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.