Molecular beam study on infrared multiphoton dissociation of octafluorocyclobutane

Shock wave study and theoretical modeling of the thermal decomposition of c-C4F8

“…In agreement with the calculations of Yokoyama et al 14 The latter according to our calculations at somewhat higher energies than for reaction (1).…”

“…In addition, k 1 c k 2 is confirmed. We note that the conclusions about the two-step character of reaction ( 1) is also consistent with the molecular beam study of Yokoyama et al, 14 measuring the translational energy of the C 2 F 4 fragments in the multiphoton dissociation of c-C 4 F 8 .…”

“…The analogy to the mechanism of the decomposition of c-C 3 F 6 , involving an intermediate 1,3-biradical CF 2 CF 2 CF 2 , is obvious and also of interest. 5 Our present quantum-chemical calculations update and extend earlier work from Yokoyama et al 14 While the precision of our rate constant calculations will still leave something to be desired, the comparison of experiment and theory nevertheless should shed some light on the question of the relative importance of reactions (1) and (2).…”

Chain elongation during thermolysis of tetrafluoroethylene and hexafluoropropylene: Modeling of mechanistic hypotheses and elucidation of data needs

“…7 [1][2][3][4][5] (a set of low-temperature data [5] was not included These values of k 4 and k −4 give H 4 = −51.6 kcal/mol and S 4 = −48.0 cal/mol K. The comparable quantities from the "experimental" ("computational") data in Table 1 [97] have detected separate transition states for ring opening of c-C 4 F 8 to form the 1,4-biradical (step (-6)) and fragmentation of the latter to form C 2 F 4 (step (-5)), with the latter lying 5.0 [53] or 8.7 kcal/mol [97] above the…”

“…9. The levels for C 2 F 4 , c-C 4 F 8 , and the 1,4-biradical are the "experimental" values from Table 1; that for TS1 is based on E 4 as representing the rate-determining step (strictly speaking we should correct from E to ‡ H but the correction will be no more than the uncertainties arising from the lack of C p corrections); and that for TS2 is based on computation [97]. The estimation of f H 298 (1,4-biradical) is an upper limit to the extent that it is stabilized by factors similar to those that have been suggested to stabilize the 1,3-biradical, as discussed below; hence the valley is which it lies may be somewhat deeper.…”