有机-无机杂化固体酸催化纤维素定向转化为烷基葡萄糖苷的研究

As the most promising renewable feedstocks in place of fossil fuels, cellulose has received intense attention from governments and researchers over the world. There is an enormous amount of cellulose resources spread all over China, yet it is utilized inefficiency. Thus, developing new environmental friendly technologies for directing transformation of cellulose into value-added chemicals is an important method for the sustainable utilization of this resource. This project here is planned to use a series of orgnic-inorganic hybrid solid acids (HSA) as the catalysts, which are special ionic liquids loading a sulfonic acid group by covalent C-S bond, in the alcoholysis of cellulose to alkylglycosides (AGs) orientedly. Through investigating deeply the specific linkage between HSA and the glycoside bonds of cellulose in the reaction system, the factors which affect this interaction will be definited. Further more, the mechanism of stablization of the glycosyloxonium intermediate by the polyoxometal anion of HSA will be studied, followed by optimizing reaction conditions to inhibit the formation of 5-HMF and its derivatives. The mechanism of cellulose alcoholysis is researched by combination of control experiments and reaction kinetics studies. On the other hand, the methods of catalyst HSA's quick separation and recycle from reaction products, as well as the inactivation process of HSA should be studied. Finally, we will apply these results to synthesize AGs from alcohylysis of cellulose in some other short chain alcohols under the optimized reaction conditions.

纤维素资源是替代化石能源最有潜力的可再生非粮资源，近年来受到世界各国的重视。我国的纤维素资源数量庞大但利用效率低，研究环境友好的技术实现纤维素定向转化为重要的化学品是纤维素资源可持续性发展的必由之路。本项目拟使用共价负载磺酸基的离子液体型有机-无机杂化固体酸(HSA)催化纤维素醇解定向合成烷基葡萄糖苷。深入研究反应体系中HSA对纤维素糖苷键的特异性结合行为，明确影响其定向结合作用的因素，并研究HSA的多金属氧酸阴离子对糖基氧正离子中间体的稳定化作用机制，以此为指导来优化反应条件，进而抑制5-HMF的生成。采用控制实验关联反应动力学研究，来阐明纤维素醇解反应的机理。与此同时，研究催化剂HSA的失活规律以及其与反应产物的快速分离和循环利用方法。在最优反应条件下，将HSA应用于其它低碳链醇中的纤维素醇解反应，合成一系列烷基葡萄糖苷产品。

纤维素资源是替代化石能源最有潜力的可再生非粮资源，近年来受到世界各国的重视。我国的纤维素资源数量庞大但利用效率低，研究环境友好的技术实现纤维素定向转化为重要的化学品是纤维素资源可持续性发展的必由之路。本项目创制了新型共价负载磺酸基离子液体型有机-无机杂化固体酸(HSA)的催化剂，用于催化纤维素醇解定向合成烷基葡萄糖苷。深入研究了反应体系中HSA对纤维素糖苷键的特异性结合行为，明确了影响其定向结合作用的因素，并研究HSA 的多金属氧酸阴离子对糖基氧正离子中间体的稳定化作用机制，以此为指导，进一步优化了反应条件，进而抑制5-HMF 的生成。采用控制实验关联反应动力学研究，来阐明纤维素醇解反应的机理。与此同时，研究了催化剂HSA的失活规律以及其在反应后混合溶液中的快速分离和循环利用方法。在最优反应条件下，将HSA 应用于其它低碳链醇中的纤维素醇解反应中，合成了一系列烷基葡萄糖苷产品。