- THE 1,2-FLUORINE ATOM MIGRATION IN THE EPOXIDE OF 1,1-DICHLORODIFLUOROETHENE. THE INFRARED SPECTRUM OF DICHLOROFLUOROACETYL FLUORIDE
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The epoxide of 1,1-dichlorodifluoroethene, , and chlorodifluoroacetyl chloride, CF2ClC(O)Cl, were the principle products of the gas-phase thermal reaction of NO2 with 1,1-dichlorodifluoroethene, CF2CCl2, in presence of O2 at 257.3 K and 300.2 deg K.Five other products: COF2, COCl2, O2NCF2C(O)Cl, CF2ClCCl2NO2 and CF2ClCCl2O2NO2 were also formed in minor amounts of traces, depending on the relation between NO2, CF2Cl2 and O2.The initial pressure of NO2 was varied between 0.7 and 4.7 torr, that of CF2CCl2 between 18.4 and 81.9 torr, and that of O2 between 50.4and 696.3 torr.The isomerisation of to CF2ClC(O)Cl was never observed, but, in the presence of mercury vapour, the rearrangement of to CFCl2C(O)F occured, involving the unexpected 1,2-migration of a fluorine atom.The infrared spectrum of CFCl2C(O)F is given.The elementary reactions sequence is proposed to explain the formation of CF2C(O)Cl and .
- Czarnowski, Joanna
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- The Thermal Gas-Phase Reaction of NO2 with 1,1-Dichlorodifluoroethane, CF2CCl2 in the Presence of O2
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The gas-phase reaction of NO2 with CF3CCl2 in the presence of O2 has been studied at 257.3 and 300.2 K./ The initial pressure of NO2 was varied between 0.7 and 4.7 torr, that of CF3CCl2 between 18.4 and 81.9 torr and that of O2 between 50.4 and 696.3 torr.Several experiments were made in the presence of N2 varying its pressure between 135 and 394 torr.Seven products were formed: COF2, COCl2, CF2ClC(O)Cl, , O2NCF2C(O)Cl, CF2ClCCl2NO2 and CF2ClCCL2O2NO2.The reaction was a homogeneous chain reaction, whose rate and distribution of the products depended on the relation between NO2, CF2CCl2 and O2 and also on the total presure.The following mechanism, where E = CF2CCl2, R' = O2NCF2CCl2, R'' = CF2C;CCl2, R = R' or R'' and M = effective pressure, explains the experimental results 1.) NO2 + E = R', 2.) R' + O2 + M = R'O2 + M 3.) 2 R'O2 = 2 R'O + O2, 4.) R'O = O2NCF2C(O)Cl + Cl, 5.) Cl + E = R'' 6.) R'' + NO2 + M = R''NO2 + M, 7.) R'' + O2 + M = R''O2 + M, 8.) R''O2 + NO2 + M = R''O2NO2 + M, 9.) R''O2NO2 = R''O2 + NO2, 10.) 2 R''O2 = 2 R''O + O2, 11.) R''O = CF2ClC(O)Cl + Cl, 12.) RO2 + E = RO2(E), 13.) RO2(E) = RO + ,14.) RO2(E) + O2 + M = RO2(E)O2 + M, 15.) 2 RO2(E)O2 = 2 RO2(E)O + O2, 16.) RO2(E)O = RO + COF2 + CLCl2. At room temperature the value of 1.3 +/- 0.2*10-4 S-1 was obtained for K9.
- Czarnowski, Joanna
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- Kinetics and Mechanism of the Thermal Reaction between Trifluoromethylhypofluorite and 1,1-Dichlorodifluoroethylene
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The thermal addition of CF3OF to CF2CCl2 has been studied between -7.0 and 29.7 deg C.The pressure of CF3OF was varied between 6.4 and 196.7 Torr and that of CF2CCl2 between 5.4 and 203 Torr.CF3CCl2F, CF3O(CF2CCl2)F and CF3O(CF2CCl2)iOCF3, where i = 2,3. . .n, were the products.Above 110 Torr of olefin, non-volatile condensate appeared.The reaction was homogeneous and not affected by the total pressure or the presence of an inert gas.Introducing a few Torr of O2 to the reaction system an instantaneous oxidation of CF2CCl2 to CF2ClC(O)Cl occurred.Higher amounts of O2 led to explosion with conversion of both reactant molecules.The basic steps of the reaction were: generation of radicals CF3O. and CF3CCl2. in the bimolecular process between CF3OF and CF2CCl2 (rate constant k1), generation of telomeric radicals by addition of CF3O. to CF2CCl2, abstraction of fluorine atoms from CF3OF by CF3CCl2. and by CF3O(CF2CCl2). (rate constant k4), chain propagation by further successive addition of telomeric radicals to another molecule of olefin (k5) and recombination of telomeric radicals.The following values of the rate constants were obtained: k1 = (5.0+/-1.0)106exp(-9.7+/-0.9 kcal*mol-1/RT)l*mol-1s-1, k4 = (2.6+/-0.5)107exp(-3.1+/-0.6 kcal*mol-1/RT)l*mol-1s-1, k5 = (1.7+/-0.4)105exp(-2.5+/-0.5 kcal*mol-1/RT)l*mol-1s-1. - Keywords: CF3OF, thermal reaction with CCl2CF2 / CCl2CF2, thermal reaction with CF3OF / Trifluoromethylhypofluorite, addition to 1,1-dichlorodifluoroethylene / 1,1-Dichlorodifluoroethylene, reaction with trifluoromethylhypofluorite
- Santos Afonso, M. dos,Czarnowski, J.
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