Catalytic Conversion Of Levulinic Acid And Research Of Friedel-crafts Acylation Over Solid Acid Catalyst

With the depletion of fossil resources,it has became the important subject faced by the current international to develop renewable sources of raw materials and efficient catalytic system for chemical raw materials and intermediates of green manufacturing.In recent years,levulinic acid is a widely concerned platform chemical,which can be continuously obtained from cellulose,hemicellulose and other renewable biomass.Cellulose and hemicellulosis are the richest and cheapest biomass resources on the earth,and the catalytic synthesis process of levulinic acid has been relatively mature.Therefore,it has great application prospect to explore the catalytic synthesis of the downstream fine chemicals by using the widely available and inexpensive levulinic acid as the starting material.In addition,with the development of green chemistry,the use of solid acid catalyst in the Friedel-Crafts reaction can avoid the drawbacks of using traditional catalysts.Based on this background,the catalytic synthesis of ethyl levulinate,?-valerolactone was as a research focus in this paper,the green catalytic system about the catalytic conversion of levulinic acid into high value-added fine chemicals has been developed and studied.It also tries to extend the catalyst to similar research field.The main contents of this paper are as follows:1.In the study of catalytic synthesis of ethyl levulinate,the silicotungstic acid modified solid acid catalyst was successfully designed with the commercially silica gel as the catalyst carrier.The research results showed that 20 wt.%STA/SGS catalyst had fine catalytic performance.The yield of ethyl levulinate was as high as 97.0%at the optimum reaction condition?catalyst/levulinic acid weight ratio 1:5,levulinic acid/ethanol molar ratio 1:8,reaction temperature 84?and reaction time 4 h?.2.In the study of continuous catalytic synthesis of ethyl levulinate,the cerium salt of phosphotungstic acid catalyst based on commercially silicone carrier was successfully designed.It was found that 30%CeTPA/SGP catalyst at the optimum conditions?reaction temperature 160?,levulinic acid/alcohol mole ratio of 1:10?showed high catalytic activity with about 98.5%levulinic acid conversion rate and 99.5%selectivity of ethyl levulinate for 50 h.The catalyst showed good stability.3.In the study of catalytic synthesis of?-valerolactone,Cu-Zn/ZrO₂-Al₂O₃ cheap metal catalyst was successfully designed.The research results showed that the conversion rate of ethyl levulinate was 96.0%and the selectivity of?-valerolactone was 94.0%in the optimal process.The experiment results of stability showed that the catalytic performance of the catalyst had not changed significantly in 30 h.4.In the study of Friedel-Crafts acylation reaction over heteropoly acid catalyst,ZIF-8 matrix of silicotungstic acid catalyst was successfully designed.The catalyst has a good catalytic activity in the reaction of anisole.It can be obtained the best results that the conversion of anisole 99.2%and selectively toward p-benzoylanisole 93.5%over 20 wt.%STA/ZIF-8 catalyst.In addition,the experimental results of different acylation reagents and reaction substrate can prove that the catalyst has good catalytic universality.