多齿胺磁性微球的制备及应用

利用传统的共沉淀法合成纳米级磁性Fe₃O₄，并用油酸和十二烷基磺酸钠双层表面活性剂对其进行改性，制备出稳定性好，能够很好的分散到极性溶剂中的磁流体。以磁流体为种子，通过乳液聚合方法以甲基丙烯酸甲酯（MMA）和三羟甲基丙烷三丙烯酸酯(TMPTA)为原料进行交联共聚得到了表面带双键的磁性微球，再利用二乙烯三胺（DETA）与磁性微球表面的双键发生迈克尔加成反应使其氨基化，最后用丙烯酸正丁酯(BA)与DETA改性磁性微球表面氨基反应得到多齿胺配体。通过FTIR对其结构进行了表征，元素分析测得其含氮量约为1.0mmol/g。进一步将此种配体与CuCl配位并多次重复应用于催化CCl₄与MMA及三氯乙酸甲酯与苯乙烯（St）的原子转移自由基加成（ATRA）反应，通过气相色谱法测定了原料的转化率随时间变化。结果表明：在催化CCl₄与MMA和三氯乙酸甲酯与St的ATRA反应中，此种配体至少可以重复使用5次，且第一次转化率在40h内可达到80%以上，第5次时仍可达到35%以上。

Preparation and application of magnetic microspheres modified with multidentate amines

Fe3O4 magnetic nanoparticles have been synthesized by chemical co-precipitation and modified by a bilayer of oleic acid and sodium dodecyl sulfonate surfactants.The stability of the resulting magnetic fluid was very good and it could be well dispersed in polar solvents.The magnetic fluid was used as a seed to carry out the cross-linking copolymerization of methyl methacrylate(MMA) and trihydroxymethyl propyl triacrylate(TMPTA) through emulsion polymerization,affording magnetic microspheres with CC double bonds on the surface.Surface amidation of the magnetic microspheres was effected by a Michael addition reaction of the double bonds with diethylenetriamine(DETA).The multidentate amine-modified magnetic microspheres were finally obtained by reaction of the amino groups on the surface of the DETA-modified magnetic microspheres with the CC double bond of butyl acrylate(BA).Their chemical structure was confirmed by infrared spectroscopy(FTIR) and elemental analysis(EA),which gave a nitrogen content of 1.0mmol/g.The multidentate amine-modified magnetic microspheres were used as a ligand for CuCl and the resulting material used repeatedly to catalyze the atom transfer radical addition(ATRA) reactions of carbon tetrachloride(CCl4) with methyl methacrylate,and methyl trichloroacetate with styrene(St).The conversion in these reactions was determined by gas chromatography.The results indicated that the ligand can be used five times in the ATRA reaction of CCl4 with MMA,and in the reaction of methyl trichloroacetate with St,with the conversion for the first use reaching above 80% in 40 hours,and still remaining above 35% when the catalyst was used for the fifth time.