| Poly ionic liquids which commonly referred as the polymer with one or more ionic liquids grafted on the repeating units have both the advantages of polymer and ionic liquids. The great features such as low glass transition temperature, tolerance of moisture, electron conducting, versatile structures transformation, modification and processing have made poly ionic liquids as promising materials in different fields such as material science, electrochemistry, analytical chemistry, biotechnology, energy, catalysis and surface science. HCCP is an inorganic cyclic compound with active P-Cl bond which can react with functional groups such as-OH,-NH2 and-COOH. Herein, the poly ionic liquid micro particles were prepared from polyphosphazene composed of hydroxyl group functionalized ionic liquid and multi-hydroxyl monomers. The microparticles have been successfully used as support for nano-Pd catalyst and the activity was tested with Suzuki coupling reactions.Two major parts have been discussed in this dissertation.(1) Micro/nano materials of poly ionic liquids was synthesized by reaction of [C2OHMIM]BF4, HCCP, BPS and triethylamine or pyridine as acid-acceptors in organic solvent with aid of ultrasound. The above synthesized polyphosphazene materials were fully characterized by SEM, IR, TGA and solid state 31 P NMR. The dependence of ionic liquids polymer structure and morphology on the solvent polarity, acid-acceptors and the proportion of substrates which were also studied and found to be depended on those variables. Based on these studies, we chose the PIL whose substrates' mole ratio was 1:1.5:1.25 as the support for Pd nanparticles; first the poly ionic liquids were mixed with H2 Pd Cl4 under vigorous stirring, then followed by reduction of Pd2+ to Pd0 with Na BH4 and drying under vacuum to obtain the desired catalyst Pd@PIL. The catalyst was also characterized by transmission electron micro-scopy(TEM), the diameter of palladium nanoparticles which were well dispersed was in the range 4~6 nm. The loading amount of palladium was 0.6 wt % as determined by inductively coupled plasma atomic emission spectroscopy(ICP-AES), and from the XPS spectrum, we could know two kinds of valences in the Pd nanoparticles.(2) The synthesized catalyst was then applied in the Suzuki coupling reactions to test its activity. The catalytic activities of PIL@Pd under different conditions were evaluated in the model reaction of iodobenzene with phenylboronic acid. After studing, the optimized conditions for Suzuki coupling reaction were established as follows: 0.05 mol % Pd in PIL@Pd as catalyst, ethanol-water(2:1, v/v) as solvent, K2CO3 as base, and reaction at 70 ?. Expanding of substrate reveal the order of activity is iodinebenzen > bromobenzen > chlorobenzen. Iodinebenzen with either electron withdrawing groups or electron repulsion groups react well with high yields. And p-methanylbenzylbormic acid has the same yield with benzylbormic acid. The recycle of the catalyst were also tested that after 5 times the activity drops slightly.In summary, novel polyphosphazine microsphere containing ionic liquid and as support for Pd nanoparticles were parepared, and the preparation condition was optimized. The catalyze activity of PIL@Pd was also tested with Suzuki reaction. |
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