The interrelated effects of temperature and fluorine concentration on fluorine-olefin reactions have been investigated with some perhaloolefins. Reactions were carried out a t low temperatures in a new apparatus which was equipped with a novel high speed nickel gauze stirrer, gas disperser. Reproducible results were obtained with weight recoveries of 95% or better. n'ith. CF3CF=CFCF3, increasing the effective fluorine concentration greatly reduced the formation of dimer addition product relative t o simple ,addition product. Lowering the reaction temperature had a similar effect due t o reduction in the rate of the fluorine-olefin free radical initiation reaction. Related experiments with CCIF=CClF, CFz=CCIz, and CFz=CCIF, and a mixture of CF3CF=CFCF3 and CClF=CCIF, are also reported. m'ith CFz=CCIF the fluorine-olefin reaction was diffusion rate-controlled a t temperatures as low as -150'. The observed effects of reaction conditions on product composition, are shown to be consistent with the general free radical mechanism previously presented for fluorine-olefin reactions' and to provide a guide for the choice of synthesis conditions. T h e liquid phase fluorination procedure described is considered suitable for general use.
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