ChemInform Abstract: UNIMOLECULAR PROCESSES IN VIBRATIONALLY HIGHLY EXCITED CYCLOHEPTATRIENES. II. TEADY‐STATE PHOTOISOMERIZATION

Pyrolysis of 1.3.5.7‐Cyclooctatetraene, Semibullvalene, and 1.5‐Dihydropentalene in Shock Waves and in a Flow System (Part I)

“…First of all these results indicate that the rate constants kla,m(T) and klh,m(T) determined by two independent ways are consistent. A more accurate determination of the high pressure rate constants and the threshold energies of the reactions (R 1 a) and (R 1 b) will be possible using the results of COT decomposition measured in a static systim below lo00 K [29] where deviations from the high pressure limit are less important than in the present experiments. The results also show that an increase of the total gas concentration within the range in general accessible in shock wave experiments will not improve the approach of k , considerably.…”

“…The magnitude of the reaction barriers was obtained from the kinetic measurements (cf. text) estimated [29] heats of formations of the biradicals and a indicate that they could possibly be intermediates of the potential surfaces interconnecting COT and the decomposition products a+ CzH2 or the isomerization to 1.5-DHP and/or SBV, respectively. Also the isomerization between 1.5-DHP and SBV could, in principle, proceed via the biradical form a .…”

“…18 [8,13,15,21,22] for the stable compounds and from Ref. [29] for the biradicals. The shadowed areas indicate estimated uncertainties of the respective AH:.…”