The Thermal Decomposition of cis-1,2-Dimethylcyclobutane 1

The photolysis of trans-3,4-dimethylcyclopentanone has been investigated in the gas phase at 100°C using light of 206 and 193 nm. The photolytic products are propene, 1,2-dimethylcyclobutane, and the butene isomers. Small quantities of 3,4-dimethylpent-4-enal were also detected. Relative yields of these products were determined as a function of the ketone pressure and also of that of added nitrogen. A mechanism for the photochemical decomposition based on that suggested for the photolysis of cyclopentanone using short wavelength radiation, is consistent with the experimental results and is simpler than that required to account for the long wavelength photolysis reported earlier.

Section: Discussionmentioning

confidence: 99%

The photolysis of trans‐3,4‐dimethylcyclopentanone. II. Short Wavelengths

Becerra

Frey

1990

“…The standard heat of formation and the standard entropy to the calculation of the standard entropy. The 1,2-dimethylcyclobutane isomer was chosen because its rate constant for decomposition has been measured [4], while the decomposition of 1,3-dimethylcyclobutane has not been studied. The thermodynamic and kinetic properties of the latter are very likely similar to those for 1,2-dimethylcyclobutane, so that the constants for formation of either isomer are probably very close.…”

Section: Calculationsmentioning

confidence: 99%

“…l h e enthalpy and entropy changes for the equilibria were obtained using the standard thermodynamic quantities at 298°K and are listed in (4), and (7) the rate constants were calculated first in units of atm-l sec-l and then converted to cc m-l sec-' at the particular temperature.…”

Section: Calculationsmentioning

confidence: 99%

See 1 more Smart Citation

Mechanism of the bimolecular reactions of ethylene and propylene

Back

1970

Rate constants for the bimolecular reactions of ethylene and propylene to form radicals and to form cyclobutane or its derivatives have been calculated using thermodynamic and kinetic data. Comparison of these rates with the kinetics of the thermal reactions of ethylene and propylene show that cyclobutane and its derivatives are probably not important intermediates in the processes forming radicals.

“…There is little doubt that a triplet state is involved [2-41, but it is uncertain to what extent an excited singlet state also participates. The present work presents a further study on a substituted cyclopentanone on which there has previously only been some preliminary experiments [5].…”

Section: Introductionmentioning

confidence: 98%

The photolysis of 3,4‐dimethylcyclopentanone

Becerra

Frey

1984

The photolysis of trans-3,4-dimethylcyclopentanone has been studied in the gas phase, principally at 313 nm. However, a few experiments have also been performed using laser sources at 308 and 325 nm. Additionally, experiments were also carried out using the cis isomer. The major products produced by all three wavelengths and in the temperature range 100 to 150°C were propene, 1,2-dimethylcyclobutane, carbon monoxide, and 3,4-dimethylpent-4-en-a1. The formation of the cyclobutane was stereospecific and the effects of temperature, pressure, and wavelength on the relative product yields could be rationalized in terms of a mechanism involving the formation of a vibrationally excited triplet state which could yield both hydrocarbons and the aldehyde and a nonexcited triplet yielding only the aldehyde. Some high intensity experiments with an exciplex laser at 308 nm gave results which could be due to the occurrence of some two photon absorption by the cyclopentanone or absorption by an excited intermediate. The results are compared with those previously reported for other substituted cyclopentanones.