Hydrothermal Transformation Of Plant Biomass To Produce High Value-added Chemicals

5-HMF is an important intermediate product which is widely used in medicine,food and chemical industry.Many traditional preparations of 5-HMF are based on sugar substances from food crops.Soughting new raw materials for the preparation of 5-HMF is effective to reduce the non-edible consumption of food crops.Biomass energy is a promising new energy source.In this study,bagasse was used as raw material to explore the conversion of biomass to produce high value-added chemicals such as 5-HMF.This research mainly explores the influence of pretreatment method,the processing time,the type of catalyst,catalyst concentration,duplex system,dual phase ratio,reaction pressure,reaction pH,reaction temperature,reaction time and material ratio to the production of 5-HMF and the generating mechanism of 5-HMF from the bagasse.It was found that treating bagasse with alkali could effectively increase the yield of5-HMF.In this study,the catalytic effects of aluminum chloride,chromium phosphate and chromium chloride were compared.It was found that chromium chloride was the best catalyst,and the higher the catalyst concentration,the higher the yield of 5-HMF.The effects of water/ethanol,water/2-butanol and pure water on the yield of 5-HMF were compared in this study.It was found that the yield of 5-HMF was the highest when water/ethanol was used as the reaction system.It was found that the yield of 5-HMF increased when increase the filling rate of the reactor.The yield of 5-HMF showed a trend of decline after rising first with reaction temperature rising.The best yield of 5-HMF come out when the reaction temperature reaches 290℃,after that,the yield decreasing gradually.In this study,the pH was adjusted by sulfuric acid,and it was found that the yield of 5-HMF continued to increase with the decrease of pH.This indicates that acidic conditions are favorable for the formation of 5-HMF.The yield of 5-HMF decreased with the increase of reaction time after 5 min.It seems that the lower the material ratio,the higher yield of 5-HMF and the better the hydrothermal degradation of bagasse will be.The orthogonal experiment and response surface were used in the research progress.The results showed that alkali treatment could effectively remove the lignin in bagasse.The two-phase system could effectively prevent the degradation of 5-HMF.This study used the bagasse which treated 15 min by alkali as raw material,10 mg/m L chromium chloride as catalyst,according to the filling rate was 40%（V%）,material ratio was 5%（wt%）filling the reaction kettle.The yield of 5-HMF can steady at 8.14%in the two-phase system whose pH=1,V_water:V_ethanol=1:6.6,reacted 5 min at 290℃.Cellulose and hemicellulose are the main reactants in the reaction process of forming 5-HMF.They hydrolyzed into monosaccharides step bu step.Glucose in the monosaccharides was isomerized into fructose,which further removed water molecules to form enol intermediate.The enol intermediate can form 5-HMF by removing another two water molecules.Compared with other preparation methods,this method is simpler and more efficient,it not only reduce the disturb of the lignin but also preserve the 5-HMF effectively.When 5-HMF is generated,there are also some other important chemicals generated,such as 5-methylfurfural,phenol,4-methoxyphenol,2-methoxyphenol and 2,6-dimethoxyphenol.