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:
  • Phase change data
  • Gas phase ion energetics data
  • Ion clustering data
  • Vibrational and/or electronic energy levels
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data
  • Henry's Law data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Electron-Impact Ionization Cross Sections (on physics web site)
  • Computational Chemistry Comparison and Benchmark Database
  • Gas Phase Kinetics Database
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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:
DH - Eugene S. Domalski and Elizabeth D. Hearing
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos

Enthalpy of vaporization

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (bar)
    T = temperature (K)

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Enthalpy of fusion

Entropy of fusion

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
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

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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:
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

Vibrational and/or electronic energy levels

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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: Takehiko Shimanouchi

Symmetry:   C_2ν     Symmetry Number σ = 2

Source: Shimanouchi, 1972

Notes

References

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

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

Rabinovich and Lebedev, 1971
Rabinovich, I.B.; Lebedev, B.V., On the thermodynamic stability of polyisobutylene. Tr. Khim. Khim. Tekhnol., 1971, 194-196. [all data]

Kistiakowsky, Ruhoff, et al., 1935
Kistiakowsky, G.B.; Ruhoff, J.R.; Smith, H.A.; Vaughan, W.E., Heats of Organic Reactions II. Hydrogenation of Some Simpler Olefinic Hydrocarbons, J. Am. Chem. Soc., 1935, 57, 876-82. [all data]

Coffin and Maass, 1928
Coffin, C.C.; Maass, O., The Preparation and Physical Properties of α-,β- and γ-Butylene and Normal and Isobutane, J. Am. Chem. Soc., 1928, 50, 1427-37. [all data]

Todd and Parks, 1936
Todd, S.S.; Parks, G.S., Thermal Data on Organic Compounds XV. Some Heat Capacity, Entropy and Free Energy Data for the Isomeric Butenes, J. Am. Chem. Soc., 1936, 58, 134. [all data]

Tsonopoulos and Ambrose, 1996
Tsonopoulos, C.; Ambrose, D., Vapor-Liquid Critical Properties of Elements and Compounds. 6. Unsaturated Aliphatic Hydrocarbons, J. Chem. Eng. Data, 1996, 41, 645-656. [all data]

Beattie, Ingersoll, et al., 1942
Beattie, J.A.; Ingersoll, H.G.; Stockmayer, W.H., Vapor Pressure and Critical Consants of Isobutene, J. Am. Chem. Soc., 1942, 64, 546. [all data]

Reid, 1972
Reid, Robert C., Handbook on vapor pressure and heats of vaporization of hydrocarbons and related compounds, R. C. Wilhort and B. J. Zwolinski, Texas A Research Foundation. College Station, Texas(1971). 329 pages.$10.00, AIChE J., 1972, 18, 6, 1278-1278, https://doi.org/10.1002/aic.690180637 . [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Beattie, Ingersoll, et al., 1942, 2
Beattie, James A.; Ingersoll, Henry G.; Stockmayer, Walter H., Vapor Pressures and Critical Constants of Isobutene, J. Am. Chem. Soc., 1942, 64, 3, 546-548, https://doi.org/10.1021/ja01255a021 . [all data]

Lamb and Roper, 1940
Lamb, Arthur B.; Roper, Edwin E., The Vapor Pressures of Certain Unsaturated Hydrocarbons, J. Am. Chem. Soc., 1940, 62, 4, 806-814, https://doi.org/10.1021/ja01861a032 . [all data]

Boublik, Fried, et al., 1984
Boublik, T.; Fried, V.; Hala, E., The Vapour Pressures of Pure Substances: Selected Values of the Temperature Dependence of the Vapour Pressures of Some Pure Substances in the Normal and Low Pressure Region, 2nd ed., Elsevier, New York, 1984, 972. [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

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Todd, S.S.; Parks, G.S., Thermal data on organic compounds. XV. Some heat capacity, entropy and free energy data for the isomeric butenes, J. Am. Chem. Soc., 1936, 58, 134-137. [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]

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]

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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]

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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]

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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]

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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]

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

Notes

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

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  Pc	Critical pressure
  T	Temperature
  Tboil	Boiling point
  Tc	Critical temperature
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  Vc	Critical volume
  ΔfusH	Enthalpy of fusion
  ΔfusS	Entropy of fusion
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔrS°	Entropy of reaction at standard conditions
  ΔvapH	Enthalpy of vaporization
  ΔvapH°	Enthalpy of vaporization at standard conditions
  ρc	Critical density

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