Catalytic Hydrolysis Of Cellulose Into High-valued Chemicals

With the drain of fossil fuel, searching for renewable alternative energy resources has become an urgent task for human-beings. Lignocellulose, consisting of agricultureal waste, trees and grasses, is the most abundant renewable resource, which is the most promising alternatives to fossil based industry.The main component of biomass is cellulose-a polymer comprising glucose units linked by beta -1,4-glycosidic bond, with each chain interconnected by hydrogen bonds, which makes cellulose a tough compound to break down. In this paper we studied the hydrolysis of cellulose based on he reaction medium and catalytic separation.Transformation of cellulose into 5-hydroxymethylfurfural was studyed in ionic liquid 1-ethyl-3-methylimidazolium chloride([EMIM]Cl), 1-butyl-3-methylimidazolium chloride([BMIM]Cl) and 1-allyl-3-methylimidazolium chloride([AMIM]Cl). The influence of different acidic catalysts, chromium chloride, the amount of cellulose concentration and the moisture to the yield of HMF were also investigated. With the hydrochloric acid as catalyst, the yield of HMF is about 50%. The acidic ionic liquid ([BMIM]HSO₄) and([BMIM] H₂PO₄)was employed both as solvent and catalyst for hydrolysis of cellulose. Furthermore, we studied the kinetic model of hydrolysis of cellulose and established the simple kinetic model. The study shows that the overall reaction consists of a first order reaction and two consecutive zero-order reaction.A great deal of effort has been put to the degradation of cellulose by enzyme and mineral acid. But catalyst and product separation seems difficult and energy-consuming. To overcome the problem, we designed and synthesized the magnetic sulfuric solid acid catalyst for the first time. The catalyst showed high performance for the hydrolysis of different carbohydrates including cellobiose, starch, cellulose and even corn cobs, producing glucose yield of up to 96 percent from cellobiose, and 50 percent glucose yield was obtained from amorphous cellulose. Corn cob was selected as lignocellulose for hydrolysis, which gave the total reducing sugar (TRS) yield of 45%. By using this new catalyst, we saved an energy-consuming process to separate the solid acid and concentrate the glucose. Importantly, the catalyst could be recycled without obvious deactivation.