Figure 7 Potential energy diagram of the reactions between R123 and H·, OH·.
The analysis of the reaction of fire extinguishing agent and its decomposition derivatives with H· and OH· is also an important aspect of revealing the fire extinguishing mechanism of fire extinguishing agent, hence the reactions of R123 with H· and OH· radicals are theoretically simulated in detail (Figure 7). OH· radical interacts with different atoms in R123 to form different products. The C-Cl bond homolysis reaction occurs in path 9, the OH· can absorb an Cl atom of R123 to generate CF3CHCl· and HClO through the TSb1, overcoming the energy barrier of 117.7 kj·mol-1. The C-F bond homolysis reaction occurs in path 10, R123 interacts with OH· through abstraction reaction to generate CF2CHCl2· and HFO, the reaction to occur requires the absorption of about 296.8 kj·mol-1 energy. Furthermore, there are two paths about substitution reaction. In path 11 and path 12, OH· radical can replace the Cl· and F· atoms in R123 to form CF3CHClOH and CF2OHCHCl2, respectively, the products are generated via the TS of TSb3 and TSb4 with the energy barriers of 234.5 and 802.3 kj·mol-1, the Cl· and F· atoms will be very easy to react with free radicals such as H· and OH·, reducing the chain reactions in combustion. For the reaction of R123 with H·, two abstraction reaction paths are theoretically exhibited in Figure 7. P13 (path 13) and P14 (path 14) are generated via TSc1 and TSc2 by conquering the energy barriers of 136.9 and 44.6 kj·mol-1 separately. According to the energy barrier, it can be seen that P13 is more likely to generate than P14. And through further simulation calculations it is found that CF3CHCl· can generate CF3· via C-C bond fracture, the specific reaction is shown in path 15 and path 16. The generation of CF3· promotes the chemical action of R123 in fire extinguishing and also accelerates the speed of fire extinguishing.