Preparation Of 5-hydroxymethylfurfural From Rice Hull Cellouse Catalyzed By Tin Chloride Under Microwave Irradiation

Biomass energy is a renewable and clean energy source.The use of biomass energy can effectively alleviate the energy crisis and reduce the environmental impact of biomass waste.Rice husk is one of the agricultural wastes and can be used as a raw material for renewable energy.This agricultural by-product can be converted into a platform compound,5-hydroxymethylfurfural(5-HMF).However,the content of lignin and ash in rice husk is high,which inhibits the degradation of cellulose in rice hull to prepare 5-HMF.Therefore,pretreatment of rice husk can not only remove most lignin,but also reduce the crystallinity of cellulose.The porosity of the material is increased,so that the rice husk is degraded to obtain 5-HMF,and the rice hull must be saccharified as much as possible.This thesis has conducted a series of studies on how to use the rice husk preparation platform compound 5-HMF.In this thesis,the pretreatment method of rice husk,the effect of sodium hydroxide mass fraction on solid residual amount,cellulose content and lignin content were investigated.The conventional direct heating pretreatment method was used to treat rice husk with 3% NaOH solution.Preferably,the lignin content in the rice husk obtained by the pretreatment is 5.6%,and the solid residual amount,the cellulose content and the hemicellulose content are 1.79 g,50% and 8.3%,respectively.Then the pretreated pretreated rice husks were used for microwave degradation reaction.The product was analyzed by HPLC,and the yield of the obtained product was significantly increased.In the optimum reaction conditions,the microwave power was 420 W and the microwave irradiation time was 6 min.The dosage of tin chloride is 1.95 g,the mass fraction is 2.0% hydrochloric acid added 1.69 g,the rice husk cellulose is added 1.2g(cellulose content 0.6g),and the DMSO dosage is 10% of the reaction liquid volume,which is the optimal reaction condition.The yield of the obtained product was 26.5%.Finally,the lignin and ash in the rice husk were extracted,and the effects of the components in the rice husk on the process of cellulose degradation of 5-HMF were investigated.The experimental results showed that the amount of lignin added,the amount of ash added,and the pretreatment method were investigated.The effect of cellulose degradation reactions.From the experimental results,the yield of 5-HMF continued to decrease with the increase of lignin and ash added.When the content of lignin and ash exceeded 5%,the yield of 5-HMF decreased the most.In the shell method,after the rice husk pretreated with conventional NaOH,the yield of 5-HMF produced by cellulose degradation in rice hulls was the highest.