The Designing And Performance Research For A Separable System Of Solid Acid Catalysis

Acid-catalyzed reaction is one of the important components in catalytic field where liquid acids such as H2SO4, HCl, HF are used as catalysts, and the environmental pollution and energy consumption arising therefrom had heavy impacts on the development of modern society. As the concept of "green-tech" were gradually accepted, solid acid catalysts developed recently had received considerable attentions with their excellent catalytic characteristics and environmental friendly behaviour. Moreover, solid acids have so many advantages such as strong acid strength, high catalytic efficiency, pollution-free, easy separation, no equipment corrosion, reusability and recycling, that they have become an increasing concern of the majority of scientists and have broad application prospects. In this study, we majored on the properties of heteropoly acid catalysts and sulfonic acid-induced carbon-based solid acid catalysts and their applications in acid catalytic system, modified both kinds of catalysts according to their advantages and disadvantages, and designed to build efficient and separable solid acid systems to be applied in hydrolysis and esterification reaction.The first part of this article was a literature review, we described the classification and application of solid acid catalysts, highlighted the preparation methods and application research in organic reactions of both heteropoly acid catalysts and carbon-based sulfonic solid acids. At last, the work assumptions were expressed in this article.The second part concluded the experiment section and the section of experiment results and discussions, solid acid catalysts prepared in this work were applied to the reactions of hydrolysis and esterification, and their structure and acid catalytic performance were also be characterized and discussed in this part.1. An efficient homogeneous catalytic system catalyzed by phosphorus tungsten acid with low-energy consumption was build. In the condition of microwave-assisted heating system, we tested its catalytic performance on the hydrolysis of cellulose:the effects of reaction factors such as, the amounts of catalyst, reactant ratio, the temperature and reaction time, on the hydrolysis of cellulose were studied systematically to optimize the reaction conditions. Under the optimized experimental conditions, the yield of glucose got from cellulose hydrolysis catalyzed by HPW was around 75%. After the reaction, phosphotungstic acid could be separated from reaction system by ether extraction method which resolved the issue of recycling of phosphotungstic acid. The results of experiments tested for the reusability of catalyst proved that the activity of phosphotungstic acid remain unchanged in reusing processes. That corresponded the basic requirements of green chemistry.2. A heteropoly acids catalyst modified with laurylamine was synthesized and its catalytic performance on hydrolysis reaction was studied:the effects of the amounts of catalysts, reaction time, and temperature on the hydrolysis reaction were discussed to get the optimizing reaction condition of the process. The experiment results showed that the catalyst has higher catalytic activity, could be easily seperated and recycled for many times by comparing with other heterogeneous acid catalyst.3. A fiberous carbonaceous solid acid promoted by TiO2 was synthesized and its catalytic performance on both reactions of esterification and hydrolysis were studied: the experimental results show that the yield of ethyl acetate catalyzed by the catalyst could be 81% for esterification of acetic acid and ethanol under optimal experimental conditions. After the reactions, the catalyst presented the cotton shape and could be seperated from the reaction system. Taking advantage of the structural features of the catalyst, it can be used in fixed-bed reaction which also provides a new way for broadening the application scope of solid acid.