Research ArticleMATERIALS SCIENCE

General and selective deoxygenation by hydrogen using a reusable earth-abundant metal catalyst

See allHide authors and affiliations

Science Advances  15 Nov 2019:
Vol. 5, no. 11, eaav3680
DOI: 10.1126/sciadv.aav3680
  • Fig. 1 Catalyst synthesis and characterization.

    (A) Synthesis of the catalyst by wet impregnation of commercially available charcoal with the bimetallic precursor complex I, followed by pyrolysis and reduction. (B) HAADF-STEM of the as-synthesized catalyst verifies the presence of homogeneously distributed metal nanoparticles with a mean diameter of 6.8 nm. (C) Detailed HAADF-STEM image in combination with EDX mapping. (D) EDX-based element mapping (Co, green; Ce, blue; O, red, P, orange) indicates that Co forms the nanoparticles and Ce is distributed over the whole carbon support. (E) XPS analysis confirms the presence of metallic cobalt (~20%) and cobalt oxide/hydroxide species (~80%). Ce is mainly present as Ce3+ (~ 90%) in addition to minor amounts of Ce4+ (~ 10%). a.u., arbitrary units.

  • Fig. 2 Selective hydrodeoxygenation of alcohols and carbonyl compounds I.

    [a] Reaction conditions: 0.5 mmol substrate, 15 or 35 mg of catalyst (1.8 mol % Co and 1.6 mol % Ce, or 4.2 mol % Co and 3.7 mol % Ce, respectively), 110° to 130°C, 5.0 MPa H2, 3 ml of methylcyclohexane, 20 hours (10 mg of Amberlyst 15 for halogenated substrates). [b] Reaction conditions: 0.5 mmol substrate, 50 mg of catalyst (6.1 mol % Co, 5.2 mol % Ce), 130°C, 6.0 MPa H2, 3 ml of methylcyclohexane, 20 hours [5 mol % Zn(OTf)2 for halogenated substrates]. Yields were determined by GC and GC-MS using n-dodecane as an internal standard. Isolated yields in parentheses.

  • Fig. 3 Selective hydrodeoxygenation of alcohols and carbonyl compounds II.

    [a] Reaction conditions: 1.0 mmol substrate, 100 mg of catalyst (6.1 mol % Co, 5.2 mol % Ce), 160°C, 6.0 MPa H2, 6 ml of methylcyclohexane, 20 mg of Amberlyst 15, 20 hours; *1 mmol substrate, 30 mg of catalyst (1.8 mol % Co, 1.6 mol % Ce), 110°C, 4.0 MPa H2, 6 ml of methylcyclohexane, 20 hours, no additive. [b] Reaction conditions: 1.0 mmol substrate, 70 mg of catalyst (4.2 mol % Co, 3.7 mol % Ce), 130°C, 5.0 MPa H2, 6 ml of ethanol, 20 hours. [c] Reaction conditions: 1.0 mmol substrate, 100 mg of catalyst (6.1 mol % Co, 5.2 mol % Ce), 160°C, 6.0 MPa H2, 6 ml of methylcyclohexane, 20 hours; diglyme was used as the solvent; 20 mg of Amberlyst 15 as additive; §5 mol % Zn(OTf)2 as additive. Yields were determined by GC and GC-MS using n-dodecane as an internal standard. Isolated yields are given in parentheses.

  • Fig. 4 Proposed reaction pathway regarding the hydrodeoxygenation of acetophenone.

  • Table 1 Catalyst screening.
    Embedded Image
    EntryMetal sourceSupportYield (%)
    Product AProduct B
    1Bimetallic complex ITiO26227
    2Bimetallic complex ICeO21569
    3Bimetallic complex Iγ-Al2O3621
    4Bimetallic complex IActivated charcoal8116
    5*Bimetallic complex IActivated charcoal98
    6Co(NO3)2 + Ce(NO3)3Activated charcoal18
    7Monometallic complex IIActivated charcoal10
    8Monometallic complex IIIActivated charcoal
    9Monometallic complex II + IIIActivated charcoal3251
    Reaction conditions: 0.5 mmol of substrate, 15 mg of catalyst (1.8 mol % Co, 1.6 mol % Ce), 100°C, 4.0 MPa H2, 3 ml of methylcyclohexane, 20 hours. *110°C reaction temperature; †1.8 mol % Co without Ce; ‡1.6 mol % Ce without Co. Yields were determined by GC and GC-MS using n-dodecane as an internal standard.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/11/eaav3680/DC1

    Supplementary Materials and Methods

    Fig. S1. SEM in combination with EDX analysis of the activated charcoal support and the active catalyst system.

    Fig. S2. Characterization of the active catalyst by HAADF-STEM analysis combined with energy-dispersed x-ray element maps.

    Fig. S3. HAADF-STEM combined with EELS.

    Fig. S4. XPS analysis of the Co-Ce catalyst.

    Fig. S5. Nitrogen physisorption measurements of the catalyst in comparison to the pure carbon support.

    Fig. S6. Structures of the different salen complexes.

    Fig. S7. Proposed reaction pathway for the hydrodeoxygenation of acetophenone.

    Fig. S8. XPS analysis of the different catalyst samples.

    Fig. S9. Recycling study.

    Fig. S10. Catalyst characterization after the fifth run.

    Table S1. Screening of reaction parameters—pyrolysis temperature.

    Table S2. Screening of reaction parameters—solvent.

    Table S3. Screening of reaction parameters—additive.

    Table S4. Hydrodeoxygenation of glycerol—screening of reaction temperature.

    Table S5. Catalyst screening for the hydrogenation of acetophenone.

    Table S6. Catalyst screening for the dehydration/hydrogenation of 1-phenylethanol.

    Table S7. Catalyst screening for the hydrogenation of styrene.

    Table S8. Catalyst comparison—hydrogenation of acetophenone.

    Table S9. Catalyst comparison—dehydration of 1-phenylethanol.

    Table S10. Catalyst comparison—hydrogenation of styrene.

    Table S11. Upscaling of the reaction.

    Table S12. Solvent deoxygenation study.

    Characterization of isolated products

    NMR Spectra

    References (3740)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Materials and Methods
    • Fig. S1. SEM in combination with EDX analysis of the activated charcoal support and the active catalyst system.
    • Fig. S2. Characterization of the active catalyst by HAADF-STEM analysis combined with energy-dispersed x-ray element maps.
    • Fig. S3. HAADF-STEM combined with EELS.
    • Fig. S4. XPS analysis of the Co-Ce catalyst.
    • Fig. S5. Nitrogen physisorption measurements of the catalyst in comparison to the pure carbon support.
    • Fig. S6. Structures of the different salen complexes.
    • Fig. S7. Proposed reaction pathway for the hydrodeoxygenation of acetophenone.
    • Fig. S8. XPS analysis of the different catalyst samples.
    • Fig. S9. Recycling study.
    • Fig. S10. Catalyst characterization after the fifth run.
    • Table S1. Screening of reaction parameters—pyrolysis temperature.
    • Table S2. Screening of reaction parameters—solvent.
    • Table S3. Screening of reaction parameters—additive.
    • Table S4. Hydrodeoxygenation of glycerol—screening of reaction temperature.
    • Table S5. Catalyst screening for the hydrogenation of acetophenone.
    • Table S6. Catalyst screening for the dehydration/hydrogenation of 1-phenylethanol.
    • Table S7. Catalyst screening for the hydrogenation of styrene.
    • Table S8. Catalyst comparison—hydrogenation of acetophenone.
    • Table S9. Catalyst comparison—dehydration of 1-phenylethanol.
    • Table S10. Catalyst comparison—hydrogenation of styrene.
    • Table S11. Upscaling of the reaction.
    • Table S12. Solvent deoxygenation study.
    • Characterization of isolated products
    • NMR Spectra
    • References (3740)

    Download PDF

    Files in this Data Supplement:

Stay Connected to Science Advances

Navigate This Article