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Publisher: London : RSC Publ. × Subject: Hydrogenation ×

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Now showing 1 - 3 of 3
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    Cobalt pincer complexes for catalytic reduction of nitriles to primary amines
    (London : RSC Publ., 2019) Schneekönig, Jacob; Tannert, Bianca; Hornke, Helen; Beller, Matthias; Junge, Kathrin
    Various cobalt pincer type complexes 1-6 were applied for the catalytic hydrogenation of nitriles to amines. Among these, catalyst 4 is the most efficient, allowing the reduction of aromatic as well as aliphatic nitriles in moderate to excellent yields. © 2019 The Royal Society of Chemistry.
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    Selective hydrogenation of fluorinated arenes using rhodium nanoparticles on molecularly modified silica
    (London : RSC Publ., 2020) Kacem, Souha; Emondts, Meike; Bordet, Alexis; Leitner, Walter
    The production of fluorinated cyclohexane derivatives is accomplished through the selective hydrogenation of readily available fluorinated arenes using Rh nanoparticles on molecularly modified silica supports (Rh@Si-R) as highly effective and recyclable catalysts. The catalyst preparation comprises grafting non-polar molecular entities on the SiO2 surface generating a hydrophobic environment for controlled deposition of well-defined rhodium particles from a simple organometallic precursor. A broad range of fluorinated cyclohexane derivatives was shown to be accessible with excellent efficacy (0.05-0.5 mol% Rh, 10-55 bar H2, 80-100 °C, 1-2 h), including industrially relevant building blocks. Addition of CaO as scavenger for trace amounts of HF greatly improves the recyclability of the catalytic system and prevents the risks associated to the presence of HF, without compromising the activity and selectivity of the reaction. © The Royal Society of Chemistry.
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    Highly active heterogeneous hydrogenation catalysts prepared from cobalt complexes and rice husk waste
    (London : RSC Publ., 2022) Unglaube, Felix; Schlapp, Janina; Quade, Antje; Schäfer, Jan; Mejía, Esteban
    The utilization and valorization of agricultural waste is a key strategy for the implementation of a sustainable economy to lessen the environmental footprint of human activities on Earth. This work describes the use of rice husk (RH) from agricultural waste to prepare a highly active catalyst for the reduction of nitro compounds. RH was impregnated with various cobalt complexes bearing N-donor ligands, then pyrolyzed and the resulting composite was etched with a base to remove the silica domains. The composition and morphology of the prepared materials were investigated by IR, AAS, ICP-OES, XRD, BET, XPS and SEM technics. The material showed excellent activity and selectivity in the hydrogenation of nitro groups in aromatic and aliphatic substrates. A remarkable selectivity towards nitro groups was found in the presence of various reactive functionalities, including halogens, carbonyls, borates, and nitriles. Apart from their excellent activity and selectivity, these catalysts showed remarkable stability, allowing their easy recovery and multiple reuse without requiring re-activation.