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Effect of polyvinylpyrrolidone on the catalytic properties of Pd/γ-Fe 2 O 3 in phenylacetylene hydrogenation
Reaction Kinetics, Mechanisms and Catalysis ( IF 1.7 ) Pub Date : 2020-09-01 , DOI: 10.1007/s11144-020-01857-x
Alima K. Zharmagambetova , Eldar T. Talgatov , Assemgul S. Auyezkhanova , Nurmukhamet Z. Tumabayev , Farida U. Bukharbayeva

Maghemite nanoparticles modified with polyvinylpyrrolidone were synthesized using the chemical co-precipitation method. Palladium ions have then been immobilized on the PVP/γ-Fe2O3 magnetic support. The Pd-PVP/γ-Fe2O3 catalyst obtained was characterized using X-ray diffraction, thermogravimetry coupled with differential scanning calorimetry and quadrupole mass spectrometry, scanning electron microscopy combined with energy dispersive X-ray analysis, transmission electron microscopy, nitrogen adsorption–desorption and vibrating sample magnetometry. Morphology, microstructure, particle sizes and textural properties of the Pd-PVP/γ-Fe2O3 were compared with those of the unmodified Pd/γ-Fe2O3 catalyst, synthesized using the same method. The polymer has affected the size of γ-Fe2O3 nanoparticles and their agglomeration, forming compact microstructure with decreased mesopores (4.5 nm). Palladium nanoparticles with size of 3–5 nm were found both on the surface of the PVP/γ-Fe2O3 particles (6–10 nm) and inside the pores formed by them. The Pd-PVP/γ-Fe2O3 has demonstrated improved catalytic properties in phenylacetylene hydrogenation under mild conditions of 40 °C and 0.1 MPa, compared to Pd/γ-Fe2O3 and similar catalysts prepared using polyethylene glycol and pectin. The hydrogenation rate of C–C triple bond on Pd-PVP/γ-Fe2O3 achieved 2.8 × 10–6 mol s−1 and selectivity to styrene was 92%. The catalyst showed weak ferromagnetic and soft magnetic properties (MS = 51 emu g−1, Mr = 5.4 emu g−1, and HC = 71 Oe) and, therefore, can be easily recovered with an external magnet and reused for at least 11 runs without significant degradation in the catalytic activity.



中文翻译:

聚乙烯吡咯烷酮对Pd /γ-Fe2 O 3在苯乙炔加氢中催化性能的影响

采用化学共沉淀法合成了聚乙烯吡咯烷酮改性的磁赤铁矿纳米粒子。钯离子已被再固定在PVP /γ-的Fe 2 ö 3磁性支撑。将Pd-PVP /γ-的Fe 2 ö 3使用X射线衍射所得的催化剂的特征在于,热重加上差示扫描量热法和四极杆质谱,扫描电子显微镜能量分散型X射线分析,透射电子显微镜,氮吸附组合-解吸和振动样品的磁力。形态,微结构,颗粒大小和Pd的PVP /的纹理特性γ-的Fe 2 ö 3用那些未改性的Pd /γ-的Fe相比2 ö 3催化剂,使用相同的方法合成。聚合物已经影响γ-Fe的大小2个ö 3纳米颗粒和它们的附聚,形成具有降低的介孔(4.5纳米)紧凑的微观结构。具有3-5纳米尺寸的纳米颗粒的钯被发现两者PVP /γ-Fe的表面上2 ö 3颗粒(6-10纳米)和内孔由它们形成。将Pd-PVP /γ-的Fe 2 ö 3已经证明在苯乙炔氢化改进的催化性能40℃和0.1MPa下的温和的条件下,相对于钯/γ-的Fe 2 ö 3以及使用聚乙二醇和果胶制备的类似催化剂。C-C三键的对Pd-PVP /γ-铁的氢化率2 ö 3达到2.8×10 -6 摩尔小号-1和苯乙烯选择性为92%。催化剂显示出弱的铁磁和软磁性能(M S  = 51 emu g -1,M r  = 5.4 emu g -1,H C  = 71 Oe),因此可以很容易地用外部磁体回收并重新用于至少进行11次,催化活性没有明显降低。

更新日期:2020-09-01
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