Abstract

The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst.

Highlights

  • IntroductionThe development of base metal catalysts for sustainable and cost-effective processes is an actual and long standing goal of chemical research in academia and industry.[1,2,3] Among the different synthetic technologies, catalytic hydrogenations represent a versatile tool box for the preparation of numerous ne and bulk chemicals, fuels, and life science molecules.[4,5,6,7,8,9,10] Until today, on a practical scale these reactions mainly rely on precious metal-based catalysts,[4,5,6,7,8,9] as well as RANEY® nickel.[4,5,6,7,8,9,10] the availability and high price of precious metals, and selectivity problems and sensitivity of RANEY® Ni spurred interest towards alternative catalysts.[1,2,3,11,12,13,14,15,16,17,18] In this respect, reusable supported nanoparticles are attractive due to easy separation, accessibility of active sites, control of size, and prospect of mild reaction conditions.[15,16,17,18,19,20,21,22,23,24,25] Traditionally, supported metal nanoparticles are prepared by thermal (pyrolysis or calcination) or chemical reduction of the respective metal salts on heterogeneous supports.[19,20,21,22,23,24,25] Despite the synthesis of

  • metal organic frameworks (MOFs) proved to be suitable for gas separation and storage, and interesting catalytic applications have been realized,[27,28,29,30] especially via subsequent pyrolysis processes.[31,32,33,34]. Complementary to these materials, most recently we described the use of cobaltdiamine-dicarboxylic acid-based MOFs as precursors for the preparation of supported nanoparticles and single Co atoms, which exhibit excellent catalytic activity for reductive aminations.[35]

  • In continuation of our efforts to develop cost-efficient materials[36] for sustainable catalysis, we describe the expedient preparation of a cobalt-terephthalic acid MOF–carbon template, which forms a er pyrolysis graphene shell encapsulated Co3O4/Co particles

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Summary

Introduction

The development of base metal catalysts for sustainable and cost-effective processes is an actual and long standing goal of chemical research in academia and industry.[1,2,3] Among the different synthetic technologies, catalytic hydrogenations represent a versatile tool box for the preparation of numerous ne and bulk chemicals, fuels, and life science molecules.[4,5,6,7,8,9,10] Until today, on a practical scale these reactions mainly rely on precious metal-based catalysts,[4,5,6,7,8,9] as well as RANEY® nickel.[4,5,6,7,8,9,10] the availability and high price of precious metals, and selectivity problems and sensitivity of RANEY® Ni spurred interest towards alternative catalysts.[1,2,3,11,12,13,14,15,16,17,18] In this respect, reusable supported nanoparticles are attractive due to easy separation, accessibility of active sites, control of size, and prospect of mild reaction conditions.[15,16,17,18,19,20,21,22,23,24,25] Traditionally, supported metal nanoparticles are prepared by thermal (pyrolysis or calcination) or chemical reduction of the respective metal salts on heterogeneous supports.[19,20,21,22,23,24,25] Despite the synthesis of

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