负载过渡金属磁性催化剂的制备及Heck反应性能

发布时间：2018-04-27 10:41

  本文选题：磁性纳米材料 + 过渡金属　； 参考：《北京化工大学》2016年硕士论文

【摘要】：磁性纳米级催化剂不仅具备纳米粒子的结构与性能,还有磁性,使得催化剂具有高催化性能,且可回收再利用；贵金属Pd价格高,而过渡金属成本低、无毒,因此,制备出绿色环保、经济、活性高的催化剂已成为人们关注的热点。此论文所使用的催化剂颗粒尺度为纳米级,以磁性Fe304为磁核,以m-Si02@si02@Fe3O4为载体,为了实现对活性组分的良好负载,对二氧化硅层做了氨基修饰——m-siO2-NH2@SiO2@Fe3O4,最后成功制备了Cu/m-SiO2@SiO2@Fe3O4、Cu-Pd/m-SiO2@SiO2@Fe3O4、Co-Pd/m-SiO2@ SiO2@Fe3O4这三种催化剂。采用了XRD、FT-IR及TEM分析方法对三种催化剂进行了结构表征。本文选择碘苯和丙烯酸甲酯为Heck反应模型研究催化剂的催化性能及重复使用性能。取得的结果如下：(1)制备出了粒子大小约为110nm、分散性能好的纳米级Fe304微球；氨基修饰后的载体m-SiO2-NH2@SiO2@Fe3O4负载金属更加均匀,不会发生团聚现象,所负载的Cu金属颗粒直径为2-4nm；(2)Cu/m-SiO2@SiO2@Fe3O4的催化性能良好,最佳的反应条件为：Cu的负载量为17.5wt%时,碘苯：丙烯酸甲酯：碱为1：1.5：1.2(摩尔比),以DMF为溶剂,三乙胺为碱源,140℃下,反应18h,反应物碘苯的转化率为55.16%。催化剂具有良好的回收使用性能,可重复利用3次；(3)Cu-Pd/m-SiO2@SiO2@Fe3O4的催化性能良好,最佳的反应条件为：Pd的负载量为0.5wt%,Cu的负载量为4wt%时,碘苯：丙烯酸甲酯：碱(摩尔比)为1：1.5：1.2,DMF为溶剂,三乙胺为碱源,120℃下,反应3h,碘苯的转化率为99.55%,可重复利用5次；(4)Co-Pd/m-SiO2@SiO2@Fe3O4的催化性能良好,最佳的反应条件为：Pd的负载量为0.5wt%,Co的负载量为6wt%时,碘苯：丙烯酸甲酯：碱(摩尔比)为1：1.5：1.2时,NMP为溶剂,三乙胺为碱源,120℃下,反应3h,碘苯的转化率为99.68%,可重复利用5次。
[Abstract]:Magnetic nanocrystalline catalysts not only possess the structure and properties of nanoparticles, but also have magnetic properties, which make the catalysts have high catalytic performance and can be recycled and reused. The price of noble metal PD is high, while the cost of transition metal is low, and the transition metal is non-toxic. The preparation of green, economical and highly active catalysts has become the focus of attention. The catalyst used in this paper is nanometer scale, magnetic Fe304 as magnetic nucleus, m-Si02@si02@Fe3O4 as carrier, in order to achieve good loading of active components. The SiO2 layer was modified with amino groups, m-siO2-NH2AlSiO2SiO2Fe3O4. Finally, three kinds of catalysts, Cu/ m-SiO2SiO2Fe3O4, Cu-PdR / m-SiO2SiO2Fe3O4 / Co-PdR / m-SiO2 @ SiO2@Fe3O4 were successfully prepared. The structure of the three catalysts was characterized by XRD- FT-IR and TEM. In this paper, Iodobenzene and methyl acrylate were selected as Heck reaction models to study the catalytic performance and reusability of the catalyst. The results obtained are as follows: (1) Fe304 microspheres with a particle size of 110 nm and good dispersion properties were prepared. The modified carrier m-SiO2-NH2@SiO2@Fe3O4 supported the metal more evenly without agglomeration. The supported Cu metal particle diameter is 2-4 nm ~ (-1) N ~ (-1) N ~ (2) O ~ (2 +) Cu / m -SiO _ (2) O _ (2) @ Sio _ (2) Fe _ 3O _ (4). The optimum reaction conditions are as follows: when the loading amount of 1: Cu is 17.5 wt%, the molar ratio of iodobenzene: methyl acrylate to alkali is 1. 5: 1.2 (mole ratio, DMF as solvent, triethylamine as alkali source, 140 鈩，

本文编号：1810399