Studies On Supported Reagents Catalysts Of Using Montmorillonite As Support

This thesis aims to study the changes of the structure of montmorillonite after the treatment by acid and according to it ,select the best support to load ZnC12 to achieve the catalyst which have the best catalytic activity .At the beginning of thesis ,it related the importance of developing a type of solid acid catalysts and summarized the progress in the researching of environment friendly catalyst. Subsequently the preparation of ZnC12 loaded to catalyst and the relationship between structure and catalytic activity were intensively investigated .It抯 indicated that this catalyst have some high activity in F-C .So we can expect that heterogeneous in the reaction ,cleaning of production and lessening of pollution can be realized by using this catalyst .At last ,the application of this catalyst in alkylation was also studied .This thesis consists of three parts: The first part stated the preparation of supported reagent catalysts using montmorillonite as support, catalysts were prepared by envaporating to dryness a suspension of clay in methoanolic ZnC12 solution, major contents of preparation is that conditions been selected or be confirmed. Firstly, purification and acidification on montmorillonite have been taken up, acidic treatment condition have been explored .The results have showed the structure of montmorillonite have been destroyed severely.It also suggested that the catalytic activity have been obtained only by sufficiently acid treat. After acidic treatment for 4 h ,the layer structure of montmorillonite have been destroyed completely, and with it as support, the best catalytic activity was achieved. Secondly,the loading of ZnC12 was studied, which suggested that enough amounts of acid centers can抰 be formed if the loading is too low, neither is activity. The higher ZnC12 loading, the higher activity. But the overloading of ZnCl2 would make pores blocked and specific surface areas decrease, which made dispersity of ZnC12 loading on support decrease, and then led to lower catalytic activity. Therefore, the appropriate loading is a important factor for the catalytic activity. Finally activation of catalysts have been studied, and it was suggested that there was a best calcinations temperature. Because the temperature is too lower to grow acidic center, this will influence the catalytic activity . However, if temperature is I Abstract much too high, the acidic centers were lose, catalytic activity become lower. The conclusion was obtained by single factor condition. Subsequently, the condition of the preparation of the catalysts were optimized. At last, its stability and rebirth property were studied. The second part stated the relations of structure and property. The catalytic structural characterization was recorded using the XRD and TG-DTA, and surface acidity was measured using Harnmett indicators. It was suggested that the increase in activity is the result of a synergistic effect between the ZnCI2 and the support, leading to increasing in both the acidity and the acidic strength. It turned out that the catalyst is stable at lower temperature by studying the heat-stability, while some active centers lose during 450-550扖 which was recorded by TG-DTA. Therefore, in liquid reaction the catalyst has good property, and it was suggested that lowing of the activity is due to the amass charcoal. The third part relates the application of the catalysts in benzoyla...