Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations

Grützmacher H-F, Büchner M, Zipse H (2005)
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 241(1): 31-42.

Zeitschriftenaufsatz | Veröffentlicht | Englisch
 
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Autor*in
Grützmacher, Hans-FriedrichUniBi; Büchner, Michael; Zipse, Hendrik
Abstract / Bemerkung
Continuing the studies of ion/molecule reactions of haloalkene radical cations with nucleophiles, the reactions of the radical cations of 2-chloropropene, 1(.+), and 2-bromopropene. 2(.+) with methanol and ethanol, respectively, have been investigated by FT-ICR spectrometry and by computational analysis using DFT calculation (BHLYP/6-311 + G(2d,p)//BHLYP/6-31 + G(d) level). Only slow reactions (reaction efficiency <1%) are observed for 1(.+)/methanol and 2(.+)/methanol. Slow proton transfer is the main process for 1(.+)-methanol besides minor addition of methanol to 1(.+) followed by loss of HCl or Cl-.. Addition of methanol accompanied by loss of Br-. is the exclusive process observed for 2(.+)/methanol. In contrast, both 1(.+) and 2(.+) react efficiently with ethanol yielding protonated acetaldehyde as the exclusive (1(.+)) or by far dominant (2(.+)) primary reaction product. The computational analysis of these ion/molecule reactions shows that in the case of 1(.+)/methanol and 2(.+)/methanol all processes are either endothermic or blocked by large activation energies. Nonetheless, addition of methanol to the ionized C-C double bond of 1(.+) or 2(.+) is exothermic, yielding in each case a pair of isomeric beta-distonic methoxonium ions. A new reaction mechanism has been found for the HX (X = Cl, Br) elimination from the less stable isomer of the distonic intermediates. Further, an energetically favorable transition state has been detected for hydrogen atom transfer from the alpha-CH2, group of alcohol to the halogenoalkene radical cations. These findings lead to a revised mechanism of the oxidation process and provide a plausible explanation for the excessive HID exchange between 1(.+) and CD(3)0H during their slow reaction. (C) 2004 Elsevier B.V. All rights reserved.
Stichworte
reaction mechanism; alkene radical cation; substitution; elimination; oxidation; DFT calculation; FT-ICR; ion-molecule reaction; alcohol
Erscheinungsjahr
2005
Zeitschriftentitel
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
Band
241
Ausgabe
1
Seite(n)
31-42
ISSN
1387-3806
Page URI
https://pub.uni-bielefeld.de/record/1605173

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Grützmacher H-F, Büchner M, Zipse H. Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY. 2005;241(1):31-42.
Grützmacher, H. - F., Büchner, M., & Zipse, H. (2005). Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY, 241(1), 31-42. https://doi.org/10.1016/j.ijms.2004.10.012
Grützmacher, Hans-Friedrich, Büchner, Michael, and Zipse, Hendrik. 2005. “Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations”. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 241 (1): 31-42.
Grützmacher, H. - F., Büchner, M., and Zipse, H. (2005). Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 241, 31-42.
Grützmacher, H.-F., Büchner, M., & Zipse, H., 2005. Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY, 241(1), p 31-42.
H.-F. Grützmacher, M. Büchner, and H. Zipse, “Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations”, INTERNATIONAL JOURNAL OF MASS SPECTROMETRY, vol. 241, 2005, pp. 31-42.
Grützmacher, H.-F., Büchner, M., Zipse, H.: Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY. 241, 31-42 (2005).
Grützmacher, Hans-Friedrich, Büchner, Michael, and Zipse, Hendrik. “Ion/molecule reactions of 2-chloro- and 2-bromopropene radical cations with methanol and ethanol - FT-ICR spectrometry and DFT calculations”. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 241.1 (2005): 31-42.
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