Abstract
CCI2F2 was pulse irradiated at 921 cm-1, where a CC12 stretching mode is excited, and at 1088 cm-1, where a CF2 stretching mode is excited. Laser-induced reactions at the two frequencies are practically identical, both qualitatively and
quantitatively. Major reaction products are C1F2CCC1F2 and CCIF3 and account for ~83% of decomposition. Minor products formed initially are C1F2CCP2F and CCI3F; there was no evidence for C2F4. A reaction mechanism involving primary C-Cl bond scission is indicated. Conversion of CC12F2 per flash if) was as high as 13%; radiant energy absorbed (£abs) was as high as 107 kj/mol. The plot of In/vs. £abs-1 is linear \yith a slope of —419 kJ/mol, which is in good agreement with -£ac, for ther- mal decomposition of CC12F2. When CC12F2 is excited at 921 cm-1 in the presence of CBr2F2 (which does not absorb at 921 cm-1), the absence of organic bromochlorides from the reaction products suggests that reaction takes place in two stages: CC12F2 decomposes very quickly after excitation from a nonequilibrium molecular energy distribution, while CBr2F2 reacts thermally after V-T/R relaxation of the absorbed energy.