Study On Conversion Of Cellulose Into Levulinic Acid And γ-Valerolactone In γ-Valerolactone Solvent

In this study,cellulose was mainly converted into levulinic acid andγ-valerolactone with solid acid in γ-valerolactone.Firstly,the conditions of cellulose into levulinic acid and γ-valerolactone was optimized;and then using lignin as carrier to prepare solid catalyst for cellulose conversion;optimized the reaction conditions for levulinic acid and formic acid into γ-valerolactones;and finally,deduce the reaction path of the the whole reactions.It is found that γ-valerolactone does not change the crystal structure of microcrystalline cellulose.The experimental results showed that the effects of different reaction conditions of temperature,time,catalyst dosage is 185 o C,120 min,and 0.15 g respectively.Under the conditions,the concentration of levulinic acid is3.05 g/Land the yield was 46.85%,moreover,formic acid is 1.25 g/L and the yield was 48.45%.With lignin as carrier for catalyst preparation,the characterization of total acid is48.7 μmol/g,L acid more than B acid and average pore size is 4.13 nm,which belongs to the pore structure,the surface area of the catalyst was 21.16 m2/g,the trend of hydrolysis of cellulose to levulinic acid is similar to that of CMHT.Under the optimal conditions of CMHT,levulinic acid was 35.64% using lignin as catalyst.The optimization of reaction conditions of levulinic acid and formic acid intoγ-valerolactones reaction are 160 o C,0.2 g catalyst,3 m L triethylamine and 180 min.Under this condition,the highest conversion rate can reach 87.26%,theγ-valerolactones rate can reach 80.75%,but the catalyst recycling was unsatisfactory,the product yields were greatly reduced.In the whole process of the products were determined by HPLC and NMR,and the reaction path was analysed.Firstly,cellulose hydrolyzed into glucose,and the glucose into 5-hydroxymethyl furfural,levulinic acid and formic acid.Formic acid decomposes to produce hydrogen and carbon dioxide,levulinic acid is attacked by hydrogen atom to form 4-hydroxypentanoic acid and further it is turned intoγ-valerolactone.