Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Connor J. Cooper; Shahrina Alam; Vincent de Paul N. Nziko; Ryne C. Johnston; Alexander S. Ivanov; Zhongyu Mou; David B. Turpin; Alan W. RudieThomas J. Elder; Joseph J. Bozell; Jerry M. Parks
    Date: 2020
    Source: ACS Sustainable Chemistry & Engineering
    Publication Series: Scientific Journal (JRNL)
    Station: Southern Research Station
    PDF: Download Publication  (2.0 MB)


    Lignin is a highly abundant polyphenolic polymer that imparts mechanical strength to plant biomass. Transition-metal complexes can catalyze lignin oxidation to produce value-added products, but low catalytic efficiency has hampered their use in industry. Identifying the chemical and structural factors that govern catalytic activity is a prerequisite to rational design of catalysts with improved activity. Here, we combine computational and experimental approaches to investigate the mechanism of Co(salen)-catalyzed oxidation of the monomeric lignin models syringyl (S), vanillyl (G), and 4-hydroxybenzyl alcohol (H) to produce benzoquinone and benzaldehyde products. Experimentally, S oxidation to form dimethoxybenzoquinone proceeded efficiently with a Co(salen) catalyst coordinated by a pyridine ligand, but G and H did not undergo oxidation. Density functional theory calculations reveal that catalyst regeneration is energetically unfavorable in the presence of H, which prevents oxidation. In contrast, S readily facilitates catalyst regeneration. Formation of methoxybenzoquinone from G was achieved experimentally by adding bulky, noncoordinating bases. These findings provide a fundamental baseline for enhancing the activity of Co-Schiff base catalysts toward lignin-like molecules by adding sterically hindered nitrogenous bases or potentially by including a cocatalyst that promotes catalyst regeneration.

    Publication Notes

    • You may send email to to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Cooper, Connor J.; Alam, Shahrina; Nziko, Vincent de Paul N.; Johnston, Ryne C.; Ivanov, Alexander S.; Mou, Zhongyu; Turpin, David B.; Rudie, Alan W.; Elder, Thomas J.; Bozell, Joseph J.; Parks, Jerry M. 2020. Co(salen)-catalyzed oxidation of lignin models to form benzoquinones and benzaldehydes: A computational and experimental study. ACS Sustainable Chemistry & Engineering. 8(18): 7225-7234.


    Google Scholar


    shiff base, valorization, biomass, transition metal, density functional theory, catalysis

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page