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Journal ArticleDOI

Kinetics of the thermal decomposition of polyfluoroalkylsilicon compounds

01 Jan 1965-Chemical Communications (london) (The Royal Society of Chemistry)-Iss: 16, pp 382-384
About: This article is published in Chemical Communications (london).The article was published on 1965-01-01. It has received 7 citations till now. The article focuses on the topics: Thermokinetics & Thermal decomposition.
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Journal ArticleDOI
TL;DR: In this article, the β-elimination kinetics of 2,2-dihaloethyltrihalosilanes in the gas phase has been studied computationally using density functional theory (DFT) along with the M06-2x exchange correlation functional and the aug-cc-pVTZ basis set.
Abstract: The β-elimination kinetics of 2,2-dihaloethyltrihalosilanes in the gas phase has been studied computationally using density functional theory (DFT) along with the M06-2x exchange–correlation functional and the aug-cc-pVTZ basis set. The calculated energy profiles have been supplemented with calculations of rate constants under atmospheric pressure and in the fall-off regime, by means of transition state theory (TST), variational transition state theory (VTST), and statistical Rice–Ramsperger–Kassel–Marcus (RRKM) theory. Activation energies and rate constants obtained using the M06-2x/aug-cc-pVTZ approaches are in good agreement with the available experimental data. Analysis of bond order, natural bond orbitals, and synchronicity parameters suggests that the β-elimination of the studied compounds can be described as concerted and slightly asynchronous. The transition states of these reactions correspond to four-membered cyclic structures. Based on the optimized ground state geometries, a natural bond orbital (NBO) analysis of donor–acceptor interactions also show that the resonance energies related to the electronic delocalization from $$\sigma_{{{\text{C}}_{ 1} {-}{\text{C}}_{ 2} }}$$ bonding orbitals to $$\sigma^{*}_{{{\text{C}}_{ 2} - {\text{Si}}_{ 3} }}$$ antibonding orbitals, increase from 2,2-difluoroethyltrifluorosilane to 2,2-dichloroethyltrichlorosilane and then to 2,2-dibromoethyltriboromosilane. The decrease of $$\sigma_{{{\text{C}}_{ 1} {-}{\text{C}}_{ 2} }}$$ bonding orbitals occupancies and increase of the $$\sigma^{*}_{{{\text{C}}_{ 2} - {\text{Si}}_{ 3} }}$$ antibonding orbitals occupancies through $$\sigma_{{{\text{C}}_{ 1} - {\text{C}}_{ 2} }} \to \sigma^{*}_{{{\text{C}}_{ 2} - {\text{Si}}_{ 3} }}$$ delocalizations could facilitate the β-elimination of the 2,2-difluoroethyltrifluorosilane compound, compared to 2,2-dichloroethyltrichlorosilane and 2,2-dibromoethyltriboromosilane.

13 citations

Journal ArticleDOI
TL;DR: In this paper, the absorption and dissociation of 1,2-dichloroethyltrifluorosilane molecules under the action of pulsed TEA CO2 laser were experimentally studied.
Abstract: Infrared multiphoton absorption and dissociation of 1,2-dichloroethyltrifluorosilane molecules under the action of pulsed TEA CO2 laser were experimentally studied. The composition of dissociation products was analyzed. The only products of dissociation have been found to be stable molecules: chloroethylene and trifluorochlorosilane. Dissociation proceeds via chlorine atom transfer from carbon to silicon. The silicon isotope-selective infrared multiphoton dissociation was performed at different wavelengths of the CO2-laser radiation. High degrees of silicon isotope separation have been achieved.

5 citations

Journal ArticleDOI
TL;DR: In this article, the gas phase β-elimination kinetics of 2,2-difluoroethyltrifluorosilane (1), 2.2-dimethyltrimethylsilane (2), 2, 2-dimethyltetrafluoride (3), and 2.5-dimethyltrimethylfluorides (4) were investigated using the CBS-QB3 approach.

5 citations

Journal ArticleDOI
TL;DR: The presence of α‐chlorine atom in a silicon organic compound brings about a significant improvement in multiple photon dissociation characteristics and an essential increase in isotopic selectivity.
Abstract: Infrared multiphoton absorption and dissociation of chloromethyltrifluorosilane molecules under the action of pulsed transversely excited atmospheric pressure CO2 laser were experimentally studied. Dissociation products were analyzed. The dissociation proceeds via chlorine atom transfer from carbon to silicone. High degrees of silicon isotope separation were achieved. The presence of a-chlorine atom in a silicon organic compound brings about a significant improvement in multiple photon dissociation characteristics and an essential increase in isotopic selectivity.

5 citations


Cites methods from "Kinetics of the thermal decompositi..."

  • ...Dissociation energies obtained from the kinetics data were within the range of 100–160 kJ mol (23)....

    [...]

Journal ArticleDOI
TL;DR: There is a large body of work on halogen derivatives of alkyl(or aryl)halogenosilanes and tetrasubstituted silanes as discussed by the authors.
Abstract: In recent years there have been many investigations in the field of organosilicon compounds containing halogen-substituted organic groups. These investigations offer prospects of the use of these compounds in the synthesis of polyorganosiloxanes. The extensive data on methods of synthesis of halogen derivatives of alkyl(or aryl)halogenosilanes and tetrasubstituted silanes, their properties, and use are scattered in many periodicals. Monographs and review articles have so far examined only isolated aspects of the chemistry of organosilicon compounds. This has stimulated us to survey the accumulated experimental results, the analysis of which even now allows definite regularities to be found in the occurrence of certain reactions and processes in the synthesis and conversions of halogen derivatives of organosilicon compounds. There is a bibliography of 677 references.

3 citations