Convenient and Mild Epoxidation of Alkenes Using Heterogeneous Cobalt Oxide Catalysts**
Convenient and Mild Epoxidation of Alkenes Using Heterogeneous Cobalt Oxide Catalysts**
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DOI：
10.1002/anie.201310420
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发表时间：
2014-04-22
影响因子：
16.6
通讯作者：
Beller, Matthias
中科院分区：
文献类型：
--
作者：
Banerjee, Debasis;Jagadeesh, Rajenahally V.;Beller, Matthias
采用异相coxy - n /C （x=1,3; y=1,4）催化剂，过氧化叔丁基作为末端氧化剂，在温和条件下进行了芳烃和脂肪烯烃的环氧化反应。各种二苯乙烯和脂肪烯烃，包括可再生烯烃，以及维生素和胆固醇衍生物，成功地转化为相应的环氧化物，具有高选择性和高收率。钴氧化物催化剂可以循环使用五次而不会有明显的活性损失或结构变化。通过XRD、TEM、XPS和EPR分析表征催化剂，发现形成了不同尺寸的氧化钴纳米颗粒（Co3O4和一些CoO）和很少的大颗粒，具有金属Co核和氧化壳。在热解过程中，氮配体形成石墨烯型层，其中选定的碳原子被氮取代。
A general epoxidation of aromatic and aliphatic olefins has been developed under mild conditions using heterogeneous CoxOy-N/C (x=1,3; y=1,4) catalysts and tert-butyl hydroperoxide as the terminal oxidant. Various stilbenes and aliphatic alkenes, including renewable olefins, and vitamin and cholesterol derivatives, were successfully transformed into the corresponding epoxides with high selectivity and often good yields. The cobalt oxide catalyst can be recycled up to five times without significant loss of activity or change in structure. Characterization of the catalyst by XRD, TEM, XPS, and EPR analysis revealed the formation of cobalt oxide nanoparticles with varying size (Co3O4 with some CoO) and very few large particles with a metallic Co core and an oxidic shell. During the pyrolysis process the nitrogen ligand forms graphene-type layers, in which selected carbon atoms are substituted by nitrogen.