微波辅助晶化法制备MWW结构分子筛的研究

发布时间：2018-01-31 03:34

本文关键词： MCM-22 分子筛微波合成　出处：《华东师范大学》2010年硕士论文　论文类型：学位论文

【摘要】： MCM-22分子筛是MWW拓扑结构的代表,其传统合成方法主要采用水热合成法,合成的时间至少需要4-5天。因此,降低能耗、缩短加热时间的新型合成方法的研究成为了当今研究的热点。近年来,微波技术被美国化学会列为绿色化学的重要成员而倍受瞩目,微波辅助法合成分子筛具有反应速度快,反应条件温和,能耗低,分子筛粒径分布窄,纯度高,形貌均一等优势,而被广泛应用于多种结构分子筛的合成(如MEL,MFI等)。迄今为止,MWW型分子筛尚无成功合成的报道,将微波辅助加热法应用于MWW拓扑结构分子筛的合成是本论文的核心研究方向。论文主要包括以下四部分内容：应用微波辅助法成功合成MCM-22分子筛,经过29小时微波晶化得到与传统水热法合成5天相同100%晶化的样品,有效地缩短了合成时间。通过XRD,SEM,FT-IR,ICP等技术进行表征,微波辅助合成样品具有高纯度,均一形貌,A1原子有效进入骨架等特征。并将微波与传统水热的合成样品通过晶化曲线,SEM图,FT-IR等进行对比,研究微波合成的机理及其优势。分别考察了微波合成方法、模板剂用量、晶化温度和硅铝比对合成的影响。结果发现,模板剂的用量是成功合成MCM-22分子筛的关键,采用多步微波法可以较单步法进一步缩短合成时间。其它因素与传统合成法规律基本相同。利用微波内加热原理,在合成体系中加入少量高介电常数溶剂作为添加剂(如甲醇,乙二醇,丙三醇),研究添加剂对合成分子筛的影响。实验结果发现,少量小分子甲醇作为添加剂可以进一步加快微波合成速度,得到高结晶度的纯相MCM-22分子筛。应用微波辅助合成B-MCM-22分子筛,并对其他杂原子MWW型分子筛如Ti-MWW等进行初步的研究。
[Abstract]:MCM-22 molecular sieve is the representative of MWW topology, its traditional synthesis method is mainly hydrothermal synthesis, the time of synthesis takes at least 4-5 days. Therefore, the energy consumption is reduced. In recent years, microwave technology has been listed as an important member of green chemistry by the American Chemical Society. Microwave-assisted synthesis of molecular sieve has the advantages of rapid reaction, mild reaction conditions, low energy consumption, narrow particle size distribution, high purity and uniform morphology. However, it has been widely used in the synthesis of various molecular sieves (such as MELL-MFI, etc.). So far, there is no report on the successful synthesis of MWW molecular sieves. The application of microwave assisted heating to the synthesis of MWW molecular sieve is the core of this thesis. MCM-22 molecular sieve was successfully synthesized by microwave-assisted method. After 29 hours of microwave crystallization, the same 100% crystallization samples were obtained from conventional hydrothermal synthesis for 5 days. The synthesized samples were characterized by XRDX SEMT-IR ICP and microwave assisted synthesis with high purity and uniform morphology. The Al atoms enter the skeleton effectively and the microwave is compared with the traditional hydrothermal synthesis sample by crystallization curve SEM and FT-IR to study the mechanism and advantages of microwave synthesis. The effects of microwave synthesis, the amount of template, crystallization temperature and Si / Al ratio on the synthesis of MCM-22 molecular sieve were investigated. The results showed that the amount of template was the key to the successful synthesis of MCM-22 molecular sieve. The multi-step microwave method can further shorten the synthesis time compared with the single-step method, and the other factors are basically the same as the traditional synthesis method. The influence of additives on the synthesis of molecular sieve was studied by using microwave internal heating principle and adding a small amount of solvent with high dielectric constant as additives (such as methanol, ethylene glycol, glycerol) in the synthesis system. A small amount of methanol as additive can further accelerate the microwave synthesis rate and obtain pure phase MCM-22 molecular sieve with high crystallinity. B-MCM-22 molecular sieve was synthesized by microwave assisted synthesis, and other heteroatomic MWW molecular sieves such as Ti-MWW were studied.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TQ424.25

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