Journal of Physical Chemistry, Vol.98, No.41, 10568-10577, 1994
An Infrared Chemiluminescence Study of the Reactions of Hydrogen-Atoms with Cf3Ocl and Cf3O
The H atom plus CF3OCl reaction system has been used to study the primary Cl atom abstraction event and the secondary reaction between H atoms and OCF3 using infrared chemiluminescence from a flow reactor. The 300 K rate constants for the primary and secondary reactions were measured as (1.6 +/- 0.2) x 10(-11) and (1.5 +/- 0.6) x 10(-10) cm(3) molecule(-1) s(-1), respectively. The nascent vibrational distributions of HCl and HF were used to discuss the dynamics associated with the abstraction and elimination processes. The HCl vibrational distribution is inverted and resembles the distributions from abstraction of Cl atoms from other polyatomic molecules. The HF(v) distribution from the H + CF3O reaction and the DF(v) distribution from D + CF3O decline with increasing v level. Our results were compared to the HF(v) distribution produced by the O(D-1) insertion reaction into CHF3. The distributions are self-consistent, and a satisfactory general view exists for the dynamics associated with the four-centered elimination of HF from CF3OH for the 110-155 kcal mol(-1) range of energy. The energy disposal to HF resembles the results far four-centered HF elimination from CF3CH3. A laser-induced fluorescence experiment using the CF3O(($) over tilde A-($) over tilde X) transition Save a CF3O(($) over tilde A) radiative lifetime of 150 +/- 15 ns. The H f CF3O reaction is of atmospheric interest, because CF3O and CF3OH are possible products from the photooxidation of alternative fluorocarbons.
Keywords:UNIMOLECULAR ELIMINATION-REACTIONS;HALOGENATED ALKOXY RADICALS;VIBRATIONAL-ENERGY DISPOSAL;LASER FLASH-PHOTOLYSIS;RESOLVED FTIR EMISSION;FRANCK-CONDON FACTORS;RATE CONSTANTS;CHEMI-LUMINESCENCE;DIATOM REACTIONS;KINETICS