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

C. J. COBOS; K. HINTZER; L. SOLTER; E. TELLBACH.; A. THALER; J. TROE

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2015 vol. 17 p. 32219 - 32224

1463-9076

The thermaldissociation of octafluorocyclobutane, c-C4F8, wasstudied in shock waves over the range 1150?2300 K by recording UV absorptionsignals of CF2. It was found that the primary reaction nearly exclusivelyproduces 2 C2F4 which afterwards decomposes to 4 CF2.A primary reaction leading to CF2 + C3F6 isnot detected (an upper limit to the yield of the latter channel was found to beabout 10 percent). The temperature range of earlier single pulse shock waveexperiments was extended. The reaction wasshown to be close to its high pressure limit. Combining high and lowtemperature results leads to a rate constant for the primary dissociation of k1= 1015.97 exp(-310.5 kJ mol-1/RT) s-1 in the range630?1330 K, over which k1 varies over nearly 14 orders of magnitude.Calculations of the energetics of the reaction pathway and the rate constantssupport the conclusions from the experiments. Also they shed light on therole of the 1,4-biradical CF2CF2CF2CF2as an intermediate of the reaction.