PVP-PdCl2-CuCl2/SiO2-PEG600催化芳氯化物水相脱氯研究

PVP(聚乙烯吡咯烷酮)负载双金属催化剂催化芳香氯化物脱氯已有报道1～3];利用双金属的协同作用,可以大大提高催化剂的脱氯活性和选择性4]. 但是,这些研究多是在有机相中进行的,催化剂在水相中则会降低甚至失去活性,且难以回收和重复利用. 然而,难溶于水的有毒芳香氯化物,常存在于工业或生活排放的废水中. 由于治理环境的需要,研究芳香氯化物催化水相脱氯,则是极具挑战性的课题. 本文把起相转移作用的聚乙二醇(PEG)键合到硅胶上作为固相载体,制成双负载双金属水相脱氯催化剂PVP-PdCl2-CuCl2/SiO2-PEG600,成功地用于难溶于水的芳香氯化物的水相脱氯. 研究结果表明,这种催化剂对于芳香氯化物有良好的催化脱氯性能,使用中便于分离并能重复利用. 同时,用IR,TEM和XPS等手段对催化剂进行了表征,探讨了催化剂中各组分在催化脱氯中的作用.

Study on Dechlorination of Aromatic Chlorides Catalyzed by PVP-PdCl2-CuCl2/SiO2-PEG600 in Water Phase

Based on PVP(polyvinylpyrrolidone) supported bimetallic Pd Cu and silica gel function allied by PEG 600 (polyethylene glycol, average relative molecular mass 600), a novel dually supported bimetallic catalyst, PVP PdCl 2 CuCl 2/SiO 2 PEG600, was prepared, and the bimetallic molar ratio and the pH of reaction medium had a great influence on catalytic activity of the catalyst for dechlorination of aromatic chlorides. It was shown that the catalyst had high activity and selectivity in water phase and could be easily separated and reused. The catalyst could be reused for six times with the reactant conversion over 70%. The catalyst was characterized and the effect of each component of the catalyst was discussed. The bimetallic synergic effect of Pd and Cu accelerated the dechlorination, and the coordination of PVP with metal made metal monodisperse on the catalyst surface. PEG not only was used as phase transfer catalyst, but also was coordinated with metal, making the catalyst in spherical shape and its specfic surface area increasing.