The kinetics and mechanism of the reaction of fluorine with CC1,F have been investigated in a static system ovcr the temperature range 491-598 K. The reaction was at least partly heterogeneous, independent of surface area to volume ratio, independent of diluent and uninhibited by either oxygen or chlorine monofluoride. The rate equation had the form : -d[CCI,F]/dt = k[F2]*[CC13F]. The rate constants were reproducible using different Pyrex reaction vessels and fitted the Arrhenius equation : log k(l.* molf s-l) = (6.77k0.10) -(19 250*240)/2.303 RT,A full mechanism is presented which, by using steady-state assumptions, agrees with the experimentally derived rate equation.

The rates of the hydrogen abstraction reactions of fluorine atoms with hydrogen, four alkanes and methyl chloride were measured in the gas phase using a competitive technique. The compounds were arranged in the following series in which adjacent pairs were competed for fluorine :(i> 332, CH4, C2H6, H2 (ii) CH3CI, C2Hs, C3Hs, CH3CI. New values of the activation energy for CH, and C2H6 of 1850f230 and 480f20 cal mol-I respectively have been determined which are free from self-heating crrors and are internally consistent when calculated from different competitive routes. A value of 2470&-270calmol-' for H, has been similarly obtained, which differs from previously reported values based on erroneous values for methane and ethane.

The rates of the hydrogen abstraction rections of fluorine atoms with five halomethanes and two alkanes in the gas phase were studied using competitive methods. The main competitors were arranged in the following series in which adjacent pairs were fluorinated competitively :

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