| With the rapid development of economic society,people's demand for coal,oil and other fossil resources is increasing.But their presence reserves is limited,regeneration time is long(basic as non-renewable)and the use of them bring a lot of problems like serious environmental pollution.Therefore,there is an urgent need to develop a new kind of renewable and sustainable resource to instead the fossil fuels.Lignocellulose,as a kind of natural polymer materials,has a lot of advantages like large production,renewable and carbon neutral,that makes it the best choice to replace those fossil resources.Ionic liquid,which is a new green solvent,enable lignocelluloses to convert efficiently.This article explored the change of structure and composition of the lignocellulose in the reaction system of oxidant with ionic liquid,and further improved the efficiency of enzyme hydrolysis and produced high valueadded chemicals,such as 5 – HMF.Finally,the performance of this reaction system to overcome the resistance structure of lignocellulose was evaluated.In this paper,the oxygen-ionic liquid reaction system was firstly explored to judge its effect on the robust structure of lignocellulose.Four kinds of reaction systems were designed,they were oxygen-ionic liquids,oxygen-sodium hydroxide,oxygen-ionic liquids-sodium hydroxide,oxygen-sodium hydroxide-hydrogen peroxide-ionic liquids respectively.Through a series of analyses,which included the analysis of the three major components in the solid residue before and after the reaction,the crystallinity of cellulose,infrared analysis,the average molecular weight of lignin and the performance analysis of subsequent enzyme hydrolysis,as well as the corresponding components analysis in the liquid part,the best reaction system was detected,that was oxygen-sodium hydroxide-ionic liquid system,and the synergistic effect of oxygen/ionic liquid was furtherly proved.According to the oxidative degradation of lignin and high affinity of ionic liquid,this reaction system can improve the performance of mass transfer,realize the selective degradation removal of lignin,and further overcome the reluctant structure of lignocelluloses effectively.The detection results of the liquid solution got from the above five kinds of reaction systems using high performance liquid chromatography(HPLC)and ion chromatography showed that the content of glucose acid,HMF,organic acid and glucose in the liquid were too low,therefore,in order to realize the aim of converting lignocellulose components directly and more effectively,the system of pyridine sulphur trioxide-ionic liquid was designed.Firstly,under this reaction system,the microcrystalline cellulose was dealt with,and then the glucose.By analyzing the transformation rule of products,the cellulose reaction characteristics of dissolution,hydrolysis,dehydration conversion were discussed,this system can realize a high yield of glucose acid which was close to 50% yield,and the yield of HMF can achieve 20%,and other organic acids were got too,for instance,formic acid,levulinic acid.Ionic liquid can effectively destroy the crystalline region of cellulose,break down its dense structure,and improve the reaction accessibility of the reactive group.Sulphur trioxide pyridine with ionic liquid can achieve the selective oxidation of glucose,provided a new kind method to prepare glucose acid.Oxidant coordinated ionic liquid handling lignocellulose can realize high efficient and reasonable conversion of biofuels and chemicals,consequently,enrich the biomass refining technology system. |
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