Study On Preparation Of Levulinic Acid By Bagasse Acid Hydrolysis

Levulinic acid(LA)is an important biomass-based chemical.The preparation of LA from bagasse is of great practical significance for the comprehensive and efficient use of biomass.Biomass material bagasse is mainly composed of cellulose,hemicellulose and lignin.After high temperature dilute acid treatment,cellulose is mainly degraded into glucose,and the main hydrolysate of hemicellulose is xylose.In order to better study the LA process of bagasse hydrolysis,this experiment selects glucose and bagasse as raw materials,and the composition of the hydrolysate was analyzed;the effects of reaction temperature,dilute sulfuric acid concentration,reaction time and liquid-to-liquid ratio on the yield of LA by bagasse hydrolysis were studied;the obtained hydrolyzate is initially separated and purified.The main test contents and conclusions are as follows:1.The reaction of high temperature hydrolysis of monosaccharide glucose and xylose corresponding to cellulose and hemicellulose was studied.It was found that levulinic acid was mainly derived from glucose,and only a small amount was derived from xylose,which is lignocellulose.The cellulose may be a good starting material for levulinic acid,while the hemicellulose hydrolysis yields only a small amount of levulinic acid.The main components of glucose hydrolysis are analyzed,including residual glucose concentration,including residual glucose concentration,including residual glucose concentration,levulinic acid concentration,5-hydroxymethylfurfural(5-HMF).The LA was obtained at temperature(210.0 ?),sulfuric acid concentration(3.0%),reaction time(30.0 min),LA concentration is 13.37 mg/mL.2.Taking bagasse as the research object,the single factor experiment shows the temperature(210.0?),sulfuric acid concentration(3.0%),liquid to material ratio(15:1)and reaction time(30.0 min),the yield of levulinic acid obtained was 15.37%.3.The optimized process conditions for the hydrolysis of bagasse to levulinic acid were obtained by response surface specification analysis.The liquid-to-material ration?the acid hydrolysis temperature?the acid hydrolysis time and the sulfuric acid mass fraction was 16.57 mL/g,215.77?,34.31 min,3.84%respectively.The LA yield was 16.604%.According to the optimization results of the above factors,the actual conditions for the operation were selected to carry out the verification test.The liquid-to-material ratio?the hydrolysis temperature the reaction time was 16.0 mL/g,216.0?,34.0 min,and the sulfuric acid mass fraction was 3.8%.In the parallel verification test,the yield of LA was 16.25%.4.Ion exchange method was used to separate and purify levulinic acid from bagasse hydrolysate,and D301 resin with higher adsorption capacity was selected as the packing of ion exchange column.The experiment was carried out to study the bagasse hydrolyzate on the ion exchange column packed with D301 resin.The breakthrough curve and elution curve were determined to be 0.84 BV/h,the outflow volume was 56.4 mL,the bagasse hydrolysate was applied to the column,the ion exchange column had an aspect ratio of 10,and the elution flow rate was 0.84 BV/h.1 mol/L formic acid is eluted as an eluent.The eluate was collected,subjected to vacuum distillation,and a fraction of 130-140 ?was collected,and finally,the total yield of LA was 67.1%,and the purity was 78.0%.