A theoretical study on decomposition of carbon tetrachloride, trichloroethylene and ethyl chloride in dry air under the influence of an electron beam

Abstract

New experimental data were published in literature regarding CCl 4 , C 2 HCl 3 and C 2 H 5 Cl decomposition in dry air under electron beam influence. Taking into account experimental data theoretical models of those species decomposition were established and computer simulations were performed by the authors of this work to find the kinetics of such processes. The results of the calculations and experimental data show that CCl 4 decomposition depends on delivered dose and initial CCl 4 concentrations. The calculation revealed that recombination of CCl + 4 and Cl − is the source of CCl 3 radicals and that reaction may have an important role in the process of CCl 4 decomposition. A theoretical model of C 2 HCl 3 decomposition in dry air under electron beam influence describes the decay of C 2 HCl 3 and the formation of several products such as Cl 2 , CCl 2 O, CO, CO 2 , HCl and C 2 HCl 3 O. The detailed comparison of experimental and theoretical data shows relatively good agreement in efficiency of C 2 HCl 3 decomposition process, but it can be achieved only with an assumption that the relation between rate constants of C 2 HCl 4 O intermediate product decomposition (C 2 HCl 3 O+Cl and COCl 2 +CHCl 2 ) should be around 20 and C 2 HCl 3 O oxidation rate should be not lower than 7.5×10 −11 cm 3 /mols. All those rate constants are not yet established experimentally. The results of the calculation of C 2 H 5 Cl decomposition and the data obtained experimentally were compared. The temperature, gas pressure, initial C 2 H 5 Cl concentration and dose range were equal in both cases. An elaborated model allow us to obtain quantitatively similar results as the experiments, but the degree of C 2 H 5 Cl decomposition for certain dose levels is significantly higher in experimental data. It is quite probable that some important processes have not been included to the theoretical model.