| 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. |
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