Preparation And Applycation Of Silica/Magnetic Supported Branch Phosphine In Catalytic Reaction Of Carbon Dioxid

Recently, dendrimeric supported catalysts, which combine advantage of homogeneous and heterogeneous catalysts in some degree, are becoming to be a hot area in a catalytic field. In this paper silica and magnetic supported branch phosphine metal complexes were prepared, and the catalytic properties in the hydrogenation of carbon dioxide were evaluated.A series of 1.0⁶.0 G dendrimers (poly-amino-amide; PAMAM) modified silica have been synthesized by divergent method with modified silica gel as core. The structure of PAMAM/SiO₂ has been characterized by terminal amine analysis, TG and IR. The supported phosphines were obtained by the reaction of [Ph₂P (CH₂OH)₂]⁺Cl^-with the amine on the sphere of PAMAM/SiO₂. The combination of silica supported dendrimeric phosphine with RuCl3 affords high catalytic activity (TOF, 4195) for the hydrogenation of CO₂ in the presence of morphine. Moreover, the recyclability of catalyst was also explored.Magnetic nano particle was synthesized by co-precipitation method, magnetic supported dendrimeric Fe₃O₄-PAMAM was synthesized by divergent method through the reaction of amine on the sphere of modified magnetic Fe O with acrylate and diamine. The supported phosphine of Fe₃O₄ -PAMAM-PPh ,Fe₃O₄-PAMAM-NHCH2PhPPh₂ were obtained by the reaction of the amine of end group of support with [Ph₂P(CH₂OH)₂]⁺Cl^-,diphenylphosphinyl benzenaldehyde (DPPde). The obtained phosphine was combined with RuCl3 to form a catalyst in situ, and the activity of the catalytic system in hydrogenation of carbon dioxide was evaluated. Compared with DPPde as phosphine resource the catalytic system produced by [Ph₂P(CH₂OH)₂]⁺Cl^- afforded higher activity.