Library

X
Language
Preferred search index
Number of Hits per Page
Default Sort Criterion
Default Sort Ordering
Size of Search History
Default Email Address
Default Export Format
Default Export Encoding
Facet list arrangement
Maximum number of values per filter
Auto Completion
Feed Format
Maximum Number of Items per Feed
Permalink If you want to be able to use settings permanently, you must save your settings and then set a Bookmark to the permalink
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Electronic Resource  (3)
  • Diradical intermediates  (2)
  • Cyclopropene, 3,3-dimethyl-1-trimethylsilyl-  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Gas-Phase Kinetics of the Pyrolysis of Some 3,3-Dimethyl-1-(trimethylsilyl)-cyclopropenes  -  Unexpected Product Distribution in the Cyclopropene Rearrangement (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 237-245 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopropenes, 3,3-dimethyl-1-trimethylsilyl-substituted ; Cyclopropene, isomerisation ; Gas-phase kinetics ; Ring opening ; Diradical intermediates ; Cyclopropylidene intermediates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas-phase pyrolyses of 1,3,3-trimethyl-2-(trimethylsilyl)-cyclopropene (9), 3,3-dimethyl-1,2-bis(trimethylsilyl)cyclopropeneTextReactantlog (A/s-1)Ea/kj mol-1(kcal mol-1)913.41 ± 0.22192.1 ± 2.5(45.9 ± 0.6)1013.54 ± 0.19184.4 ± 2.1(44.1 ± 0.5)1112.17 ± 0.38124.6 ± 3.1(29.8 ± 0.7)(10), and 3,3-dimethyl-1-(methylthio)-2-(trimethylsilyl)cyclopropene (11) have been studied, and the pressure-independent Arrhenius parameters listed in the table were obtained. All three rearrangements are homogeneous, first-order and unimolecular reactions. Rather surprisingly all reactions give the corresponding isomeric allenes as the main products. Amongst possible mechanisms discussed, 10 is proposed to react via a cyclopropylidene intermediate, whilst the results for 9 and 11 throw light on the relative importance of the diradical- and vinylcarbene-type intermediates produced by cyclopropene ring opening.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270134
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Gas-Phase Kinetics of Pyrolysis of 3,3-Dimethylcyclopropene and Its 1-Trimethylsilyl Derivative The Effect of Silyl Substitution on Cyclopropene Isomerisation (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 637-642 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopropene, 3,3-dimethyl-1-trimethylsilyl- ; Cyclopropene, isomerisation ; Gas-phase kinetics ; Ring-opening of 3,3-dimethylcyclopropene ; Vinylcarbene intermediates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gas-Phasen-Kinetik der Pyrolyse von 3,3-Dimethylcyclopropen und seinem 1-Trimethylsilyl-Derivat. - Der Effekt der Silyl-Substitution auf die Cyclopropen-IsomerisierungDie Gasphasen-Pyrolyse von 3,3-Dimethylcyclopropen (1) im Temperaturbereich 185-225°C ergibt 3-Methyl-1-butin (2) (91%) und Isopren (3) (9%). Die Gasphasen-Pyrolyse von 3,3-Dimethyl-1-trimethylsilylcyclopropen (4) führt zu 3-Methyl-1-trimethylsilyl-1-butin (5) (99%) und trans-3-Methyl-1-trimethylsilyl-1,3-butadien (6) (1%). Beide Umlagerungen sind homogene, unimolekulare Reaktionen erster Ordnung mit den folgenden druck-unabhängigen Arrhenius-Parametern.Überraschenderweise desaktiviert die Trimethylsilyl-Gruppe das Cyclopropen in bezug auf seine Isomerisierung. Mögliche Mechanismen werden diskutiert.
    Notes: The gas-phase pyrolysis of 3,3-dimethylcyclopropene (1) in the temperature range of 185-225°C gives 3-methyl-1-butyne (2) (91%) and isoprene (3) (9%). The gas-phase pyrolysis of 3,3-dimethyl-1-trimethylsilylcyclopropene (4) in the temperature range of 195-235°C gives 3-methyl-1-trimethylsilyl-1-butyne (5) (99%) and trans-3-methyl-1-trimethylsilyl-1,3-butadiene (6) (1%). Both rearrangements are homogeneous, first-order, unimolecular reactions with the following pressure-independent Arrhenius parameters.Rather surprisingly, the trimethylsilyl group deactivates cyclopropene with respect to its isomerisation. Possible mechanisms are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220409
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Gas-Phase Kinetics of the Thermal 1-Alkoxy-1-vinylcyclopropane to 1-Alkoxy-1-cyclopentene Rearrangement (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 939-945 
    Details
    ISSN: 0009-2940
    Keywords: 1-Vinylcyclopropane ; 1-methoxy- ; 1-ethoxy- ; Vinylcyclopropane ; isomerization ; Gas-phase kinetics ; Ring expansion of 1-alkoxy-1-vinylcyclopropanes ; Diradical intermediates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title studies have been carried out with both 1-vinyl-1-cyclopropyl methyl ether (1-OMe) and 1-vinyl-1-cyclopropyl ethyl ether (1-OEt) in the temperature ranges 274.6-324.5 and 273.6 - 323.0°C, respectively. Both reactions predominantly give the vinylcyclopropane-cyclopentene (VCP-CP) rearrangement products 1-cyclopenten-1-yl methyl ether (2-OMe) and 1-cyclopenten-1-yl ethyl ether (2-OEt). Additionally, 2-OEt eliminates ethene (3) in a consecutive reaction at a lower reaction rate compared with the VCP-CP rearrangement. The rearrangements obey first-order kinetics and have been shown to be homogeneous, pressure-independent reactions with the following Arrhenius equations:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {1 - {\rm OMe:}} {{\rm lg}\left({k/s^{-1}} \right) = \left({13.89 \pm 0.23} \right) - \left({191.30 \pm 2.55{\rm kJ mol}^{-1}} \right)/RT\ln 10} \\\end{array} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {1 - {\rm OMt:}} {{\rm lg}\left({k/s^{-1}} \right) = \left({13.77 \pm 0.01} \right) - \left({188.80 \pm 1.85{\rm kJ mol}^{-1}} \right)/RT\ln 10} \\\end{array} $$\end{document}The Arrhenius parameters represent reliable values for general 1-vinyl-1-cyclopropyl alkyl ether→1-cyclopenten-1-yl-alkyl ether (1-OR→2-OR) rearrangements within a large temperature interval in the gas phase. The results support a mechanism proceeding via a diradical. The stabilizing effect of methoxy substitution is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240439
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...