Kinetics and Mechanism of the Thermal Gas-Phase Oxidation of Tetrachloroethene by Molecular Oxygen in Presence of Trifluoromethylhypofluorite, CF<sub>3</sub>OF
作者:Joanna Czarnowski
DOI:10.1524/zpch.1998.203.part_1_2.183
日期:1998.1.1
The oxidation of tetrachloroethene by molecular oxygen in presence of CF3OF has been studied at 314.0, 324.2, 334.1 and 344.3 K. The initial pressure of CF3OF was varied between 2.0 and 8.2 Torr, that of CCl2CCl2 between 8.7 and 21.7 Torr, that of O-2 between 33.2 and 730.7 Torr. Several runs were made adding N-2 at pressure Varying between 250.4 and 525.9 Torr. The major products were CCl3C(O)Cl and COCl2. CF3OCCl2C(O)Cl, CCl2FC(O)Cl, CF3OCCl2CCl2F and CCl2FCCl2F were formed in traces. The oxidation is a chain reaction. Its rate increases with total pressure. The following mechanism, where E = CCl2CCl2, R = CCl2FCCl2, CF3OCCl2CCl2 or CCl,3CCl2, R' = CCl2F, CF3OCCl2 or CCl3 and M = effective pressure, explains the experimental results:1) CF3OF+E-->R+CF3O 2) CF3O+E-->R3, 7) R+O-2+M-->RO2+M 4,8) 2RO(2)-->2RO+O-25) RO-->R'C(O)Cl+Cl 6) Cl+E-->CCl3CCl29) CCl3CCl2O-->CCl3C(O)Cl+Cl 10) CCl3CCl2O-->CCl3+COCl211) CCl3+O-2+M-->CCl3O2+M 12)CCl3O2+RO2-->CCl3O+RO+O-213) CCl3O-->COCl2+Cl 14) 2R-->recombination products,15) R+CF3OF-->RF+CF3Ok(9)=(3.0+/-1.4)X10(13)exp(-9.66+/-1 kcal mol(-1)/RT) s(-1).