【作者】 丁艳；

【导师】 喻宁亚； 银董红；

【作者基本信息】 湖南师范大学 ， 有机化学， 2010， 硕士

【摘要】 负载型纳米金催化剂是一类新型的工业和环保催化材料,其在CO低温氧化,醇、醛的选择氧化,烯烃环氧化,碳氢化合物的催化燃烧,卤代有机化合物的氧化分解及氮氧化物的去除等许多领域表现出了广泛的应用前景。本论文采用多种不同的方法制备了双硫-离子液体功能化的有机-无机杂化介孔材料及含氨基的聚离子液体,以其为载体制备了一系列纳米金催化剂,并考察了所得催化剂在烯烃环氧化中的催化性能,具体内容如下：(1)先合成含二硫醚-离子液体单元的有机硅氧烷,在不同表面活性剂作用下,以其为有机硅前驱体与正硅酸乙酯或九水硅酸钠共水解-缩聚,一步合成了三种具有不同织构性质的桥键嵌入型有机-无机杂化介孔材料。利用材料孔道表面硅羟基为还原剂及二硫醚对金纳米粒子的稳定作用成功制备了相应的负载型纳米金催化剂。在一系列烯烃的环氧化反应中,三种催化剂表现出了不同的催化性能。整体而言,具有一维孔道的复合纳米金催化剂较有着三维交叉孔道的催化剂有更好的催化性能；而其中,具有较大孔径的催化剂又有更好的催化性能。值得指出的是,三种复合纳米金催化剂都有着相当好的重复使用性能,所有催化剂在使用10次后,催化活性基本不变。(2)将上述含二硫醚-离子液体单元的有机硅氧烷后嫁接到纯硅SBA-15材料孔道表面,利用材料孔道表面硅羟基为还原剂及二硫醚对金纳米粒子的稳定作用制备了负载型纳米金催化剂,并采用N：吸附-脱附、TEM、EDX-mapping、29Si MAS-NMR、FT-IR及UV-Vis等手段对其进行了表征。将该催化剂应用于α-蒎烯环氧化反应,考察了反应时间、温度、氧化剂用量、催化剂用量等反应条件对α-蒎烯环氧化规律的影响。在优化条件下,α-蒎烯转化率和环氧化物选择性分别可达81.8%和94.9%,且催化剂在使用6次后,催化活性基本不变。(3)合成了氨基功能化乙烯基咪唑离子液体(AIL),利用氨基固定金纳米粒子以及双键的聚合作用,获得了聚离子液体固载金纳米粒子的催化齐(GNPs-P-AIL)。采用红外光谱、紫外-可见光谱和透射电子显微镜等方法对GNPs-P-AIL进行了表征。结果表明,AIL在固定金纳米粒子并聚合后仍然保持着离子液体的基本结构,金纳米粒子分布均匀,粒径为6-8 nm。GNPs-P-AIL催化剂对苯乙烯环氧化具有较好的催化活性,以双氧水为氧化剂,在60℃下反应6h时,苯乙烯的转化率和环氧苯乙烷的选择性分别可达81.5%和88.3%。更多还原

【Abstract】 Supported gold nanoparticles (GNPs) are a new kind of catalytic materials, which have been demonstrated to be very promising catalysts in many important industrial processes and environmental protection fields, such as low-temperature CO oxidation, selective oxidation of alcohols or aldehydes, epoxidation of olefins, catalytic combustion of hydrocarbons, oxidative decomposition of halogenated organic compounds, removal of NOx, etc. In this dissertation, a series of periodic mesoporous organosilica (PMO) materials incorporating disulfide-ionic liquid moieties and a NH2-containing ionic liquid polymer were prepared and used as support for fabricating supported GNP catalysts. Catalytic performance of the resultant catalysts was investigated in epoxidation of olefins. The main contents discussed were as follows:(1) An organic bridged silsesquioxane precursor containing disulfide-ionic liquid moieties was synthesized and co-condensed with tetraethoxysilane or sodium silicate in the presence of different templates, leading to three PMO materials with various pore architectures. GNPs, derived from in-situ reduction of aqueous chloroaurate ions by the silanols located on the pore surface of the PMO materials, were captured by sulfide groups, giving rise to relative GNP/PMO composite catalysts. In a series of epoxidation reactions of various olefins, the three GNP/PMO composite catalysts showed different catalytic performance. In general, the catalysts with 1-D pore architecture revealed better catalytic performance than the catalysts with 3-D pore architecture, meanwhile, the larger pore size in the catalysts with 1-D pore architecture, the better catalytic performance. It should be noted that the three GNP/PMO composite catalysts possess rather excellent reusability; they could be reused for 10 times without significant loss of catalytic activity.(2) The above-stated organic bridged silsesquioxane precursor was grafted onto siliceous SBA-15 via a post-synthesis procedure. The resultant PMO material was employed for fabricating GNP/PMO composite catalyst via a process involving in-situ reduction of aqueous chloroaurate ions by the silanols located on the pore surface and successive capture of the formed GNPs by sulfide groups. The obtained GNP/PMO composite catalyst was well characterized by means of N2 adsorption-desorption, TEM, EDX-mapping,29Si MAS-NMR, FT-IR and UV-Vis. Using epoxidation of a-pinene as test reaction, the effects of reaction time, reaction temperature, oxidant amount and catalyst amount on catalytic performance of the GNP/PMO composite catalyst were investigated systemically. Under optimum conditions, the conversion of a-pinene and the selectivity toα-pinene epoxide were as high as 81.8% and 94.9%, respectively; moreover, the catalyst could be reused for 6 times without significant loss of catalytic activity.(3) An amino-functionalized ionic liquid of N-(3-aminopropyl), N(3)-(vinyl)-imidazolium bromide (AIL) was synthesized and used to stabilize gold nanoparticles (GNPs). Further polymerization of the resultant GNP-containing AIL led to a composite catalyst with GNPs being supported by ionic copolymer (GNPs-P-AIL). The obtained composite catalyst was characterized by means of FT-IR, UV-Vis, and TEM. It was found that GNPs-P-AIL remained the structure of ionic liquid moieties in the parent AIL after GNPs loading and successive polymerization processes and that GNPs in the composite catalyst dispersed uniformly with the particle size of 6-8 nm. GNPs-P-AIL showed good catalytic performance in the epoxidation of styrene using H2O2 as the oxidant. The conversion of styrene and the selectivity for styrene oxide were as high as 81.5% and 88.3%, respectively, when the reaction was performed at 60℃for 6 h.更多还原