SUBSTITUENT EFFECTS ON THE DISPROPORTIONATION-COMBINATION RATE-CONSTANT RATIOS FOR GAS-PHASE HALOCARBON RADICALS .3. REACTIONS OF CF3+CF3CH2CHCF3 AND CF3CH2CHCF3+CF3CH2CHCF3

Disproportionation/combination rate constant ratios, k(d)/k(c), for th e reactive collision between CF(3)CH(2)CHX + CF3 radicals and between CF(3)CH(2)CHX + CF(3)CH(2)CHX radicals have been measured for X = CF3. The k(d)/k(c) = 0.066 +/- 0.013 when H is transferred to the CF3 radi cal and 0.125 +/- 0.025 for H transfer to the CF3CH2CHCF3 radical. Com parison of these results with previous work shows that X = CF3 increas es the k(c)/k(c)'s relative to X = Cl or H. The effect of the CF3 subs tituent on the disproportionation rate is discussed. (C) 1996 John Wil ey & Sons, Inc.