753-56-0Relevant articles and documents
Formation of bromodifluoroacetyl fluoride, CF2BrC(O)F, in the thermal gas-phase oxidation of bromotrifluoroethene, CF2CFBr, initiated by trifluoromethylhypofluorite, CF3OF
Czarnowski, Joanna
, p. 736 - 739 (2008/09/16)
The oxidation of CF2CFBr by molecular O2, initiated by CF3OF, has been studied at 273, 253.5, 239 and 218 K. The initial pressure of CF3OF was varied between 0.9 and 2.4 Torr, that of CF2CFBr between 11.5 and 30.7 Torr and that of O2 between 42.5 and 100.7 Torr. The main product was CF2BrC(O)F (yields 81-95% based on the CF2CFBr consumed). Minor amounts of C(O)F2 and C(O)FBr and traces of bromotrifluoroethene epoxide were also formed. The reaction is a chain reaction with bromine atoms as chain carriers. Its basic steps are: the thermal generation of CF3O{radical dot} radical by abstraction of fluorine atom from CF3OF, chain initiation by addition of CF3O{radical dot} to the double bond of alkene, leading, in presence of O2, to the formation of bromine atom and chain propagation by the reaction of bromine atom with CF2CFBr, originating CF2BrCFBrO{radical dot} radical. The predominant fate of the latter is the bromine atom extrusion with C{single bond}C bond scission playing the minor role. The full mechanism is postulated.
OXYDATION ET COMBUSTION DES SYSTEMES H2-O2-N2-CF3Br ENTRE 400 ET 500 DEG C
Lemahieu, Joseph,Antonik, Stanislas
, p. 641 - 648 (2007/10/02)
The physico-chemical and analytic studies of the oxidation and combustion of the H2-O2-N2-CF3Br mixtures are performed by means of the pyrometer method between 400 and 500 deg C.The reaction is followed as a function of time by measuring the pressure variation and the light emission when flames appear.Some of the formed products are analysed by infra-red spectroscopy (CO2, CF2O, CF3OX with X = F and H, CF3H and FBrCO), and by polarography (mainly HX produced in the vessel on the one hand, and as a result of the hydrolysis reactions of halogens, CF2O, FBrCO and CF3OX on the other hand).In the considered temperature interval, the fundamental fact consists in replacing the branching chains oxidation reaction of hydrogen by a thermal chains reaction induced by the X2-H2 mixtures (mostly with the X2 = F2 mixture).The existence of these thermal chains might particularly explain why, on the whole, CF3Br is a rather bad inhibitor of the hydrogen flame.
