Study On The Continuous Hydrolysis Of Biomass And Its Derivatization Reaction

With the increased depletion of fossil resources and serious environmental problems, people are looking for alternative renewable resources to solve energy,safety and environmental issues.Therefore, the development and utilization of renewable clean resources to replace the dwindling fossil resources has become an important direction of future energy research.Biomass, as a renewable organic carbon resource, is considered to be an ideal alternative to fossil fuels for the production of liquid fuels, fuel additives and chemicals, etc,. Cellulose, polymerization through glycosidic bond of hexoses in biomass, have been widely concerned. Due to its high degree of polymerization,difficult to dissociate and other problems, the utilization and industrial application of cellulose is difficult. Especially in the process of continuous hydrolysis of cellulose,the intermittent sampling is still used, which is not conducive to the true reflection of cellulose hydrolysis. 5- hydroxymethyl furfural, as an important platform molecular compound,itself and its downstream products have many application. It is of great significance to develop a new method to realize the industrial application of 5-HMF.At present, there are still some problems such as low yield, high reaction condition and high temperature and high pressure equipment in the study on the conversion of cellulose and sugar to 5-HMF.y-valerolactone and pentanediol, as important chemical raw materials, have many important applications.The study on the methods of their biological synthesis is very important to solve the problem of the source of the raw materials. At present, the catalytic hydrogenation technology has been widely used in the conversion of biomass materials, but there are still some problems, such as the catalyst deactivation, harsh reaction conditions, etc.In view of the above problems, we focus on the efficient conversion of cellulose to the downstream products. In order to study the reaction process, we divided the study into three parts. Including the development of continuous hydrolysis reactor online tracking system and the detection of cellulose to glucose reaction process, the application of Lewis acid catalysts to the conversion of carbohydrates to furfural under mild conditions, the effects of catalysts on the yield and product distribution were investigated in water and ethanol using cheap copper based catalysts.Initially, the composition and utilization technology of biomass are introduced firstly, and the hydrolysis of cellulose and its kinetic model are briefly reviewed. We reviewed the preparation methods and their downstream applications. In this chapter,the importance and function of 5-hydroxymethyl furfural were expounded. The following research ideas and directions are put forward. At the same time, the preparation and transformation of levulinic acid were reviewed.Then, the origin, technical difficulties and design mechanism of the continuous hydrolysis reactor are described. The design of continuous hydrolysis reactor to solve the problems of sampling and testing in the continuous hydrolysis of cellulose. We also study the design of the auxiliary continuous hydrolysis device through the preliminary experiment.We also introduce the conversion of cellulose carbohydrate to 5- hydroxymethyl furfural catalyzed by Lewis acid. Through the screening and study of homogeneous and heterogeneous Lewis acid catalysts, the high efficiency conversion of glucose to 5- hydroxymethyl furfural was achieved. It provides a new reaction system for the production of 5- hydroxymethyl furfural ?Finally, the conversion of levulinic acid (LA) into GVL by using the supported copper based catalyst and the conversion of GVL to pentanediol (PDO) were introduced. We used two copper based catalysts to achieve high yields of GVL in solvent ethanol and water, respectively. A good yield of GVL was obtained by hydrolysis and hydrogenation of sugars. In addition, the highly selective conversion of GVL to PDO was carried out using supported copper catalyst in ethanol.In this paper, cellulose carbohydrates were selected as the research object, and different methods and catalytic methods were used to realize the selective conversion of each step. The design principle of continuous hydrolysis reactor and the mechanism of structure-activity relationship of catalysts and reaction were expounded to provide theoretical support and experimental basis for the development of downstream products from cellulose by one-pot multistep.