing, 1972
Lossing, F.P., Free radicals by mass spectrometry. XLV. Ionization potentials and heats of formation of C₃H₃, C₃H₅, and C₄H₇ radicals and ions, Can. J. Chem., 1972, 50, 3973. [all data]

Frost and Sandhu, 1971
Frost, D.C.; Sandhu, J.S., Ionization potentials of ethylene and some methyl-substituted ethylenes as determined by photoelectron spectroscopy, Indian J. Chem., 1971, 9, 1105. [all data]

Dewar and Worley, 1969
Dewar, M.J.S.; Worley, S.D., Photoelectron spectra of molecules. I. Ionization potentials of some organic molecules and their interpretation, J. Chem. Phys., 1969, 50, 654. [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]

Bralsford, Harris, et al., 1960
Bralsford, R.; Harris, P.V.; Price, W.C., The effect of fluorine on the electronic spectra and ionization potentials of molecules, Proc. Roy. Soc. (London), 1960, A258, 459. [all data]

Wiberg, Ellison, et al., 1976
Wiberg, K.B.; Ellison, G.B.; Wendoloski, J.J.; Brundle, C.R.; Kuebler, N.A., Electronic states of organic molecules. 3. Photoelectron spectra of cycloalkenes and methylenecycloalkanes, J. Am. Chem. Soc., 1976, 98, 7179. [all data]

Koenig, Balle, et al., 1975
Koenig, T.; Balle, T.; Snell, W., Helium(I) photoelectron spectra of organic radicals, J. Am. Chem. Soc., 1975, 97, 662. [all data]

Kimura, Katsumata, et al., 1975
Kimura, K.; Katsumata, S.; Yamazaki, T.; Wakabayashi, H., UV photoelectron spectra and sum rule consideration; out-of-plane orbitals of unsaturated compounds with planar-skeleton structure, J. Electron Spectrosc. Relat. Phenom., 1975, 6, 41. [all data]

SenSharma and Franklin, 1973
SenSharma, D.K.; Franklin, J.L., Heat of formation of free radicals by mass spectrometry, J. Am. Chem. Soc., 1973, 95, 6562. [all data]

Meisels, Park, et al., 1970
Meisels, G.G.; Park, J.Y.; Giessner, B.G., Ionization and dissociation of C₄H₈ isomers, J. Am. Chem. Soc., 1970, 92, 254. [all data]

Traeger, 1984
Traeger, J.C., A study of the allyl cation thermochemistry by photoionization mass spectrometry, Int. J. Mass Spectrom. Ion Processes, 1984, 58, 259. [all data]

Holmes, Weese, et al., 1977
Holmes, J.L.; Weese, G.M.; Blair, A.S.; Terlouw, J.K., Metastable ion studies IX-Thermochemistry and ion structures among fragmenting [C₄H₈]⁺ ions, an electron impact and field ionization investigation, Org. Mass Spectrom., 1977, 12, 424. [all data]

Wenthold, Hu, et al., 1999
Wenthold, P.G.; Hu, J.; Squires, R.R.; Lineberger, W.C., Photoelectron spectroscopy of the trimethylenemethane negative ion, J. Am. Soc. Mass Spectrom., 1999, 10, 9, 800-809, https://doi.org/10.1016/S1044-0305(99)00043-4 . [all data]

Wenthold, Polak, et al., 1996
Wenthold, P.G.; Polak, M.L.; Lineberger, W.C., Photoelectron Spectroscopy of the Allyl and 2-Methylallyl Anions, J. Phys. Chem., 1996, 100, 17, 6920, https://doi.org/10.1021/jp953401n . [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]

Li and Stone, 1989
Li, X.; Stone, J.A., Determination of the beta silicon effect from a mass spectrometric study of the association of trimethylsilylium ion with alkenes, J. Am. Chem. Soc., 1989, 111, 15, 5586, https://doi.org/10.1021/ja00197a013 . [all data]

Meot-Ner (Mautner) and Sieck, 1991
Meot-Ner (Mautner), M.; Sieck, L.W., Proton affinity ladders from variable-temperature equilibrium measurements. 1. A reevaluation of the upper proton affinity range, J. Am. Chem. Soc., 1991, 113, 12, 4448, https://doi.org/10.1021/ja00012a012 . [all data]

Meot-Ner (Mautner) and Sieck, 1990
Meot-Ner (Mautner), M.; Sieck, L.W., Ion Thermochemistry at High Temperatures. 1. Thermochemistry of the Ammonium Ion from Variable - Temperature Equilibrium Measurements. Proton Transfer, Association, and Decomposition Reactions in Ammonia, Isobutene, and t-Butylamine, J. Phys. Chem., 1990, 94, 19, 7730, https://doi.org/10.1021/j100382a076 . [all data]

Staley and Beauchamp, 1975
Staley, R.H.; Beauchamp, J.L., Intrinsic Acid - Base Properties of Molecules. Binding Energies of Li+ to pi - and n - Donor Bases, J. Am. Chem. Soc., 1975, 97, 20, 5920, https://doi.org/10.1021/ja00853a050 . [all data]

Dzidic and Kebarle, 1970
Dzidic, I.; Kebarle, P., Hydration of the Alkali Ions in the Gas Phase. Enthalpies and Entropies of Reactions M+(H2O)n-1 + H2O = M+(H2O)n, J. Phys. Chem., 1970, 74, 7, 1466, https://doi.org/10.1021/j100702a013 . [all data]

McMahon and Ohanessian, 2000
McMahon, T.B.; Ohanessian, G., An Experimental and Ab Initio Study of the Nature of the Binding in Gas-Phase Complexes of Sodium Ions, Chem. Eur. J., 2000, 6, 16, 2931, https://doi.org/10.1002/1521-3765(20000818)6:16<2931::AID-CHEM2931>3.0.CO;2-7 . [all data]

Notes

Go To: Top, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  T	Temperature
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔrS°	Entropy of reaction at standard conditions

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