1,2-Butadiene

• Formula: C₄H₆
• Molecular weight: 54.0904
• IUPAC Standard InChI: InChI=1S/C4H6/c1-3-4-2/h4H,1H2,2H3 Copy

  
• IUPAC Standard InChIKey: QNRMTGGDHLBXQZ-UHFFFAOYSA-N Copy
• CAS Registry Number: 590-19-2
• 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: Allene, methyl-; Methylallene; CH2=C=CHCH3; Buta-1,2-diene
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Phase change 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)
  • Computational Chemistry Comparison and Benchmark Database
  • Gas Phase Kinetics Database
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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: Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of liquid

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 as indicated in comments:
B - John E. Bartmess
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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

C₄H₅^- +  =

By formula: C₄H₅^- + H⁺ = C₄H₆

=

By formula: C₄H₆ = C₄H₆

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
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C₄H₆⁺ (ion structure unspecified)

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₄H₅^- +  =

By formula: C₄H₅^- + H⁺ = C₄H₆

References

Go To: Top, Condensed phase thermochemistry 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.

Aston and Szasz, 1947
Aston, J.G.; Szasz, G.J., The thermodynamics of butadiene-1,2 from calorimetric and spectroscopic data, J. Am. Chem. Soc., 1947, 69, 3108-3114. [all data]

Prosen, Maron, et al., 1949
Prosen, E.J.; Maron, F.W.; Rossini, F.D., Heat of isomerization of the two butadienes, J. Res. NBS, 1949, 42, 269-275. [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]

Beez, Bieri, et al., 1973
Beez, M.; Bieri, G.; Bock, H.; Heilbronner, E., The ionization potentials of butadiene, hexatriene, andtheir methyl derivatives: evidence for through space interaction between double bond π-orbitals and non-bonded pseudo-π orbitals of methyl groups?, Helv. Chim. Acta, 1973, 56, 1028. [all data]

Parr and Elder, 1968
Parr, A.C.; Elder, F.A., Photoionization of 1,3butadiene, 1,2-butadiene, allene, and propyne, J. Chem. Phys., 1968, 49, 2659. [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]

White, Carlson, et al., 1974
White, R.M.; Carlson, T.A.; Spears, D.P., Angular distribution of the photoelectron spectra for ethylene, propylene, butene and butadiene, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 59. [all data]

Brogli, Crandall, et al., 1973
Brogli, F.; Crandall, J.K.; Heilbronner, E.; Kloster-Jensen, E.; Sojka, S.A., The photoelectron spectra of methyl-substituted allenes and of tetramethyl-bisallenyl, J. Electron Spectrosc. Relat. Phenom., 1973, 2, 455. [all data]

Collin and Lossing, 1957
Collin, J.; Lossing, F.P., Ionization and dissociation of allene, propyne, 1-butyne, and 1,2- and 1,3-butadienes by electron impact; the C₃H₃⁺ ion, J. Am. Chem. Soc., 1957, 79, 5848. [all data]

Notes

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• Symbols used in this document:
  

  AE	Appearance energy
  Cp,liquid	Constant pressure heat capacity of liquid
  S°liquid	Entropy of liquid at standard conditions
  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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