Cobalt nanocomposites on N-doped hierarchical porous carbon for highly selective formation of anilines and imines from nitroarenes. Issue 20 (18th July 2018)

• Record Type: Journal Article
• Authors: Song, Tao; Ren, Peng; Duan, Yanan; Wang, Zhaozhan; Chen, Xiufang; Yang, Yong
• Is Part Of: Green chemistry. Volume 20:Issue 20(2018)
• Page Start: 4629
• Page End: 4637
• Publication Date: 2018-07-18
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/c8gc01374h
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : A heterogeneous, active, and non-noble cobalt nanocomposite for selective synthesis of aniline derivatives and imines from nitroarenes is reported. Abstract : 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.