物理化学学报 >> 2010, Vol. 26 >> Issue (07): 1860-1866.doi: 10.3866/PKU.WHXB20100707

催化和表面结构 上一篇    下一篇

超顺磁性介孔纳米颗粒嫁接肟Pd环络合物对Heck反应的催化活性

沈彬, 王永安, 王志飞, 张玲   

  1. 东南大学化学化工学院, 南京 211189
  • 收稿日期:2010-01-28 修回日期:2010-03-23 发布日期:2010-07-02
  • 通讯作者: 沈彬 E-mail:binshen2000@hotmail.com

Catalytic Activity of an Oxime Carbapalladacycle Complex Grafted onto Superparamagnetically Mesoporous Nanoparticles for the Heck Reaction

SHEN Bin, WANG Yong-An, WANG Zhi-Fei, ZHANG Ling   

  1. School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, P. R. China
  • Received:2010-01-28 Revised:2010-03-23 Published:2010-07-02
  • Contact: SHEN Bin E-mail:binshen2000@hotmail.com

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摘要：

采用溶胶-凝胶法制备出介孔二氧化硅包裹四氧化三铁纳米复合颗粒, 在其表面修饰巯基, 并以此为载体通过—SCH2—化学键嫁接长链的肟钯环络合物. 利用透射电镜(TEM)、高分辨透射电镜(HRTEM)、傅里叶变换红外(FT-IR)光谱、N2吸附-脱附、X光电子能谱(XPS)、振动样品磁强计(VSM)等手段对催化剂进行表征, 通过Heck反应对催化剂的活性进行评价. 实验结果表明: 所制备的磁性颗粒直径约为150 nm, 比表面积为287.0 m2·g-1, 且具有大小为3.5 nm呈不规则的孔道结构, 整个催化剂呈现超顺磁性. 对于碘代苯与丙烯酸乙酯之间的Heck反应, 2.5 h后碘代苯的转化率可达到99%, 催化剂在重复使用6次后能保持很高的催化活性(碘代苯转化率为95%). 催化剂可稳定分散于反应体系中, 并可在外磁场作用下快速与反应体系分离.

关键词: 溶胶-凝胶法, 超顺磁性, 介孔材料, 肟钯环络合物, 负载型催化剂, Heck反应

Abstract:

A mesoporous SiO2@Fe3O4 nanocomposite was prepared by the sol-gel method. The nanocomposite was modified with a thiol and then a long carbon chain oxime carbapalladacycle complex as grafted by a—SCH2— linkage. The catalyst was characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR) spectroscopy, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and vibration samplemagnetometry (VSM). Its catalytic activity for the Heck coupling reaction was measured. The BET surface area of the support with a diameter of 150 nm was about 287.0 m2·g-1 and the average pore size was about 3.5 nm. The catalyst had superparamagnetic properties. In the Heck reaction of iodobenzene with ethyl acrylate, a high conversation of 99%was obtained after 2.5 h. The catalyst was reused 6 times without significant loss of activity (95%after the sixth run). The catalyst was easily dispersed in the reaction mixture and was separated swiftly by an added magnetic field.

Key words: Sol-gel method, Superparamagnetic, Mesoporous, Oxime carbapalladacycle, Supported catalyst, Heck reaction