Study On The Conversion Of Glucose To 2,5 Dimethylfuran And γ Valerolactone

Mounting global environmental and energy problems have stimulated increased efforts towards synthesizing biofuels and high-value chemicals from renewable biomass resources, especially woody biomass.Woody biomass usually have to be changed to micromolecule (such as glucose) before they are converted to biofuels and high-value chemicals. Therefore, the study on how glucose can converted to biofuels and high-value chemicals in high yield is significatively.The dehydration of glucose to 5-hydroxymethylfurfural and levulinic acid; the hydrogenolysis of 5-hydroxymethylfurfural to produce 2,5-dimethylfuran; the hydrogenation of levulinic acid to produceγ-valerolactone were studied in this paper.Studies show that the dehydration of glucose reaches the maximum selectivity of nearly 44% 5-hydroxymethylfurfural with a glucose conversion of about 96% for 1.5 h reaction time at 180°C, with a ZrP to glucose ratio of 1:2 in the n-butanol/water system (Vorg./Vaq. = 1.6). The stability of catalysts ZrP was investigated by comparing surface structure variations of fresh and used catalysts. In addition, a mechanism for the conversion of glucose to 2,5-dimethylfuran and levulinic acid was proposed.To produce 2,5-dimethylfuran, the optimal reaction conditions for 5-hydroxyme thylfurfural hydrogenolysis were as follows: temperature of 220°C, hydrogen partial pressure of 2.0 MPa, 20% Ru/C catalyst dosage, and 1.0 h reaction time. Under these conditions, the conversion of 5-hydroxymethylfurfural was nearly 100%; the yield of 2,5-dimethylfuran was 69.2%. The surface structure variations of the fresh and used catalysts were characterized by XRD and XPS. In addition, a mechanism for the conversion of 5-hydroxymethylfurfural to 2,5-dimethylfuran was proposed.The optimum preparation conditions ofγ-valerolactone by hydrogenation of levulinic acid catalyzed by Ru/C were as follows: temperature at 130°C, hydrogen pressure at 1.2 MPa, dosage of catalyst at 5.0%, the solvent being methanol, the agitation speed was 1000 rpm and a reaction time of 160 min. The conversion rate of levulinic acid toγ-valerolactone was found to be 92%, and the selectivity ofγ-valerolactone was 99%. We also studied the conversion efficiency catalyzed by reused Ru/C. Furthermore, the reaction pathway for the hydrogenation of levulinic acid was proposed.