- Relative Rate Constants for the Reactions of CF3OF with Olefins in Solution
-
The addition reactions of CF3OF to chloro fluoro olefins have been studied in solution at low temperature (-78, -105 deg C), and their relative rate constants have been determined using the kinetic approach of competition reactions.The reactivity and regio- and stereoselectivity are consistent with a free radical chain-propagating reaction in which the alkenes are attacked by the CF3O* radical generated by homolytic cleavage of the O-F bond in the CF3OF molecule.
- Navarrini, W.,Russo, A.,Tortelli, V.
-
p. 6441 - 6443
(2007/10/03)
-
- Kinetics and Mechanism of the Thermal Gas-phase Oxidation of Trichloroethene by Molecular Oxygen in Presence of Trifluoromethylhypofluorite, CF3OF
-
The oxidation of trichloroethene by molecular oxygen in presence of CF3OF has been studied at 293.8, 313.8 and 333.5 K.The initial pressure of CF3OF was varied between 0.8 and 9.5 Torr, that of CHClCCl2 between 5.4 and 54.6 Torr and that of O2 between 19.9 and 603.5 Torr.Several runs were made adding N2 at pressures varying from 96.4 to 663.2 Torr.The major product was CHCl2C(O)Cl, COCl2, HCl and CO were formed in minor amounts.Traces of CF3OCHClC(O)Cl, CHClFC(O)Cl, CF3OCHClCCl2F and CHClFCCl2F were detected.The oxidation is a chain reaction, whose rate increases with total pressure.The following mechanism, where E = CHClCCl2, R = CHClFCCl2, CF3OCHClCCl2 or CHCl2CCl2, R' = CHClF, CF3OCHCl or CHCl2 and M = effective pressure, explains the experimental results: (1) CF3OF + E = R + CF3O, (2) CF3O + E = R, (3,7) R + O2 + M = RO2 + M, (4,8) 2RO2 = 2RO + O2, (5,9) RO = R'C(O)Cl + Cl, (6) Cl + E = R, (10) 2R = recombination products, (11) R + CF3OF = RF + CF3O, (12) RO2 + E = RO2(E), (13) RO2(E) = products (e.g., R, HCl, CO, COCl2), k9 = 1.1 +/- 1E14 exp(-39.5 +/- 10 kJ mol-1/RT) s-1, k12 = 9.4 +/- 8E8 exp(-27.0 +/- 11 kJ mol-1/RT) dm3 mol-1 s-1. - Keywords: Gas-phase, Oxidation, Trichloroethene, Trifluoromethylhypofluorite, Chlorine atoms
- Czarnowski, J.
-
p. 103 - 118
(2007/10/03)
-