【作者】 薄丽丽；

【导师】 杨武；

【作者基本信息】 西北师范大学 ， 分析化学， 2005， 硕士

【摘要】 纳米材料的研究及其制备技术引起了世界各国的普遍重视,由于纳米材料的一些特殊的性能,使其在诸多领域中有着十分重要的作用。因此,开发低能耗、操作设备简单的纳米材料制备技术已成为纳米材料的研究关键之一。这样既有利于对纳米材料进行深入细致的理论研究,又有利于拓宽纳米材料的应用范围。由于纳米材料的小尺寸效应、表面效应,使其表面的原子数多、表面位能高,纳米材料在催化领域中表现出极高的催化活性。 本工作中,以硝酸盐-柠檬酸-聚乙烯醇为燃烧体系,将溶胶-凝胶技术和自蔓延低温燃烧的方法相结合来制备纳米金属氧化物粉体。同时,以所制备的纳米金属氧化物为基底合成了纳米固体超强酸。在实验中,借助差热-热重分析、X-射线粉末衍射技术、X-射线光电子能谱、透射电子显微镜、原子力显微镜、红外光谱等技术对制备的纳米金属氧化物和纳米固体超强酸进行了表征,研究了纳米固体超强酸在酯化反应中的催化活性。包括以下内容: 第一部分文 献综述 第一章 自蔓延燃烧法合成纳米材料 从燃烧法的发展历史和原理两个方面分别对高温燃烧合成技术和低温燃烧合成技术进行了介绍。 第二章 固体超强酸的研究进展 本部分从固体超强酸的提出、发展、分类方法、制备方法、酸碱理论及其在有机反应中的应用几个方面作了阐述,尤其是对酯化反应的催化活性作了重点介绍。 第二部分 实验研究 第一章 纳米稀土固体超强酸SO₄^2-/Sm₂O₃的合成、表征及催化性能的研究 第一节 利用溶胶-凝胶低温自蔓延燃烧法制备纳米Sm₂O₃ 将溶胶-凝胶法（Sol-gel）和低温燃烧技术（LCS）相结合,成功开发了一种以溶胶-凝胶为前驱体的燃烧合成新技术,制备了Sm₂O₃纳米粉体,利用XRD、TEM、AFM等方法对合成产物进行了表征,并考察了制备条件对Sm₂O₃纳米粉体尺寸和形貌的影响。 第二节 纳米固体超强酸SO₄^2-/Sm₂O₃ 的制备及表征 将所制得的纳米氧化钐在不同更多还原

【Abstract】 Nanomaterials are a new class of materials that has been making a silent revolution in the past few years. It is a foundation of the nano-technology and has aroused an extensive concern all over the world. The properties of nanomaterials show remarkable improvement or deviation from the properties exhibited by the common materials. They exhibit some special optical, magnetic, electric, or catalytic properties. These properties are attributed to the significant increase in grain boundary area due to the small grain size. Area of application that can be foreseen to benefit from the small size include quantum electronics, nonlinear optics, photonics, chemical selective sensing, and information storage and processing, adsorbents, catalysis, solar cell, magnetic recording devices, superplastic ceramics, superhard metals, metastable alloys and so on.In general, researches in nano-materials are mainly concerned with the development of methods of new syntheses and characterizations and their applications. In this thesis, sol-gel auto-combustion was employed to prepare Sm₂O₃, ZrO₂, Sni₂O₃-ZrO₂ nanoparticles and corresponding solid acid. Their structure, size and morphology were characterized by TG-DTA, XRD, XPS, TEM, AFM, IR etc.The main content is shown as following:Part One ReviewChapter One In this chapter, development and mechanism of combustion synthesis （CS）, a new method to synthesize materials, were introduced. CS consists of self-propagating high-temperature synthesis（SHS） and low-temperature combustion synthesis（LCS）. The difference and the similarity between SHS and LCS were also described.Chapter Two In this chapter, development, classification and synthesis of solid superacids were reviewed, and their applications in the organic synthesis reactions, especially in esterification were introduced as well.Part Two Experiments Chapter One Synthesis and characterization of nano-metric solid superacidSO^2-₄/Sm₂O₃ and its catalytic activity for esteriflcation. Section One Preparation and characterization of Sm₂O₃nano-powders by a sol-gel auto-combustion technique. Sm₂O₃ nano-powders were prepared by a novel sol-gel auto-combustion method, which was a low-temperature combustion synthesis procedure using sol-gel as precursors. X-ray diffraction （XRD）, transmission electron microscopy （TEM）, atomic force microscopy （AFM） were used for the sample characterization. The influences of preparation conditions on the size and morphology of the nanoparticles have been studied in detail.Section Two Preparation and characterization of SO^2-₄/Sm₂O₃ nano-powders by a sol-gel auto-combustion technique. A sort of nanometric solid super acid SO^2-₄/Sm₂O₃ was synthesized by maceration in H₂SO₄, filtration, dryness and calcination processes of substrate nanometric Sm₂O₃ The effects of preparation conditions on the catalytic activity of SO^2-₄/Sm₂O₃ were examined by the conversion of acetate acid in the esteriflcation reaction of isomyl alcohol and acetate acid. The structure of SO^2-₄/Sm₂O₃ solid super acid was analyzed by XRD, XPS and IR. In addition, TEM and AFM were also employed to measure the size and morphology of SO^2-₄/Sm₂O₃ solid super acid.Section Three Synthesis of iso-amylacetate utilizing SO^2-₄/Sm₂O₃ as catalyst Iso-amylacetate has been widely applied in chemical engineering, food and dope fields as a kind of important chemical engineering material and food additive. Concentrated H2SO4 is usually utilized as a catalyst for traditional production process of iso-amylacetate, which has some mortal bugs such as low selectivity, likely production carbonization and serious environmental pollution. In this present section, the nanosolid superacid SO^2-₄/Sm₂O₃ catalytic activity for the esteriflcation reaction of isoamyl alcohol and acetic acid was investigated in detail. A comparison of the nanosolid superacid with concentrated H2SO4 and conventionally synthesized non-nanometric superacid SO^2-₄/Sm₂O₃ indicated that the newly-synthesized product had a higher cataly更多还原