Preparation Of5-hydroxymethylfurfural From Wasted Cotton Stalk With Hydrothermal Method

Abstract:5-hydroxymethylfurfural (5-HMF) is an important furyl compound which can be produced from the degradation of biomass. It can be to the preparation of a variety of furan derivatives with oxidation, hydrogenation and condensation reactions on active groups hydroxy and aldehyde.5-HMF is considered to be a key intermediate between biomass chemical and petrochemical industrial organic chemistrynd expected to become the new platform compound. Therefore,5-HMF has been extensively researched.The process for preparation of5-hydroxymethylfurfural from wasted cotton stalk with hydrothermal method were studied. To determine the optimum process conditions, the influences of various factors such as reaction time, reaction temperature, the catalyst types and dosage on the degradation of cellulose and5-HMF synthesis were analyzed. The kinetics of preparation of5-hydroxymethylfurfural from wasted cotton stalk with hydrothermal method with or without SO42-/ZrO2catalyst were studied and the performance of the catalyst in the reaction process was determined.The results of the study on operating conditions show as follows: cellulose degradation rate increased by93.07%and the yield of5-HMF increased by6.25times with the temperature riseing from200℃to230℃; with reaction time increasing from15min to120min, cellulose degradation rate increased by26.60%and the yield of5-HMF increased firstly and then decreased. The yield of5-HMF was reached maximum after90min reaction and the value was25.3%. The catalysts selected have a promoting effect on the degradation of cellulose and the preparation of5-HMF. The catalyst SO42-/ZrO2-ZnO (n (Zr):n (Zn)=7:3) had best effect on cellulose degradation and the rate of cellulose degradation could up to97.52%. The comprehensive effect of SO42-/ZrO2catalyst on cellulose degradation and the preparation of5-HMF was best and the rate of cellulose degradation would reach to94.43%and the yield of5-HMF to25.3%. The optimal operating conditions obtained were as follows:reaction temperature230℃, reaction time90min, the dosage of SO42-/ZrO2catalyst was20%.The results of kinetics study showed that catalyst SO42-/ZrO2had a positive catalytic effect both on the degradation of cellulose and the preparation of5-HMF. With the addition of catalyst SO42-/ZrO2, the selectivity of5-HMF can be maximum increased by1.57times. The activation energy of cellulose degradation reaction decreased from106kJ·mol-1to96.7kJ·mol-1and the activation energy of the preparation of5-HMF decreased from119.4kJ·mol-1to84.2kJ·mol-1.