长链正构双烯与乙炔选择性加氢负载型纳米钯金属催化剂的研究

发布时间：2018-05-18 07:18

本文选题：钯金属催化剂 + 二氧化钛　；参考：《南京大学》2015年博士论文

【摘要】：双烯烃和炔烃选择性加氢是重要的石油化工和精细化工过程。本工作用微型催化反应评价和工业侧线反应评价结合X-射线粉末衍射(XRD)、比表面积和孔结构测试、CO吸附、热重-差热分析(TG-DTA)等多种物理化学手段研究了纳米Ti02为载体的负载型纳米钯金属催化剂长链正构双烯选择性加氢反应性能,系统和深入地探讨了纳米Pd/TiO2催化剂成型工艺、载体孔结构、催化剂几何形状、Pd金属在成型后的Ti02载体上的分布对催化剂长链正构双烯烃选择性加氢反应性能的影响,初步探讨了纳米碳管(CNTs)为载体的负载型纳米钯金属催化剂乙炔选择性加氢反应性能,为开发双烯烃和炔烃高选择性加氢实用新型纳米催化剂提供了重要参考信息。主要研究结果如下：1.发明了一种负载型纳米Pd/TiO2催化剂成型新方法。将Pd/TiO2粉末催化剂先经氢还原处理,再以A1203为粘结剂挤出成型,在高纯氮气保护下进行热处理。所制备的纳米Pd/TiO2成型催化剂具有优良机械强度和长链正构双烯选择性加氢反应性能。系统地研究了不同造孔剂对成型后纳米Ti02载体孔结构以及Pd/TiO2和催化剂长链正构双烯选择性加氢反应的影响,发现以硬脂酸铝为造孔剂的Pd/TiO2催化剂具有优良的长链正构双烯选择性加氢性能。2.发现成型的负载型纳米Pd/TiO2催化剂几何形状以及活性组份Pd金属在Ti02载体上分布方式对催化剂长链正构双烯选择性加氢反应性能有一定影响。三叶草形Pd/TiO2催化剂比圆柱形Pd/TiO2催化剂具有更优良的长链正构双烯选择性加氢反应性能。活性组份Pd金属在三叶草形TiO2载体上呈非均匀的壳型分布的催化剂比均匀分布的催化剂具有更高的长链正构双烯加氢选择性。3.研制了不含其它粘结剂的纯Ti02三叶草形载体,以其负载的Pd金属催化剂经工业侧线反应评价,结果表明其长链正构双烯选择性加氢反应性能优良、运行稳定。4.发现碳纳米管(CNTs)为载体的负载型钯金属催化剂活性金属Pd在管内外表面的分布状态以及载体管径大小对催化剂乙炔选择性加氢反应性能有很大影响。Pd金属分布在CNTs管外表面比分布在内表面具有更高的生成乙烯选择性,这是因为位于管外的Pd与CNTs载体发生电子相互作用导致Pd金属具有更高的电荷密度；Pd金属分布在CNTs管外表面的催化剂,管径减小乙炔转化率降低,这是由于管径较小的CNTs外表面电荷密度较大,与管外的Pd金属电子相互作用更强。
[Abstract]:Selective hydrogenation of diolefins and alkynes is an important petrochemical and fine chemical process. In this work, micro-catalytic reaction evaluation and industrial side-line reaction evaluation combined with X- ray powder diffraction (XRDX), specific surface area and pore structure were used to test CO adsorption. Various physical and chemical methods, such as thermogravimetric differential thermal analysis (TG-DTA), were used to study the selective hydrogenation of long chain n-diene over supported nano-palladium metal catalyst (Ti02). The forming process of nanocrystalline Pd/TiO2 catalyst was systematically and deeply discussed. The effect of pore structure and geometry of catalyst on the selective hydrogenation of long chain diolefin on Ti02 carrier was investigated. The selective hydrogenation of acetylene over supported nano-palladium metal catalyst supported on carbon nanotubes (CNTs) was preliminarily discussed, which provided important reference information for the development of high selectivity hydrogenation of diolefin and alkynes. The main results are as follows: 1. A new forming method of supported nano Pd/TiO2 catalyst was invented. Pd/TiO2 powder catalyst was treated by hydrogen reduction, then extruded with A1203 as binder, and then heat treated under the protection of high purity nitrogen. The nanocrystalline Pd/TiO2 catalyst has excellent mechanical strength and long chain diene selective hydrogenation performance. The effects of different pore-making agents on the pore structure of nano-scale Ti02 carrier and the selective hydrogenation of Pd/TiO2 and catalyst were studied. It was found that the Pd/TiO2 catalyst with aluminum stearate as pore-making agent had excellent selective hydrogenation performance of long chain n-diene. It was found that the geometry of the Pd/TiO2 catalyst and the distribution of PD metal on the Ti02 support had a certain effect on the selective hydrogenation of long chain n-diene. Clover Pd/TiO2 catalyst has better performance in selective hydrogenation of long chain normal diene than cylindrical Pd/TiO2 catalyst. The hydrogenation selectivity of the active component PD metal on the clover TiO2 support is higher than that of the homogeneous catalyst with a long chain diene hydrogenation. A pure Ti02 clover carrier without other binders was prepared. Its supported PD metal catalyst was evaluated by industrial side-line reaction. The results showed that the long chain n-diene selective hydrogenation reaction was excellent and the operation was stable .4. It is found that the distribution of active metal PD on the surface of the supported palladium metal catalyst and the diameter of the support tube have great influence on the catalytic performance of selective hydrogenation of acetylene. The outer surface of CNTs tube has higher ethylene selectivity than that of distributed inner surface. This is due to the electron interaction between PD and CNTs support outside the tube, which results in higher charge density of PD metal and lower acetylene conversion due to the distribution of PD metal on the outer surface of CNTs tube. This is due to the larger charge density on the outer surface of CNTs with smaller tube diameter and stronger interaction with PD metal electrons outside the tube.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：O643.36;TB383.1

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