【作者】 陈金花；

【导师】 曹洁明；

【作者基本信息】 南京航空航天大学 ， 有机化学， 2010， 硕士

【摘要】 以多糖类有机化合物为模板调控无机晶体的生长是近年来一个新的研究方向。多糖是各种单糖的缩聚物,是地球上最丰富的可再生天然有机物之一。多糖的相对分子量比较大,大多带有负电荷,由于是一种多羟基的高分子物质,所以在分子间可以通过氢键形成超分子,作为模板来引导纳米粒子的生长。利用多糖类有机化合物的种类差异,可以制备出具有不同结构和独特性能的无机纳米材料。利用生物多糖制备纳米材料有很多优点,如多糖资源丰富,可再生,成本低廉;制备过程中的化学反应都在水体系中进行;多糖在合成纳米材料的过程不但充当模板剂,有些甚至还充当稳定剂、还原剂。这就避免了以往纳米材料制备过程中使用有机溶剂、有机表面活性剂、强还原剂等高毒害物质,满足绿色合成的要求。由于纳米材料具有高表面积,呈现了极好的催化性能。本论文将多糖类有机化合物引入金属氧化物与金属纳米材料的制备中,并研究其中几种金属纳米材料在有机合成反应中的催化性能,主要包含以下四个方面的研究内容:(1)用一种简单、绿色的方法通过以淀粉为模板合成具有高比表面积的NiO纳米颗粒。产物形貌新颖且具有良好的赝电容性质。同时,我们研究了煅烧温度和模板用量对产物结构参数的影响,并提出了NiO纳米颗粒的形成机理。同时探讨不同模板(葡聚糖)对多孔NiO的制备的适用性以及淀粉模板对于其它多孔金属氧化物制备(Co3O4)的适用性。(2)利用可溶性淀粉和乙酸盐作为前驱体,在氮气气氛下热处理淀粉与乙酸盐的混合物,通过一种简单的绿色合成方法制备了碳保护的纳米镍和碳保护的纳米钴两种复合材料,样品具有较高的比表面积,在空气中具有很好的稳定性和耐酸性。(3)利用葡聚糖为模板和还原剂制备了银/碳复合物。并以醛、炔、胺三组分的偶联反应(A3)为模型,对纳米银/碳复合物在有机反应中的催化性能进行了初步研究。以银/碳复合物为催化剂,以54 %收率成功制得了炔丙基胺衍生物。(4)水热法制备空心微球结构金属氧化物并研究其超电容性能。报道两种制备方法:一种是利用葡萄糖和金属盐前驱体混合一步水热、热处理最终得到金属氧化物空心球;另一种是首先水热制得胶体碳球,然后以胶体碳球为硬模板,制得金属氧化物空心球。制得的样品均具有较高的比表面积和较好的超电容性能。更多还原

【Abstract】 It is a new researching area of controlling the growth of inorganic crystals by using polysaccharide as template. Polysaccharide is the condensation polymer of saccharide, which is one of the richest renewable natural organic macromolecules on the earth. It usually has large molecular weight and has negative charges. Polyhydroxylated macromolecules present dynamic supramolecular associations facilitated by inter- and intra-molecular hydrogen bonding resulting in molecular level capsules, which can act as templates for nanoparticle growth. The structures and properties of inorganic crystals can be controlled by various kinds of polysaccharide templates with different conformation and molecular weight. It has many advantages. For example, polysaccharide is readily available, renewable and low cost. Besides, the chemical reaction for the nanomaterials using polysaccharide as the template can be carried out in aqueous system. In some reactions, polysaccharides not only can act as template agent, but also act as stabilizer and reducing agent. This method can efficiently avoid some toxic organic chemicals such as organic solvents, strong reducing agents, and fulfills the requirement of green chemistry. As compared to bulk materials, nanoscale materials catalysts exhibit perfect catalytic activities because of their large surface areas. In this paper, polysaccharide has been used as the template for the preparation of metal oxides and metals nanomaterials. And we also study the catalytic activities of resultant nanomaterials in reaction of three-component coupling of aldehyde, alkyne, and amine(A3).The main contents of this thesis are as follows:Firstly, we demonstrate an easy and environmentally friendly synthetic route to prepare NiO nanoparticles with large BET surface area by using starch as sacrificial template. The sample has favorable faradaic pseudocapacitive behavior and novel shape. The effects of the starch content and the calcination temperature on the structural parameters of the resultant NiO were studied. And the formation mechanism of the NiO nanoparticles was proposed. Furthermore, the method has also been demonstrated for the other polysaccharide and the other metal oxide (Co3O4). Secondly, carbon-protected metallic nanoparticles (nickel and cobalt) composites have been prepared by the pyrolysis of the mixture of soluble starch and acetate in N2 flow. The obtained samples possess mesoporous structures and high BET surface areas. And the obtained samples are highly stable in air and strong acid.Ag/C complex was prepared by using polysaccharide as template and reducing agent. With the three-components coupling reaction of amine, alkyne and aldehyde as prototype, the catalytic property of the nanoparticle was also studied. The propyl amine was achieved successfully with 54 % yield by using Ag/C as calatyst.Thirdly, we have prepared metal oxides hollow sphere via a hydrothermal approach. The electrochemical properties of the samples were studied. Two methods are reported. The first method: various metal salts were dissolved together with glucose in water, then metal oxides hollow spheres were prepared by heating treatment of the mixtures. The second method: 1) hydrothermal synthesis of colloidal carbon spheres, 2) the synthesis of metal oxides hollow sphere using the resulting colloidal carbon spheres as template. The resulting samples have large BET surface areas and have favorable faradaic pseudocapacitive behavior.更多还原