不同形貌非晶态Ni-P催化剂的合成及金属与酶结合动力学拆分的研究

【作者】 杨勇；

【导师】 李辉；

【作者基本信息】 上海师范大学 ， 工业催化， 2010， 硕士

【摘要】 纳米技术与催化相结合,制备具有独特催化活性和选择性的高效催化剂,已成为催化科学工作者研究的主要方向。本论文主要将纳米技术与催化相结合,制备了一系列具有特殊形貌结构纳米催化剂,并考察了其不同形貌结构与催化活性和化学选择性之间的相互关系。最后,将纳米催化剂与酶相结合,动态动力学拆分手性化合物制备单一对映体结构的手性化合物。全文围绕以上两方面主要开展了以下几方面的工作:1)采用硬模板技术与化学镀相结合制备了具有二维六方结构的Ni-P非晶态合金。以刚性SBA-15为模板,孔道中的Pd纳米粒子为晶种引发镀液氧化还原反应,使镀液中沉积出来的Ni-P合金沿着SBA-15的孔道逐渐生长。将其孔道完全填满之后,用氢氧化钠溶液除去二氧化硅,得到了反相复制SBA-15孔道结构的Ni-P非晶态合金。通过XRD、TEM、BET、XPS等测试手段,对催化剂的形貌结构和表面电子性质进行了详细的表征。证明新鲜制备的材料为Ni-P非晶态合金,其较好地反相复制了SBA-15的孔道结构,具有较好的有序性结构。将制备的具有二维六方结构Ni-P非晶态合金应用于液相麦芽糖加氢反应中,展现出较高的催化性能。其有序孔道结构的存在有利于反应底物的传输,并增大了催化剂与反应底物的接触几率。2)采用纳米级的二氧化硅小球模板与化学镀技术相结合制备了具有空心结构的Ni-P非晶态合金催化剂。以尺寸较均一的二氧化硅纳米小球为模板,成功制备了尺寸同样较均一、具有中空形貌结构的Ni-P非晶态合金纳米球。同样,通过XRD、TEM、BET、SEM等测试手段,对催化剂的形貌结构和表面性质进行了详细的表征。证明了Ni-P非晶态合金纳米球具有明显的空腔结构,其壳层中存在蠕虫状的纳米级孔道结构,方便了空腔内外物质的传递。同样,具有空腔结构的Ni-P非晶态合金纳米球在液相麦芽糖加氢反应中展现出了比实心Ni-P非晶态合金纳米颗粒较高的催化活性。3)将Pd金属催化剂与生物酶相结合,动态动力学拆分了外消旋的苯乙醇。经典生物酶动力学拆分手性化合物的最大限制是其理论最大转化率为50%,而动态动力学拆分则能突破最大转化率50%的限制,其理论最大转化率能达到100%。本论文主要考察了以纳米金属Pd做为外消旋催化剂与生物酶结合拆分苯乙醇的一锅化反应体系,并优化了一锅化反应体系的反应条件。经过优化之后的反应体系能将82%的苯乙醇拆分出来。同时,经过对一系列苯乙醇同系物的拆分研究表明,此一锅化反应体系对醇的拆分具有一定的普适性。更多还原

【Abstract】 By nano-technology combined with catalysis, the preparation of efficient catalysts with a unique catalytic activity and selectivity become the main direction of research among catalytic scientists. This paper mainly focuses on preparation of a series of special morphologies of nano-catalyst, and studied the relationship between their morphology, catalytic activity and the chemical selectivity. Finally, the dynamic split of chiral compounds chiral compounds with the structure of a single enantiomer by combination of nano-catalysts and enzyme. Around these two main aspects, this paper is developed in the following areas:1)Two-dimensional hexagonal-arranged amorphous Ni-P alloy catalyst was prepared by combining hard template technology and electroless plating. SBA-15 as a rigid template and Pd nano-particles as seeds leading decomposition make Ni-P alloy gradually grow along the pore of SBA-15, and eventually completely fill the pore. After the removal of silicon with NaOH solution, amorphous Ni-P alloy catalyst with pore structure has been copied reversely. By XRD, TEM, BET, XPS and other testing methods, the morphology of the catalyst and surface electronic properties were examined in detail. The fleshly prepared amorphous Ni-P alloy catalyst, which has a better copy of the pore structure of SBA-15, has a better ordered structure. The catalyst performance was tested in maltose hydrogenation reaction, which show a high catalytic actitvity. The existence of ordered pore structure is conducive to the transmission and increasing contact area of the catalyst and the substrate2)The nano-scale silica ball was used as a template to prepare amorphous Ni-P alloy catalyst with a hollow structure by electroless plating technique. By using more uniform size of silica nano-ball as a template, hollow Ni-P alloy catalyst was successfully prepared with a more uniform structure of hollow morphology. Similarly, by XRD, TEM, BET, XPS and other testing methods, the morphology of the catalyst and surface electronic properties were examined in detail. It is proved that Ni-P alloy catalyst has obvious cavity structure, and its shell exists the worm-shaped nano-scale pore structure, and facilitates the exchange of materials within and outside the cavity. Similarly, of amorphous Ni-P alloy catalyst with a cavity structure showed higher catalytic activity than the solid nano-Ni-P alloy catalyst in maltose hydrogenation reactions.3)Combination of The Pd metal catalysts and enzyme is used into dynamic kinetic resolution of racemic benzene ethanol., the maximum limit in classical kinetic resolution of chiral compounds is the maximum theoretical conversion rate of 50%, while the dynamic kinetic resolution is to break its maximum conversion rate of 50% limit, the theoretical conversion rate can reach 100%. This thesis examines nano-metallic Pd catalyst and the enzyme as a combination of racemic phenylethanol split-pot reaction system. And the optimized one-pot reaction system and reaction conditions. After optimization of the reaction system, 82% of benzene in ethanol can be split out. At the same time, through a series of phenethyl alcohol homologue the split reaction, this one-pot reaction system is proved certainly universal.更多还原