纳米空心二氧化硅的合成及在蛋壳形催化剂制备的应用.doc

清 华 大 学 毕业设计说明书(论文) 作 者: 吴文宏 学 号： 0858290105 学院(系): 专 业: 化学工程与工艺 题 目: 纳米空心二氧化硅的合成及在蛋壳形 催化剂制备的应用 指导者： 评阅者： 2012年06月 毕业设计说明书（论文）中文摘要 摘要 本文以正硅酸乙酯（TEOS）为硅源，氨水溶液为催化剂，聚乙烯吡咯烷酮（PVP）功能化的聚苯乙烯为，在乙醇介质中利用一步法制得纳米空心二氧化硅，并用TEM，XRD，BET，TG，FTIR 等表征手段对SiO2粉体进行分析。 首先,以苯乙烯（St）为单体，过硫酸铵为引发剂，聚乙烯吡咯烷酮为分散剂，水为分散介质，单分散聚合法制备功能化的聚苯乙烯，可得到平均粒径为90nm的聚苯乙烯微球。以这种微球为，在乙醇/氨水介质中，正硅酸乙酯发生水解和缩合，在聚苯乙烯微球包覆形成SiO2，同时PS核被溶解，得到纳米空心二氧化硅微球。研究氨水用量，TEOS用量及反应时间等因素对二氧化硅微球形貌和产率的影响。 以空心纳米二氧化硅为Li3PO4催化剂载体，催化环氧丙烷的异构化，以硅胶作为载体的Li3PO4催化剂的催化效果进行比较。结果表明，使用空心球形二氧化硅代替硅胶作为催化剂载体可提高环氧丙烷转化率和烯丙醇的选择性，降低反应温度和副产物选择性。 关键词 ：中空纳米二氧化硅 模板法 环氧丙烷 烯丙醇 毕业设计说明书（论文）外文摘要 Title Systhesis of Nano hollow silica and the application in the preparation of the eggshell-shaped catalyst Abstract This article prepares hollow SiO2 nanoparticles with the template one step method, using tetraethyl orthosilicate (TEOS) as the silica source, ammonia water as the catalyst, polyvinylpyrrolidone (PVP) functionalized polystyrene as the templates .The basic performaces of SiO2 powder has been characterized by means of TEM,XRD,BET and FTIR . First, using styrene as the monomer, ammonium persulfate as the initiator, polyvinylpyrrolidone( PVP) as the stabilizer, prepares PVP functionalized polystyrene microspheres(PVP/PS),which average size is 90nm. In ethanol/ammonia water medium , hydrolyzation and condensation of TEOS were completed, SiO2 shells were built around the PVP/PS templates , meanwhile PS nuclears were dissolved ,obtained hollow silica microspheres .The main factor influencing for the morphology and productivity of SiO2 as the amount of ammonia water, TEOS and reaction time etc were investigated. Using Nano hollow silica as Li3PO4 catalyst carrier, Li3PO4/SiO2 as the catalyst in the isomerization of propylene oxide, analyzes catalytic effects and compares with catalyst which using silica gel as the carrier. The results show that usi