Preparation And Catalytic Properties For Heck Reaction Of Regular Polymer Supported Palladium Catalysts

Palladium-catalyzed Heck reaction gradually become an effective tool in modern organic synthesis inrecent years and has been widely applied in medicine, pesticides, luminescent materials and polymersynthesis. The reaction is normally carried out in homogeneous catalysis system with Pd（OAc）₂and PdCl₂as catalyst. Although these catalyst have high catalytic activity and selectivity; However, this kind ofcatalysts suffer from severe problems related with the recovery, separation and unstable in high temperatureetc, which have so far precluded the widespread industrial application. These problems can be overcome bythe use of heterogeneous catalyst. The polymer-supported palladium catalyst with the uniform morphologyat micron or submicron size having high selectivity and activity are currently attracting wide concernbecause they can be easily separated and recycled. Thus the following researches are conducted with thisthesis.1. Polyphenol microspheres and poly （p-aminophenol） microspheres were synthesized by enzymecatalytic template polymerization. The polyphenol microspheres and poly（p-aminophenol） microspheressupported palladium complexes were synthesized with simple method and characterized by IR, XRD, XPS,SEM, TG and DTA etc. SEM confirms that two kinds of catalyst are good monodispersity. The average sizeof polyphenol microsphere supported palladium catalyst and poly（p-aminophenol） microsphere supportedpalladium catalyst is about0.5μm and2.0μm respectively. Thermal analysis shows that both polyphenolmicrosphere supported palladium complexes and poly （p-aminophenol） microsphere supported palladiumcomplexes have high thermal stability. Two kinds of catalyst are effectively for Heck reactions of arylhalide with acrylic acid、styrene. For comparison, the catalytic performance of poly（p-aminophenol）microsphere supported palladium complexes is much more efficient than polyphenol microspheresupported palladium complexes under identical conditions. Two kinds of catalyst can be easily recoveredfrom the reaction mixture and reused for several times.2. A polyaniline/multiwall carbon nanotubes nanocomposite was synthesized via simple reactions. Anovel catalyst was obtained through the interaction of polyaniline/multiwall carbon nanotubesnanocomposite with PdCl2. The novel catalyst was characterized by IR、XRD、XPS、TEM、TG. TEMconfirms that a core shell structure of MWCNTs at the center can be seen clearly and the diameter of MWCNTs–PANI nanotubes was about80–140nm. The average size of palladium nanoparticles is in therange of4–9nm. It remains high catalytic for Heck reaction of iodobenzene with acrylic acid even at60℃and the yields are higher than60%. The novel catalyst show high catalytic activity for Heck reaction ofdifferent substrate. The complexes can be easily recovered and reused for several times.