负载钯镍双金属在当归内酯加氢中的协同作用研究

发布时间：2018-04-19 00:29

本文选题：当归内酯 + 双金属催化剂　；参考：《华东师范大学》2017年硕士论文

【摘要】：在多相催化反应过程中使用负载型双金属催化剂通常可以获得高于单金属的原子经济性和高活性。在生物质转化中,α-当归内酯(α-AL)作为一种新的生物质平台化合物,可用于制备多种具有应用前景的化合物。本文围绕α-AL加氢制备伽马戊内酯(GVL)的高效催化剂开展研究,考察了 Pd-NiO(Ni)双金属催化剂的结构及组成等因素对加氢活性的影响,论文主要包括如下内容:1、制备了一系列不同Ni负载量(2-40wt.%)的NiO/SiO2材料、并负载微量Pd(0.2 wt.%),考察了 NiO负载量及Ni物种价态在αα-当归内酯釜式加氢反应中的构效关系。结果表明Pd-xNiO/SiO2系列催化剂可以在温和条件下(室温,0.3 MPa氢气)高活性高选择性催化α-AL加氢至GVL。在Ni负载量高于2%的Pd-xNi/SiO2催化剂中大量金属Ni的存在抑制了 Pd纳米粒子的加氢活性。Pd和NiO紧密结合形成的多相结构为加氢活性中心。2、合成了一系列不同粒径的NiO/SiO2载体,系统研究了不同Ni价态、粒径的载体材料负载Pd后得到的Pd-NiO(Ni)双金属催化剂在不同溶剂中对于α-AL在固定床装置加氢反应的活性。结果表明,Pd-NiO/SiO2系列催化剂在H20和四氢呋喃(THF)中都表现出高加氢活性和稳定性,并且表面的NiO表现出良好的抗积碳能力。通过在反应器中原位还原获得的Pd-Ni/SiO2在THF溶剂中随着反应的进行而逐渐失活,催化剂活性降低程度和Ni的粒径大小密切相关。相比较而言,双金属催化剂在水相体系中表现出良好的稳定性。H2O作为一种绿色溶剂比非质子溶剂THF在该反应中具有更好的应用前景。
[Abstract]:The atom economy and high activity of supported bimetallic catalyst are usually higher than that of single metal in heterogeneous catalytic reaction.伪 -Angelica lactone (伪 -ALL), as a new biomass platform compound, can be used to prepare many promising compounds in biomass conversion.In this paper, the efficient catalyst for the preparation of gamma-pentanolactone (GVLL) from 伪 -AL hydrogenation was studied. The effects of the structure and composition of Pd-NiO- Ni) bimetallic catalyst on the hydrogenation activity were investigated.The main contents of this paper are as follows: 1. A series of NiO/SiO2 materials with different Ni loading amounts (2-40wt.t) have been prepared, and a small amount of Pd(0.2 wt. has been loaded. The structure-activity relationships of the NiO loading amount and the valence state of Ni species in 伪 -Angelica lactone hydrogenation reaction have been investigated.The results show that Pd-xNiO/SiO2 series catalysts can catalyze the hydrogenation of 伪 -AL to GVL under mild conditions (0. 3 MPa hydrogen at room temperature) with high activity and high selectivity.The presence of a large amount of metal Ni in the Pd-xNi/SiO2 catalyst with Ni loading of more than 2% inhibited the hydrogenation activity of PD nanoparticles. The multiphase structure formed by the close combination of PD and NiO was formed as the hydrogenation active center. A series of NiO/SiO2 carriers with different particle sizes were synthesized.The activity of Pd-NiO- Ni) bimetallic catalysts with different Ni valence and particle size for 伪 -AL hydrogenation in fixed bed was studied in different solvents.The results showed that Pd-NiO / Sio _ 2 series catalysts exhibited high hydrogenation activity and stability in H20 and THF, and the surface NiO exhibited good resistance to carbon deposition.The Pd-Ni/SiO2 obtained by in situ reduction in the reactor was gradually deactivated in THF solvent, and the decrease of catalyst activity was closely related to the particle size of Ni.In comparison, the bimetallic catalyst exhibited good stability in aqueous system. H2O as a green solvent had a better application prospect than the non-proton solvent THF in the reaction.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O621.251

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