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Pd0.09Ce0.91O2-δ: A sustainable ionic solid-solution precatalyst for heterogeneous, ligand free Heck coupling reactions
Molecular Catalysis ( IF 3.9 ) Pub Date : 2017-10-09 , DOI: 10.1016/j.mcat.2017.09.022
Philani P. Mpungose , Neo I. Sehloko , Venkata D.B.C. Dasireddy , Narayanappa Mahadevaiah , Glenn E. Maguire , Holger B. Friedrich

A quick and easy method for the preparation of Pd2+ metal ion substituted in ceria, Pd0.09Ce0.91O2-δ solid solution oxide, is described. The Pd0.09Ce0.91O2-δ solid solution oxide was fully characterized by XRD, ICP-OES, BET, XPS, SEM, EDX, TEM, TGA and Raman spectroscopy. All characterization techniques strongly suggested that Pd2+ was successfully incorporated into the lattice structure of ceria. The effect of the reaction conditions on the catalytic properties of the Pd0.09Ce0.91O2-δ solid solution catalyst initially was studied in detail with the model Heck reaction of iodobenzene and methylacrylate to obtain optimum reaction conditions. The Pd0.09Ce0.91O2-δ solid solution catalyst then afforded substituted alkenes in good to excellent yields under these optimum reaction conditions. Steric and electronic effects were also studied, and were found to influence the catalytic activity. Characterization of the used catalyst suggests that Pd2+ in Pd0.09Ce0.91O2-δ is reduced in situ to Pd0 when employed in the Heck cross-coupling reactions. The catalyst was easily recovered by centrifuge and reused three times without significant loss of catalytic efficiency.



中文翻译:

Pd 0.09 Ce 0.91 O2 :可持续的离子固溶体预催化剂,用于非均相,无配体的Heck偶联反应

描述了一种制备二氧化铈中取代的Pd 2+金属离子的快速简便的方法,即Pd 0.09 Ce 0.91 O2 固溶体氧化物。通过XRD,ICP-OES,BET,XPS,SEM,EDX,TEM,TGA和拉曼光谱对Pd 0.09 Ce 0.91 O2 固溶体氧化物进行了全面表征。所有表征技术都强烈建议将Pd 2+成功地掺入二氧化铈的晶格结构中。反应条件对Pd 0.09 Ce 0.91 O2 催化性能的影响首先用碘代苯和丙烯酸甲酯的Heck模型反应对固溶催化剂进行了详细研究,以获得最佳反应条件。然后,在这些最佳反应条件下,Pd 0.09 Ce 0.91 O2 固溶体催化剂以良好或优异的收率提供了取代的烯烃。还研究了立体效应和电子效应,发现它们影响催化活性。所述用过的催化剂的表征表明,钯2+中的Pd 0.090.91 ö 2-δ减小原位与Pd 0当用于Heck交叉偶联反应时。催化剂可以很容易地通过离心回收,并且可以重复使用三遍,而不会显着降低催化效率。

更新日期:2017-10-09
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