Hydrodehalogenation Of Doxin-like Compounds In Aqueous-organic Biphase System

Aromatic halides have been receiving increasing concern for which had a great threat to human health and could cause serious environmental pollution due to their high toxity and low degradability. The catalytic hydrodehalogenation is considered to be the most promising method for eliminating of aryl halides because of it is simple, safe and efficient. Many a researchers paid much attention to the hydrodehalogenation in both gas-phase and liquid-phase with various catalysts.In this work, the catalytic hydrodehalogenation methods of 4-bromobiphenyl, 2,4,8-trichlorodibenzofuran (2,4,8-TCDF) and polychlorinated biphenyls (PCBs) of transformer oil were examined in liquid phase under mild conditions over Pd/C catalyst. By means of studying the mechanisms of deactivation of catalyst and regulation of phase transfer agents, a technology of hydrodehalogenation of dioxin-like compounds was developed under a aqueous-organic system. High concentration of dioxins, PCBs and other POPs especially for those possess high hydrophobicity a efficient conversion were realised in this reaction system. In light of these research results, a new technology or method was proposed for eliminating large stockage of POPs in our country. Meanwhile, the effects of temperature, alkali, solvent and phase transfer agent on the dehalogenation reaction as well as hydrogenation selectivity in 2,4,8-TCDF hydrodechlorination process were investigated.4-bromobiphenyl, 2,4,8-trichlorodibenzofuran (2,4,8-TCDF) and polychlorinated biphenyls (PCBs) of transformer oil can be degradated efficiently under mild conditions in a biphase system. Alkali, solvent and phase transfer agent act as the most important factors in the hydrodehalogenation process. Additionally, temperature, type of substituent group and the ratio of aqueous/oganic solvent also affect the results greatly.