| 磁性固体超强酸SO42-/ZrO2-Al2O3-Fe3O4的制备与性能研究 |
| Preparation and Properties of Magnetic Solid Superacid SO42-/ZrO2-Al2O3-Fe3O4 |
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| 摘要: 利用化学共沉淀法将磁性基质与固体酸组装制备磁性纳米固体超强酸催化剂，利用XRD、Raman、TG-DSC、M?ssbauer、TEM、HRTEM等手段对样品性质进行表征。结果表明：磁性基质的引入赋予固体超强酸以超顺磁性；Fe3O4、Al2O3粒子弥散在ZrO2基质中，烧结过程中阻碍了扩散传质的进行以及晶界移动，抑制了ZrO2晶体生长，稳定了四方晶相(T-ZrO2)；样品粒径分布集中，平均约为32 nm；HRTEM显示T-ZrO2晶体生长取向于(101)方向，晶面间距d(101)=0.29 nm；Hammett指示剂法测得经600 ℃焙烧后产物的酸强度Ho＜-13.8，酸强度大于浓硫酸(Ho=-11.93)。以柠檬酸三丁酯的合成作为磁性固体超强酸SO42-/ZrO2-Al2O3-Fe3O4催化剂的探针反应，结果表明外磁场的引入提高了柠檬酸的转化率。 |
| 关键词: 化学共沉淀法 固体酸 超顺磁性 酯化反应 |
| 基金项目: |
| Abstract: Magnetic SO42-/ZrO2-Al2O3-Fe3O4 solid superacids were prepared by introduction of Al2O3 and magnetic substrates via the chemical co-precipitation method. The physicochemical properties of the materials were characterized by XRD, Raman, TG-DSC, M?ssbauer, TEM, and HRTEM. The results indicate that the introduction of magnetic substrates endows the material with the superparamagnetism property. Additionally, the introduced Al2O3 and Fe3O4 are finely dispersed throughout the matrix of the ZrO2, which plays an important role in hampering the development of diffusion mass transfer and movement of the grain boundaries. Furthermore, the introduction of Al2O3 and Fe3O4 also delays the phase transition from tetragonal zirconia to monoclinic zirconia, which improves the sintering temperature. The TEM image indicates that the samples show well-defined crystallographic faces with average size of 32 nm. The HRTEM shows that the interplanar spacing is d(101)=0.29 nm. The sample calcined at 600 ℃ is estimated to have Ho＜-13.8, which is stronger than that of H2SO4 (Ho=-11.93). Furthermore, the introduction of magnetic field improves the conversion of citric acid in the synthesis of tributyl citrate over magnetic SO42-/ZrO2-Al2O3-Fe3O4 solid superacids. |
| Keywords: chemical co-precipitation solid acid superparamagnetism esterification reaction |
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| 摘要点击次数: 1438 |
| 全文下载次数: 1894 |
| 王君,范美青,杨飘萍,景晓燕,张密林.磁性固体超强酸SO42-/ZrO2-Al2O3-Fe3O4的制备与性能研究[J].无机化学学报,2007,23(7):1137-1142. |
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