膨润土负载型催化剂的制备及催化有机反应研究

【作者】 王敏；

【导师】 赵斌； 张恒；

【作者基本信息】 曲阜师范大学 ， 有机化学， 2010， 硕士

【摘要】 膨润土负载型催化剂是一类优良的环境友好型催化剂,在目前催化研究领域中占有重要的位置。它具有制备工艺简单、催化选择性好、催化活性高、无污染、易与反应体系分离以及可循环使用等优点。本论文首先论述了膨润土负载型催化剂开发的意义及催化剂的研究进展,针对催化剂的制备和应用中存在的问题,较为系统地研究了催化剂的制备条件,进而研究了催化剂在合成缩酮、酯化、烷基化等有机反应中的应用,为实现该类催化剂的工业化应用打下了坚实的基础。本论文主要包括以下两个方面：1.催化剂的制备和表征首先对原料膨润土进行提纯和酸化处理,较系统地考察了酸化处理条件对膨润土结构及性能的影响,然后选择出最佳酸化程度的活性膨润土作为载体,负载钛锆复合氧化物和氯化锌制备固体酸催化剂。利用X射线衍射、红外光谱、比表面积、程序升温脱附等测试技术对催化剂的结构、比表面、酸中心等进行了表征。实验结果表明：适度的酸化处理并不会破坏膨润土的层状结构,同时还可以使膨润土表面积增大、酸中心增加、酸量增多,有利于活性组分的负载。活性膨润土负载钛锆复合氧化物和氯化锌之后,通过程序升温脱附测定可以发现负载膨润土的酸性位和酸量都有增加。然后对催化剂负载量和焙烧温度进行了研究,发现负载量的多少和焙烧温度对催化剂结构的形成和稳定存在显著的影响。膨润土负载钛锆复合氧化物的钛锆比为1：1,焙烧温度在500℃时催化剂比表面积最大、催化活性最高；膨润土负载氯化锌催化剂在负载量为2.0mmol／g、焙烧温度在350℃时具有最大的比表面积,氯化锌和膨润土之间可以形成稳定晶相。2.催化剂催化有机反应研究利用缩酮反应和烷基化反应分别作为对膨润土负载钛锆复合氧化物催化剂与膨润土负载氯化锌催化剂的活性评价体系,研究不同制备条件对催化剂活性的影响以及催化剂的稳定性能,并系统地探讨了合成目标产物的工艺条件。实验结果表明：膨润土复合氧化物在催化缩酮的反应中表现出良好的催化活性,在钛锆摩尔比为1：1、焙烧温度为500℃时重复使用五次仍具有很高的活性；膨润土负载氯化锌催化剂在催化烷基化反应中表现出良好的催化活性,负载量为2.0mmol／g、焙烧温度在350℃时,催化剂活性最高并且可以多次重复使用,相对酸化膨润土而言两类催化剂的催化性能和稳定性都有不同程度的提高。另外,对膨润土负载钛锆复合氧化物在酯化反应中的催化性能以及膨润土负载氯化锌在脱氨环化反应中的催化性能进行了探索性研究,成功地催化合成了乙酸正丁酯、碳酸丙烯酯等化合物。实验结果表明膨润土负载催化剂具有很高的催化选择性和催化活性。更多还原

【Abstract】 Bentonite catalyst is a kind of excellent environment-friendly catalyst, which occupies an important position in the field of catalysis research. It has many advantages such as simple preparation process, high catalytical selectivity, high catalytical activity, non-polluting, easy to be separated from reaction system and being recycled. At the beginning of the thesis, it reviewed the development, application and the progress in the researching of bentonite catalysts. The present study mainly focuses on the preparation conditions and charaterisation of new bentonite catalysts and their application in the synthesis of ketal, esterification, alkylation, etc. The research results will be helpful to achieve the industrial application of such a kind of catalyst.The thesis is mainly divided into two parts:1. Preparation and characterization of catalystsUsing bentonite as the starting materials, purification and acidification of bentonite were carried out and acidic treatment conditions were explored and optimized firstly. Then the loading of metal titanium, zirconium mixed oxides and zinc chloride was studied using acidified bentonite with the best level of activity as the support. The structure, specific surface area and acid center of catalysts were characterized by X-ray power diffraction, infrared spectroscopy, N2 sorption analysis applying BET method and temperature programmed desorption technology. Based on these measurements, the results show that appropriate acidification treatment of bentonite not only does not destroy the lameller structure of bentonite, but also increase the specific surface area, the acid centers and the amount of acid, which can benefit the loading of active components on the bentonite support. It can also be found that the amount of acid centers and acid strength were increased after the load of titanium-zirconium composite oxides and zinc chloride in the temperature programmed desorption experiments. Then the effects of the amount of active components loaded and the calcinations temperature on the catalysts were studied. it is suggested that the effects of the amount of active components loaded and the calcinations temperature on the catalyst preparation, structure and stability are significant, and catalysts have higher special surface area and better catalytical activity when they are prepared by loading of titanium-zirconium composite oxides with Ti/Zr mole ratio 1:1, calcinations temperature 500℃. The catalysts loaded 2.0mmol/g of ZnCl2, and calcinated in the temperature of 500℃have largest surface area, and a stable crystal phase can be formed between zinc chloride and bentonite.2. Study of catalytical organic reactions using the bentonite catalystThecatalytical activity and stability of the newly prepared bentonite catalysts, prepared in different conditions, were studied by using ketal reaction and alkylation reaction as evaluation system, and the catalyst preparation conditions were optimized. The results have showed that the catalytic activity of bentonite supported titanium-zirconium composite oxides catalysts act excellent activity in the reaction of ketal. The catalysts prepared under the condition of Ti/Zr mole ratio 1:1, calcinations temperature at 500℃are good catalysts for catalyzing ketal reaction reaction, which still has very high activity after reused five times. Bentonite supported ZnCl2 catalyst by loading 2.0mmol/g of ZnCl2, calcinated at 350℃acts as an excellent active catalyst in the alkylation reaction. It has the best activity and can be used repeatedly. In addition, the catalytic activity of bentonite supported titanium-zirconium composite oxides catalysts in esterification reaction, bentonite supported ZnCl2 catalysts in deamination cyclization reaction was studied. Butyl acetate and propylene carbnate were prepared successfully. The results show that bentonite catalyst has good catalytic selectivity and catalyst activity.更多还原