The search for active, inexpensive, and stable heterogeneous catalysts for organic transformation still remains challenging in both academia and industry. Herein, we present the facile fabrication of non-noble cobalt nanocomposites on N-doped hierarchical porous carbon derived from naturally renewable biomass together with Earth-abundant and low-cost cobalt salts. The whole preparation process is operationally simple and straightforward, cost-effective and environmentally benign and can be used in mass production for practical applications. The most active cobalt nanocomposite catalyst, that is, CoO_x@NC-800, demonstrated outstanding activity and excellent selectivity for the hydrogenation of functionalized nitroarenes to aniline derivatives with molecular hydrogen in water as a green medium. It also showed high activity for the direct and expedient synthesis of imines from the reductive amination of nitroarenes and aldehydes with excellent selectivity and good tolerance to a variety of functional groups. More importantly, a new straightforward one-pot cascade synthesis of benzimidazole was developed from the reductive amination of ortho-amino substituted nitrobenzene with aldehyde followed by sequential cyclization in a green and sustainable manner, further highlighting the utility of the catalyst. In addition, the catalyst can be easily separated for successive reuses without a significant loss in both activity and selectivity.

中文翻译：

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N掺杂的分级多孔碳上的钴纳米复合物，用于由硝基芳烃高度选择性地形成苯胺和亚胺

在学术界和工业界中，寻找用于有机转化的活性，廉价和稳定的非均相催化剂仍然是具有挑战性的。在本文中，我们介绍了从天然可再生生物质以及地球上丰富的低成本钴盐衍生的N掺杂分级多孔碳上轻松制备非贵金属钴纳米复合材料的方法。整个制备过程操作简单，直接，具有成本效益且对环境无害，可用于实际生产中的批量生产。活性最高的钴纳米复合催化剂，即CoO _x@ NC-800，在水中以分子氢为绿色介质时，对官能化的硝基芳烃加氢生成苯胺衍生物具有出色的活性和优异的选择性。从硝基芳烃和醛的还原胺化反应直接和方便地合成亚胺也显示出很高的活性，具有出色的选择性和对各种官能团的良好耐受性。更重要的是，通过邻位还原胺化开发了一种新的简单的一锅级联苯并咪唑合成方法-氨基取代的硝基苯用醛，然后以绿色和可持续的方式顺序环化，进一步突出了催化剂的实用性。另外，可以容易地分离催化剂以进行连续的再利用，而活性和选择性都没有显着损失。