| Nowadays, fossil energy depletion and climate deterioration are driving the development of alternative clean energy sources and climate deterioration are driving the development of alternative clean energy sources. Lignocellulose is the most abundant source of biomass originating from plant photosynthesis in nature, so biomass resources (especial in straw biomass) to high-value transformation has stuided the focus of people. Due to the particular of straw structure, straw depolymerization is to change or remove all kinds of structure and/or chemical barrier make effective components fully exposed in order to enhance conversion effect of straw. The study on different method depolymerization was used to deal with the corn stalk of corn stalk. It is further to catalytic hydrogenation sample of depolymerization into polyol so that to provide effective way for the further use of straw polymer structure, the results were given as follows:(1) Straw hydrolysis of ferulic acid content is up to 2.0483 mg/mL in hydrolytic liquid. Duo to ferulic acid was connected to lignin and hemicellulose by ester, the composition of lignin monomer was mainly G-lignin, followed by H-lignin and S-lignin. The results showed that the optimum conditions were:NaOH concentration 2%, temperature 80℃, time 4 h and 58.38 wt% of lignin while the cellulose content increased from 42.02 wt% to 60.15 wt%.(2) Corn stalk, as the research objective, was pretreated using alkali, acid, alkali-acid and acid-alkali. The surface structure exhibited rough and pore structure, characteristic absorption peaks of lignin and hemicellulose were reduced or even disappear in the infrared spectrum. The lignin contents were decreased from 28.04% to 11.54% and 12.14% after alkali-acid and acid-alkali pretreatment of corn stalk, while the cellulose contents were increased from 42.02% to 75.12% and 77.68%, respectively.(3) Ni-W/MCM-41 of different load were prepared by impregnation method, Ni17W3 alloy was evidenced in 5% Ni-15% W/MCM-41 by X-Ray diffraction spectra. The change of active Ni binding energy was discovered by X-Ray photoelectron spectra, the 3% Ni-15% W/MCM-41 catalyst caused an increase in binding energy shifting to 852.8 eV, comparing with the typical Ni0 binding energy of Ni2p3/2 at 852.2 eV. With increasing Ni loadings to 7% and 10%, the Ni2p3/2 signal shifted from 852.8 eV to 853.8 eV. The valence state of the metal W was changed that the lower value of W6+/W5+ was found in the 5% Ni-15% W/MCM-41. The W6+/w5+ increased and W0 intensity of binding energy decreased with the increase of Ni loading. The value of Ni/W comparison to XPS anlysis and theory value were found that the nickel was enriched on the surface of Ni-W/MCM-41 catalyst.(4) While using the catalyst of 5% Ni-15% W/MCM-41 on the catalytic hydrogenation of different pretreated straw, it found that the yield of polyol with alkali pretreatment was significantly higher than that with acid pretreatment. Moreover, the yield of polyol with acid pretreatment first and then alkali pretreatment was up to 61.4%(EG:61.13 wt.%, 1,2-PG:0.27wt.%).(5) The study of catalytic hydrogenation of pure cellulose, starch, C6 sugar (a-glucose and β-glucose), C5 sugar (xylose and Arabia sugar), it found that the yield of polybasic alcohol of catalytic hydrogenation of pure cellulose and soluble starch were 50.77% and 33.91%, respectively. Not just ethylene glycol and 1,2-propylene glycol, as compared with product distributions of C6 sugar, the glycerol was also obtained from C5 sugar catalytic hydrogenation, while reported an possible reaction mechanism of sugar to polyol. |
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