The gas‐phase kinetics of the reaction of 1,1,1‐trifluoroethyl iodine with HI: The CI bond dissocation energy in 2,2,2‐trifluoroethyl iodide

Abstract

Abstract The kinetics of the gas‐phase reaction of 2,2,2‐trifluoroethyl iodide with hydrogen iodide has been studied over the temperature range of 525°K to 602°K and a tenfold variation in the ratio of CF 3 CH 2 I/HI. The experimental results are in good agreement with the expected free radical‐mechanism: An analysis of the kinetic data yield: where θ =2.303 RT in kcal/mol. If these results are combined with the assumption that E 2 = 0 ± 1 kcal/mol, then one obtains DH (CF 3 CH 2 I) = 56.3 kcal/mol. This result may be compared with DH (CH 3 CH 2 I) = 52.9 kcal/mol and suggests that substitution of three fluorines for hydrogen in the beta position strengthens the CI bond slightly.