Kinetics of the thermal decomposition of <i>trans</i>‐1,2‐dicyanocyclobutane

King, Keith D.; Goddard, Richard D.

doi:10.1002/kin.550100504

Cited by 6 publications

(5 citation statements)

References 22 publications

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“…The propargyl radicals are thermally stable under the experimental conditions, so either they escape from the reactor and reach the quadrupole ion source or they may abstract hydrogen atoms from the walls (inside or outside the reactor [ll]) to give propyne andlor allene [4,6]. Thus both the retro-ene and the bond fission pathways yield the same molecular products, but propargyl radicals (easily detected a t low electron energy [4,6]) and hydrogen atoms (and also H2 formed from recombination of hydrogen atoms at the walls) are unique to bond fission. However, because the fraction of atoms and free radicals which is converted to molecular species before reaching the ion source cannot be quantified, the bond fission and molecular pathways may not be separated quantitatively, only qualitatively.…”

Section: Resultsmentioning

confidence: 99%

“…Tsang's shock-tube results seem to be quite reliable and therefore may be used as the basis for assigning some Arrhenius parameters to the reactions in question. It now seems to be well established, from both shock-tube [1,2] and VLPP studies [4,6], that AH&oo Tsang's shock-tube studies [ 1,2] have yielded A factors of 1012.3-10':'.' sec-' a t (7') = 1100 K for the retro-ene decomposition of 4-methylhex-1 -yne, 5-methylhex-l-yne, hex-1-yne, 6-methylhept-2-yne, and 4-methylpent-1-yne.…”

Section: Resultsmentioning

confidence: 99%

“…The transition-state models were as for previous similar calculations [4][5][6][7]. A fixed six-membered ring transition-state model was used for the PRE = E , (CsH.…”

Section: Resultsmentioning

confidence: 99%

“…If the hydrocarbon transition states are essentially nonpolar, the observed trend is consistent with the changes in C-H bond energy. This is supported by the much higher rate for hepta-1,6-diyne where the relevant C-H bond is propargylic and therefore 8.7 kcal/mol weaker than a primary C-H bond [4][5][6]. An exception to the trend is 6-methylhept-2-yne which has a methyl substituent a t the acceptor site for the hydrogen transfer.…”

Section: Resultsmentioning

confidence: 99%

“…Other studies of alkyne decomposition have been carried out using the VLPP technique [3]. The kinetics of the bond fission process in but-1-yne [4], 3,3-dimethylbut-l-yne [5], and 4-phenylbut-1-yne [6] have been reported. The structures of these compounds preclude the retro-ene pathway which requires a carbon chain 2 Cs.…”

Section: Introductionmentioning

confidence: 99%

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Very low‐pressure pyrolysis (VLPP) of pentynes. I. Kinetics of the retro‐ene decomposition of pent‐1‐yne

King

1981

Int J of Chemical Kinetics

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T h e thermal unimolecular decomposition of pent-1 -yne has been investigated over the temperature range of 923-1 154 K using the technique of very low-pressure pyrolysis (VLPP). Under the experimental conditions the reaction proceeds predominantly via a molecular retro-ene pathway to yield allene and ethylene. There was some evidence for the occurrence of the higher energy C:1-C4 bond fission pathway a t the high end of the temperature range. Interpretation of the data with the aid of RRKM theory and taking into account a decrease in gas-wall collision efficiency with temperature yields the following high-pressure rate constant expression for the retro-ene pathway: log k (see-') = (12.8 f 0.4) -(57.0 f 2.0)/0 a t 1100 K where 0 = 2.303 RT kcal/mol and the A factor was assigned from the results of shock-tube studies of similar molecules. These rate parameters are independent of the inclusion of the bond fission pathway in the KRKM calculations. T h e results are compared with previous data on the retro-ene decomposition of alkynes.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…The transition-state models were as for previous similar calculations [4][5][6][7]. A fixed six-membered ring transition-state model was used for the PRE = E , (CsH.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Very low‐pressure pyrolysis (VLPP) of pentynes. I. Kinetics of the retro‐ene decomposition of pent‐1‐yne

King

1981

Int J of Chemical Kinetics

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Zur Kenntnis der Kohlenstoff-Kohlenstoff-Bindung

Rüchardt

Beckhaus

1980

Angew. Chem.

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Professor R o y Huisgen zum 60. Geburtstag gewidmetIm vorliegenden Aufsatz wird versucht, die klassische Frage: ,,Wie beeinflussen Zahl und Art von Substituenten die Starke von C-C-Einfachbindungen?" mit dem modernen Instrumentarium der physikalischen organischen Chemie zu beantworten. Ausgehend von den Arbeiten Karl Zieglers wurden dazu die Produkte und die Kinetik der Thermolyse einer gro8en Zahl hochverzweigter aliphatischer Kohlenwasserstoffe sowie deren phenyl-oder cyansubstituierten Derivaten untersucht. Bei jeder dieser Verbindungsklassen wurde ein h e a r e r Zusammenhang zwischen der freien Aktivierungsenthalpie der homolytischen Spaltung der schwachsten C-CBindung und der Spannungsenthalpie im Grundzustand festgestellt. Damit ist es gelungen, sterische und elektronische Effekte bei der Spaltung der C C-Bindung quantitatiu zu trennen. Durch experimentelle Strukturbestimmungen und durch Kraftfeldrechnungen wurde der Einflu8 der GruppengroBe auf Bindungswinkel und Bindungslangen sowie auf das konformative Verhalten der Modellverbindungen studiert. Es wurden dabei C-C-Bindungslangen bis 164 pm, Bindungswinkel am tetrakoordinierten Kohlenstoff bis 126" und ungewohnliche ekliptische und gauche-Vorzugskonformationen gefunden.

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Towards an Understanding of the Carbon‐Carbon Bond

Rüchardt

Beckhaus

1980

Angew. Chem. Int. Ed. Engl.

146

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Dedicated to Professor Rorf Huisgen on the occasion of his 60th birthdayIn this essay, the classical question of "the influence of the number and kind of substituents on the strength of the C-C bond", is pursued with the modern tools of contemporary physical organic chemistry. Based on the work of Karl Ziegler, the products and kinetics of thermolysis of a large number of highly branched aliphatic hydrocarbons and phenyl-or cyano-substituted derivatives were investigated. For each class of compounds, a linear relationship was found between the free enthalpy of activation of the homolytic cleavage of the weakest C-C bond and the strain energy in the ground state. These relationships permitted a quantitative separation of steric and electronic effects on the cleavage of C-C bonds. The influence of the size of the substituent groups on bond angles, bond lengths, and the conformational behavior of model compounds was studied by means of experimental structure determinations and force field calculations. C-C bond lengths up to 164 pm, bond angles at tetracoordinate carbon as large as 126", and unusual eclipsed and gauche preferred conformations were found.

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Kinetics of the thermal decomposition of trans‐1,2‐dicyanocyclobutane

Cited by 6 publications

References 22 publications

Very low‐pressure pyrolysis (VLPP) of pentynes. I. Kinetics of the retro‐ene decomposition of pent‐1‐yne

Very low‐pressure pyrolysis (VLPP) of pentynes. I. Kinetics of the retro‐ene decomposition of pent‐1‐yne

Zur Kenntnis der Kohlenstoff-Kohlenstoff-Bindung

Towards an Understanding of the Carbon‐Carbon Bond

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