有机氯代污染物催化加氢脱氯中溶剂协同供氢与降解机理

Liquid-phase catalytic hydrodechlorination (HDCl) is a promising technology for the disposal of persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs). And solvent systems are considerably important factors to influence the liquid-phase HDC reaction. In the liquid-phase catalytic HDCl of PCBs, it was found that H2O could provide active hydrogen. In order to investigate the mechanism of this phenomenon, 4-chlorobiphenyl and 4-chlorophenol will be selected as model compounds in the catalytic HDCl of chlorinated organic compounds. Using hydrogen-deuterium isotope exchange, along with analyses and characterization such as mass spectrum (MS)and nuclear magnetic resonance (NMR), the effects of different kinds of solvents on catalytic HDCl reactions will be studied to investigate the relationships among the solvents, active hydrogen, the catalyst and the reactants, which can provide some data to explain the ability, rules and mechnisms of active hydrogen from the solvents. Additionally, the mechnism of active hydrogen from water will also be studied in organic-water biphase medium in the HDCl. On the basis of these studies, the mechnism of catalytic HDCl of PCBs in aqueous solutions will be investagated. In the end, an effective method using the catalytic hydrotreatment will be developed to degrade PCBs.

液相催化加氢脱氯是处理PCBs等POPs的有效降解方法，溶剂体系对催化加氢脱氯有着重要的影响。针对PCBs在液相催化加氢降解过程中水能够协同供氢的这一新发现，以4-氯联苯和4-氯苯酚作为代表反应模型，以Pd/C为催化剂，开展液相体系中PCBs等有机氯代物催化加氢过程中溶剂协同供氢和加氢降解机制的研究。通过研究不同类型溶剂与加氢脱氯反应的效应关系，利用同位素H/D交换实验，结合质谱、核磁共振等仪器分析和表征，认识溶剂体系与催化剂、氢源、反应物之间的相互作用，阐明溶剂供氢性能、规律和机制，揭示有机-水两相体系中水协同供氢机理，提出PCBs等有机氯代物在含水体系中加氢降解过程和机制，在此基础上，针对PCBs等POPs建立高效的液相催化加氢降解体系。

多氯联苯（PCBs）、滴滴涕（DDT）等是一类持久性有机污染物。氯原子的存在是导致其具有持久性、生物蓄积性以及高毒性重要原因。催化还原脱氯是降解PCBs等POPs的有效方法，利用具有强还原能力的活性氢取代氯原子，达到降低和消除PCBs等POPs高毒性和高稳定性的目的。.项目针对PCBs在液相催化加氢降解过程中水协同供氢这一发现，以4-氯联苯、4-氯苯酚作为模型化合物，以Pd/C 、RaneyNi等作为催化剂，开展液相体系中PCBs、氯酚等有机氯代物催化加氢脱氯过程中溶剂效应、协同供氢和加氢降解机制的研究。通过研究不同类型溶剂与催化加氢脱氯反应的效应关系，认识了溶剂与催化剂、氢源之间的相互作用与规律，阐明了醇类质子溶剂供氢性能、规律和可能机制，揭示了水协同供氢的可能机理，提出PCBs等有机氯代污染物在含水体系中高效加氢脱氯的加氢降解过程和机制，建立了醇-水均相体系中POPs高效加氢降解体系。同时，研究和比较了醇水体系中Pd/C、Raney Ni催化下卤代苯和卤代苯酚中碳卤键C-F、C-Cl、C-Br、C-I加氢反应性和规律。在此基础上，针对氯酚、废电容器油、DDT重污染土壤等工业危险废物和库存POPs，建立了温和条件下(30 ℃ and 1 atm)高浓度有机氯的液相高效催化加氢降解体系、方法和技术。