Fig. 6. Pathways CF3I reacts with the free radicals in fire flame.
When OH radical and CF3I approach each other, OH radical interacts with different atoms of the CF3I molecule in the reaction to form various possible products. As the first reaction step, the O atom of the OH can directly absorb the F atoms of CF3I molecule through the transition state TSb1 to form CF2I· + FOH (P4), with the barrier height of 64.806 kcal·mol−1. When the O atom of the OH attacks the C atom of CF3I, CF3OH + I (P5) may be formed through the transition state TSb2. In the process of reaction, O atom of OH attacks C atom of CF3I, causing it to get rid of the I atom, and the energy barrier is 41.497 kcal·mol−1. The last reaction step between CF3I and OH radical is the most likely to occur, with no intermediate transition state. CF3I directly deatoms I to generate CF3· + HIO (P7) with a small energy barrier of 8.267 kcal·mol−1. According to the above calculation results, the potential energy curve of the reaction path between CF3I and OH radical is shown in Fig.7 . The results show that in the CF3I + OH reaction, the I atom extraction channel may be dominant from the perspective of kinetics, and CF3I is more likely to generate CF3 fire-extinguishing radical.