Abstract: | The kinetics of the gas-phase reaction of CH3F with I2 have been studied spectrophotometrically from 629 to 710 K, and were determined to be consistent with the following mechanism: (1) A least-squares analysis of the kinetic data taken in the initial stages of reaction resulted in where θ = 4.575T/1000 kcal/mol. The errors represent one standard deviation. The experimental activation energy E4 = 30.8 ± 0.2 kcal/mol was combined with the assumption E3 = 1 ± 1 kcal/mol and estimated heat capacities to obtain The enthalpy change at 298 K was combined with selected thermochemical data to derive The kinetic studies of ?HF2 and CH2F2 have been reevaluated to yield These results are combined with literature data to yield the C? H, C? F, and C? Cl bond dissociation energies in their respective fluoromethanes, and the effect of α-fluorine substitution is discussed. |