Research ArticleChemistry

High performance of a cobalt–nitrogen complex for the reduction and reductive coupling of nitro compounds into amines and their derivatives

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Science Advances  17 Feb 2017:
Vol. 3, no. 2, e1601945
DOI: 10.1126/sciadv.1601945
  • Table 1 The results of nitrobenzene hydrogenation by H2 over different catalysts.

    The reaction conditions are as follows: nitrobenzene, 1 mmol; H2O, 15 ml; temperature, 110°C; H2 pressure, 3.5 bar; 1.5 hours.

    EntryCatalystCatalyst amount (mg)Molar ratio of nitrobenzene to CoConversion (%)Selectivity (%)
    1Co–Nx/C-600-AT404099.0>99
    2Cobalt phthalocyanine4018
    3Co–Nx/C-800-AT40589100>99
    4Co–Nx/C-900-AT4081870.8>99
    5N-C-800-AT40
    6*Co–Nx/C-800-AT4058947.1>99
    7*Co/N-C-800-BT401454>99

    *The reaction time was 0.5 hour.

    • Table 2 The results of nitrobenzene hydrogenation with H2 under different conditions.

      The reaction conditions are as follows: nitrobenzene, 1 mmol; Co–Nx/C-800-AT catalyst, 40 mg; and solvent, 15 ml.

      EntrySolventCatalystH2 pressure (bar)Temperature (°C)Time (hours)Conversion (%)Selectivity (%)
      1H2OCo–Nx/C-800-AT3.51101.5100>99
      2THFCo–Nx/C-800-AT3.51101.595>99
      3CH3CNCo–Nx/C-800-AT3.51101.596>99
      4EtOHCo–Nx/C-800-AT3.51101.5100>99
      5IsopropanolCo–Nx/C-800-AT3.51101.598>99
      6TolueneCo–Nx/C-800-AT3.51101.599>99
      7Ethyl acetateCo–Nx/C-800-AT3.51101.591>99
      8*H2OCo–Nx/C-800-AT11106100>99
      9*H2OCo–Nx/C-800-AT1401898.7>99
      10*†H2OPd/C1401868>99

      *Nitrobenzene (0.5 mmol) was used.

      †The same molar of Pd to Co in 40 mg of Co–Nx/C-800-AT.

      Supplementary Materials

      • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/2/e1601945/DC1

        fig. S1. Structure of cobalt phthalocyanine.

        fig. S2. TGA of the cobalt phthalocyanine/silica composite under a N2 atmosphere.

        fig. S3. Solid UV-Vis spectra of the samples after the pyrolysis of the cobalt phthalocyanine/silica composite at different temperatures.

        fig. S4. TEM images of the Co/N-C-SiO2-X samples.

        fig. S5. Particle size distribution of Co nanoparticles.

        fig. S6. Higher-resolution TEM images of the Co/N-C-AT-X samples.

        fig. S7. XRD patterns of the samples.

        fig. S8. Higher-resolution Co 2p XPS spectra.

        fig. S9. Higher-resolution C 1s XPS spectra.

        fig. S10. Higher-resolution N 1s XPS spectra.

        fig. S11. Reaction pathways of the reduction of nitrobenzene.

        fig. S12. Time course of the molar percentage of each compound during the hydrogenation of the nitrobenzene process.

        fig. S13. GC analysis of the hydrogenation of nitrobenzene over the Co/Nx-C-800-AT catalyst at low reaction temperatures.

        fig. S14. Molar percentage of the samples at three different temperatures.

        fig. S15. Plot of ln(Ct/C0) versus time for the reduction of nitrobenzene over the Co–Nx/C-800-AT catalyst at different temperatures.

        fig. S16. Tandem reaction of nitrobenzene with primary amines to produce imines.

        fig. S17. Reductive N-formylation of nitrobenzene to N-phenylformamide by formic acid.

        fig. S18. Synthesis of benzimidazole with o-dinitrobenzene and formic acid.

        table S1. The content of Co and N in the as-prepared catalysts.

        table S2. Recycling results for the Co–Nx/C-800-AT catalyst.

      • Supplementary Materials

        This PDF file includes:

        • fig. S1. Structure of cobalt phthalocyanine.
        • fig. S2. TGA of the cobalt phthalocyanine/silica composite under a N2 atmosphere.
        • fig. S3. Solid UV-Vis spectra of the samples after the pyrolysis of the cobalt phthalocyanine/silica composite at different temperatures.
        • fig. S4. TEM images of the Co/N-C-SiO2-X samples.
        • fig. S5. Particle size distribution of Co nanoparticles.
        • fig. S6. Higher-resolution TEM images of the Co/N-C-AT-X samples.
        • fig. S7. XRD patterns of the samples.
        • fig. S8. Higher-resolution Co 2p XPS spectra.
        • fig. S9. Higher-resolution C 1s XPS spectra.
        • fig. S10. Higher-resolution N 1s XPS spectra.
        • fig. S11. Reaction pathways of the reduction of nitrobenzene.
        • fig. S12. Time course of the molar percentage of each compound during the hydrogenation of the nitrobenzene process.
        • fig. S13. GC analysis of the hydrogenation of nitrobenzene over the Co/Nx-C-800-AT catalyst at low reaction temperatures.
        • fig. S14. Molar percentage of the samples at three different temperatures.
        • fig. S15. Plot of ln(Ct/C0) versus time for the reduction of nitrobenzene over the Co–Nx/C-800-AT catalyst at different temperatures.
        • fig. S16. Tandem reaction of nitrobenzene with primary amines to produce imines.
        • fig. S17. Reductive N-formylation of nitrobenzene to N-phenylformamide by formic acid.
        • fig. S18. Synthesis of benzimidazole with o-dinitrobenzene and formic acid.
        • table S1. The content of Co and N in the as-prepared catalysts.
        • table S2. Recycling results for the Co–Nx/C-800-AT catalyst.

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