Hydrolysis Of Furfural Residues Study To Levulinic Acid

In recent years,catalytic convertion of levulinic acid using lignocellulosic biomass as raw material has achieved much attention.In this paper,the catalytic hydrolysis of furfural residue under high-temperature condition was studied,aimed at increasing the yield of levulinic acid and realizing the efficient utilization of biomass resource.Lignocellulosic biomass consists of cellulose,hemicellulose and lignin.Levulinic acid could be made by cellulose hydrolysis.The lignin content could be reduced and the crystal structure of cellulose could be destroyed by pretreatment.In this work,the residue was pretreated by ionic liquid?[BMIM][CI]?which showed positive effect on dissolving cellulose and decreased the crystallinity of cellulose from 28.49%to 3.32%.Consequently,further hydrolysis was promoted.The results show that the optimal levulinic acid yield?62.46%?was achieved under the condition of sulfuric acid concentration of 2%,the FeCl₃·6H₂O amount of 3%and the temperature of 200?.In order to increase the yield and selectivity of levulinic acid.The effects of reaction temperature,acid concentration and liquid-solid ratio were investigated.The results showed that levulinic acid yield reached 35.48%under the conditions of liquid-solid ratio of 6:1,temperature of 200? and acid concentration of 3%.Four kinds of Lewis acids were added to increase reaction rate,and it was found that the trend for their catalytic effects was FeCl₃·6H₂O>LiCl·H₂O>AlCl3·6H₂O>ZnCl2 and levulinic acid yield reached the maximum?53.88%?when the amount of FeCl₃·6H20 was 3%.NaCl was added to enhance the solubility of cellulose and inhibit the production of lactic acid in side reaction,and the levulinic acid yield reached the maximum?69.18%?when the amount of NaCl was 7%.To deeply understand the process of cellulose hydrolysis,the hydrolysis process of furfural residue under the condition of solid-liquid ratio of 1:8 and the FeCl₃ concentration of 5%was investigated.The effect of different reaction temperatures?180?,190O,200? and 210??on glucose concentration and levulinic acid yield were studied,and it was found that the levulinic acid yield reached the maximum?44.28%?under the conditions of the temperature of 200 ?,the FeCl₃ concentration of 5%and the time of 40 min.The kinetic parameters were determined and analyzed based on the results of levulinic acid yield.The activation energies of furfural residue hydrolysis and glucose degradation for levulinic acid were 102 kJ/mol and 110 kJ/mol,respectively.