Kinetic study for the production mechanism of halo-dibenzo-p-dioxin

点击翻译按钮获取中文摘要

In order to confirm that the dibenzo-p-dioxin production channel in combustion is 2C_6H_5O→C_6H_4O_2C_6H_4+2H, high temperature reactions of phenoxy radicals (C_6H_5O) were investigated over the temperature range 1250 - 1700 K using shock-tube techniques. Methoxybenzene (C_6H_5OCH_3) and trifluromethoxybenzene (C_6H_5OCF_3) were used as sources of C_6H_5O radicals. By comparing the experimental results with those by computer simulations, high temperature reactions of C_6H_5O radicals including the dibenzo-p-dioxin production channel were discussed. Reaction products of C_6H_5O decomposition were also analyzed with gas chromatography by sampling the final products behind the reflected shock of C_6H_5OCH_3 and C_6H_5OCF_3 diluted with Ar mixtures. We found that not only the linear hydrocarbons but also aromatic compounds such as phenol were produced behind the shock. However the dibenzo-p-dioxin was not detected as the final products behind the shockwaves of C_6H_5OCH_3 and C_6H_5OCF_3 diluted with Ar mixtures. To simulate the temperature dependence of the yield of dibenzo-p-dioxin production, kinetic model for dibenzo-p-dioxin formation was proposed and compared with the experimental observations.