21811-29-0Relevant articles and documents
Kinetics and mechanism of the reaction of CF3 radicals with NO2
Sehested, Jens,Nielsen, Ole John,Rinaldi, Carlos A.,Lane, Silvia I.,Ferrero, Juan Carlos
, p. 579 - 588 (1996)
The reaction of CF3 with NO2 was studied at 296 ± 2K using two different absolute techniques. Absolute rate constants of (1.6 ± 0.3) × 10-11 and (2.1-0.3+0.7) × 10-11 cm3 molecule-1 s-1 were derived by IR fluorescence and UV absorption spectroscopy, respectively. The reaction proceeds via two reaction channels: CF3 + NO2 → CF2O + FNO, (70 ± 12)% and CF3 + NO2 → CF3O + NO, (30 ± 12)%. An upper limit of 11% for formation of other reaction products was determined. The overall rate constant was within the uncertainty independent of total pressure between 0.4 to 760 torr.
Kinetic study of the reactions of CF3O2 radicals with Cl and NO
Louis, Florent,Burgess Jr., Donald R.,Rayez, Marie-Therese,Sawerysyn, Jean-Pierre
, p. 5087 - 5096 (2007/10/03)
Kinetic studies of the reactions CF3O2 + Cl and CF3O2 + NO were performed at room temperature in the gas phase using the discharge flow mass spectrometric technique (DFMS). The reactions were investigated under pseudo- first-order conditions with Cl or NO in large excess with respect to the CF3O2 radicals. The rate constant for the reaction CF3O2 + NO was measured at 298 K and the value of (1.6 ± 0.3) x 10-11 cm3 molecule-1 s-1 is in very good agreement with all previous values. For the reaction CF3O2 + Cl, we obtain a rate constant at 298 K of (4.2 ± 0.8) x 10-11 cm3 molecule-1 s-1 in excellent agreement with the only published value. Product analysis shows that this reaction occurs via the major reaction pathway CF3O2 + Cl → CF3O + ClO at room temperature. In addition, an ab initio theoretical study was performed to gain insights on the different postulated reaction pathways. There is a significant disagreement between experimental and ab initio values recommended for the formation enthalpies of CF2O, CF3O and related molecules produced in this system. Consequently, we provide self-consistent values of enthalpies based on isodesmic reactions for the CF3O2 + Cl reaction system using the G2, G2(MP2) and CBS-Q methods. These values are also compared with BAC-MP4 heats of formation calculated in this work.
Kinetics of the Reaction of CF3O with NO
Dibble, Theodore S.,Maricq, M. Matti,Szente, Joseph J.,Francisco, Joseph S.
, p. 17394 - 17402 (2007/10/02)
The reaction between CF3O and NO has been studied by laser flash photolysis/transient diode laser absorption over the range 213 K a small extent (Φ=0.15).A significant fraction of the CF3O (ca. 30percent) is born with sufficient internal excitation to dissociate into F2CO and F atoms.The presence of NO leads to additional F2CO formation.The analysis of this formation rate, as well as the NO loss rate, yields a temperature dependent rate constant of (4.4 +/- 1.5) x 10-11e(+100+/-88)/T cm3 s-1 for the CF3O + NO reaction.The measured rate constants agree well with previous results based on observations of CF3O disappearance.They confirm expectations that the reaction yields exclusively the products FNO and F2CO and that it serves as an efficient stratospheric sink for the CF3O radical.The reaction between CF3O and HCl has also been examined, and an upper limit of 2 x 10-13 cm3 s-1 has been determined for its rate constant at 295 K.The small rate constant for this reaction relative to the rapid removal of CF3O by NO severely limits the possibility that hydrofluorocarbons contribute to stratospheric ozone depletion by their CF3O degradation product liberating chlorine atoms from HCl.
