Pyrolysis of cyclobutane

Beadle, Peter C.; Golden, David M.; King, Keith D.; Benson, Sidney W.

doi:10.1021/ja00764a008

Cited by 28 publications

(17 citation statements)

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“…Beadle et al [19] experimentally studied the pyrolysis of cyclobutane and reported rate parameters for the ring opening of c-C 4 H 8 (k 1-2 and k 2-1 ) and for the decomposition of the biradical in C 2 H 4 (k 2-C2H4 ).…”

Section: Cyclobutanementioning

confidence: 99%

“…At a given temperature, the global rate constant can be calculated from rate constants given by equations (18) and (19) and equilibrium constant in order to have the ratio of boat and chair conformations. Thus, we obtained the following expression for the global rate constant: …”

Section: Cyclohexanementioning

confidence: 99%

“…Thermal decomposition of cyclobutane has been experimentally studied too and rate constants for the ring opening leading to the formation of two ethylene molecules have been measured [15][16][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Detailed Kinetic Study of the Ring Opening of Cycloalkanes by CBS-QB3 Calculations

et al. 2006

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This work reports a theoretical study of the gas phase unimolecular decomposition of cyclobutane, cyclopentane and cyclohexane by means of quantum chemical calculations. A biradical mechanism has been envisaged for each cycloalkane, and the main routes for the decomposition of the biradicals formed have been investigated at the CBS-QB3 level of theory. Thermochemical data (∆H°f, S°, C°p) for all the involved species have been obtained by means of isodesmic reactions. The contribution of hindered rotors has also been included. Activation barriers of each reaction have been analyzed to assess the 1 energetically most favorable pathways for the decomposition of biradicals. Rate constants have been derived for all elementary reactions using transition state theory at 1 atm and temperatures ranging from 600 to 2000 K. Global rate constant for the decomposition of the cyclic alkanes in molecular products have been calculated. Comparison between calculated and experimental results allowed to validate the theoretical approach. An important result is that the rotational barriers between the conformers, which are usually neglected, are of importance in decomposition rate of the largest biradicals. Ring strain energies (RSE) in transition states for ring opening have been estimated and show that the main part of RSE contained in the cyclic reactants is removed upon the activation process.

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Section: Cyclobutanementioning

confidence: 99%

Section: Cyclohexanementioning

confidence: 99%

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Detailed Kinetic Study of the Ring Opening of Cycloalkanes by CBS-QB3 Calculations

et al. 2006

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“…The changes in molecular frequencies were estimated by the methods of Benson [2] and by analogy with the transition-state complexes for cyclobutane [20] and isopropenylcyclobutane [ 11. The breaking C-C bond in the biradical transition state was lengthened by 1 A,…”

Section: Cyclobutyl Cyanidementioning

confidence: 99%

Very low‐pressure pyrolysis of cyclobutyl cyanide. The cyano stabilization energy

King

Goddard

1975

Int J of Chemical Kinetics

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A very low-pressure pyrolysis (VLPP) apparatus has been constructed and shown to yield kinetic data consistent with other VLPP systems. The technique has been applied to the pyrolysis of cyclobutyl cyanide over the temperature range of 833-1203'K.The reaction was found to proceed via a single pathway to yield ethylene and vinyl cyanide. If A , is based on previous high-pressure data for this reaction and for cyclobutane pyrolysis, then RRKM theory calculations show that the experimental unimolecular rate constants are consistent with the high-pressure Arrhenius parameters given by The cyano group reduces the activation energy for cyclobutane pyrolysis by 6 f 1 kcall mole, and on the basis of a biradical mechanism this value may be attributed to the cyano stabilization energy.

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“…Experimental data on systems of this type will enable us to exploit our new computational techniques (21. For these studies we use the experimental technique of very low-pressure pyrolysis (VLPP) [4] at pressures such that gas-gas collisions compete with gas-wall collisions [5). As a prelude to energy transfer experiments we have studied the decomposition of CBCL under standard VLPP conditions (that is, where collisional activation is almost entirely via gas-wall collisions) in order to provide confirmation of the unimolecularity of the reactions and as a check on whether the behavior of the reactions in the falloff region is consistent with the high-pressure Arrhenius parameters found by CF.…”

Section: King Caynor and Gilrehtmentioning

confidence: 99%

Competitive unimolecular reactions at low pressures. The pyrolysis of cyclobutyl chloride

King

Gaynor

Gilbert

1979

Int J of Chemical Kinetics

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The thermal decomposition of cyclobutyl chloride has been investigated over the temperature range of 892-1150 K using the technique of very low-pressure pyrolysis (VLPP). The reaction proceeds via two competitive unimolecular channels, one to yield ethylene and vinyl chloride and the other to yield 1,3-butadiene and hydrogen chloride, with the latter being the major reaction under the experimental conditions. With the usual assumption that gas-wall collisions are "strong," RRKM calculations, generalized to take into account two competing pathways, show that the experimental unimolecular rate constants are consistent with the high-pressure Arrhenius parameters given by log kl(sec-') = (14.8 f 0.3) -(61.1 1.0)/8 for vinyl chloride formation and log kz(sec-1) = (13.6 f 0.3) -(55.7 f 1.0)/8 for 1,3-butadiene formation, where 8 = 2.303 R T kcal/mol. The A factors were assigned from previous high-pressure low-temperature data of other workers assuming a four-center transition state for 1,2-HC1 elimination and a chlorine-bridged biradical transition state for vinyl chloride formation. The activation energies are in good agreement with the high-pressure results which were obtained with a conventional static system. The difference in critical energies is 4.6 kcal/mol. IntroductionThe thermal decomposition of cyclobutyl chloride (CBCL) in a conventional static system has been studied by Cocks and Frey (CF) [l]. Over the temperature range of 667-776 K and the pressure range of 28-90 torr the decomposition was found to proceed by two first-order pathways, one yielding ethylene and vinyl chloride and the other yielding HCl and 1,3-butadiene, the latter presumably via the intermediate formation of cyclobutene:

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Pyrolysis of cyclobutane

Cited by 28 publications

References 0 publications

Detailed Kinetic Study of the Ring Opening of Cycloalkanes by CBS-QB3 Calculations

Detailed Kinetic Study of the Ring Opening of Cycloalkanes by CBS-QB3 Calculations

Very low‐pressure pyrolysis of cyclobutyl cyanide. The cyano stabilization energy

Competitive unimolecular reactions at low pressures. The pyrolysis of cyclobutyl chloride

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