【作者】 闫智培；

【导师】 林鹿；

【作者基本信息】 华南理工大学 ， 制浆造纸工程， 2010， 硕士

【摘要】 随着化石能源的逐渐枯竭以及为达到减排温室气体保护环境的需要和实现人类可持续发展的目标,从可再生资源特别是木质生物质生产生物燃料和化学品成为许多国家的重要发展战略和科学研究的热点领域。木质生物质转化为生物燃料和化学品是是通过先将木质生物质分解产生葡萄糖等小分子化合物,再进一步转化为生物燃料和化学品。因此,探索如何高效得将葡萄糖转化为生物燃料和化学品,对增加木质生物质的利用途径和提高利用效率是非常有意义的。本文以葡萄糖为原料,利用固体酸催化其水解产生5-羟甲基糠醛,主要副产物为乙酰丙酸,这两种化合物都是活性很强的平台化合物,可转化为多种用途极广的化合物。然后研究了5-羟基糠醛氢解转化为适用于交通环节的生物燃料2,5-二甲基呋喃的工艺和转化路径。此外,本文还研究了乙酰丙酸还原转化为γ-戊内酯的工艺和反应路径。研究表明,磷酸锆固体酸能够在水/正丁醇两相体系中有效的催化葡萄糖转化为5-羟甲基糠醛,主要副产物为乙酰丙酸。最优的反应条件为:温度180 oC,反应时间1.5小时,磷酸锆与葡萄糖的质量比为1/2,有机溶剂为正丁醇,有机层与水层的体积比为1.6∶1。在该反应条件下,葡萄糖的转化率为96%,5-羟甲基糠醛的选择性可达44%;乙酰丙酸的摩尔得率为16%。我们还对使用前后的磷酸锆催化剂进行了对比,并认为其可以再利用。此外,我们提出了葡萄糖酸水解产生5-羟甲基糠醛的反应路径。5-羟甲基糠醛转化为2,5-二甲基呋喃的最适宜的反应条件为:反应温度220 oC、氢气分压2.0 MPa,Ru/C催化剂用量20%,反应时间1.0小时。在该条件下,5-羟甲基糠醛的转化率达到100%,2,5-二甲基呋喃的摩尔得率达到69.2%。我们利用XPS和XRD研究了使用前后Ru/C表面性质的区别,得出使用后的Ru/C催化剂仍具有一定的活性,可以再利用。最后,我们提出了5-羟甲基糠醛在液相中氢解转化为2,5-二甲基呋喃的反应路径。乙酰丙酸加氢制备γ–戊内酯的适宜的反应条件:温度130 oC,反应压力1.2 MPa,催化剂用量5.0%,溶剂无水甲醇,搅拌速度为1000 rpm。该条件下原料乙酰丙酸转化率达92%,产物γ-戊内酯选择性99%。我们还研究了催化剂重复利用时的催化效果。最后,提出了乙酰丙酸加氢制备γ–戊内酯的反应路径。更多还原

【Abstract】 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.更多还原