Study On The Alcoholysis Of Furfural Residue To Methyl Levulinate

With the rapid growth of global energy demand and the emergence of worsening environmental problems,biomass energy has received more and more attention.Furfural residue is a kind of biomass waste which is produced by the hydrolysis of the pentose component of the biomass materials such as corn cob,corn stalk,rice husk,cottonseed husk and the agricultural and sideline products.It is an important biomass material for the conversion of levulinate esters.Methyl levulinate(ML),as a new chemical product,is widely used in energy,spice additive and other fields.The preparation of methyl levulinate from furfural residue has the advantages of low cost and environmental friendliness,and after pretreatment,the multistage utilization of furfural residue can be realized,the utilization efficiency can be improved,and high value-added chemicals can be obtained.The production process of methyl levulinate from furfural residue and aluminum sulfate as catalyst was studied.Firstly,the production of methyl levulinate using glucose as raw material was investigated,the effects of different technological conditions and water on the reaction were investigated,and the possible reaction pathways of converting glucose into methyl levulinate were proposed.Then the process of producing methyl levulinate from furfural residue was studied.Finally,furfural residue was pretreated by different pretreatment methods to investigate the effect of the pretreatment furfural residue on the yield of methyl levulinate.The main research content is as follows:1.In the experiment of preparing methyl levulinate by glucose,the influence of raw material concentration on the reaction was first investigated,and the concentration was screened out to be 20 g/L.Then,the catalytic performance of a series of metal sulfates in the catalytic preparation of methyl levulinate was investigated in methanol and methanol with low concentration of sulfuric acid,and the best catalytic performance of Al2(SO4)3 was screened out,and the optimal dosage of Al2(SO4)3 for 0.72 g glucose was 0.24 g.The effect of reaction time and reaction temperature on the reaction was investigated by single factor experiment.The optimal reaction condition was 4 h,170 ?,and the maximum yield was 61.60 mol%.Finally,the effect of water content on the total amount of levulinic acid(LA)and methyl levulinate was investigated.It is concluded that the water content of 50% can increase the total yield of both of them the most,and the total yield is up to 70.88 mol%,and the possible reaction pathways were proposed.At the end of the experiment,the recycling performance of Al2(SO4)3 was explored.After repeated use for 5 times,the yield of methyl levulinate was 57.20 mol%,still maintaining a good activity,indicating that Al2(SO4)3 is a recyclable catalyst.2.Firstly,the furfural residue was treated by drying and screening,and then the catalyst selection and single factor experiment were carried out for the preparation of methyl levulinate from furfural residue by alcoholysis.The optimal reaction conditions were: aluminum sulfate 0.5 g,reaction time 3 h,reaction temperature 180 ?,and the yield of methyl levulinate was 20.21 wt%.Then the effect of water content on the yield of methyl levulinate in the experiment was investigated.The results showed that the total yield of both levulinic acid and methyl levulinate increased the most with 50% water content,and the total yield was 23.33 wt%.Finally,the influence of temperature variation on the experiment was studied,and the response surface experiment was designed.It was concluded that the total yield of levulinic acid and methyl levulinate in the first stage was up to 25.64 wt% when the reaction temperature in the first stage was 198.05 ? and the reaction time was 1.50 h,while that in the second stage was 163.28 ? and the reaction time was 1.30 h.3.Firstly,basic hydrogen peroxide,sodium hydroxide and formic acid were used to pretreat furfural residue,and cellulose analyzer was used to determine the composition of furfural slag before and after pretreatment,and he chemical bond changes were analyzed by infrared spectroscopy.The results showed that the content of cellulose in furfural slag after pretreatment with formic acid increased obviously,and the content of hemicellulose and lignin were also decreased effectively.The cellulose content after formic acid pretreatment increased from 40.01% to 71.91%,the hemicellulose content decreased from 9.31% to 4.39%,and the lignin content decreased from 44.50% to 18.26%.The pretreatment furfural residue was used to prepare methyl levulinate.Based on the experimental results in the previous chapter,the method of response surface optimization was used to optimize the process of the two stages.The results showed that the total yield of levulinic acid and methyl levulinate reached 45.02 wt% when the reaction temperature of the first stage was 194.76 ? and the reaction time was 1.93 h,and that of the second stage was 166.43 ? and the reaction time was 1.06 h.Finally,the quality balance and the preliminary economic analysis are carried out,and the results show that the use of pretreatment can realize the graded utilization of furfural residue,which not only saves the cost and improves the economy of the process,but also makes the products more diversified and provides more possibilities for the comprehensive utilization of furfural residue.