Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (9): 1445-1452.DOI: 10.1016/S1872-2067(18)63132-8

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Single-step conversion of lignin monomers to phenol: Bridging the gap between lignin and high-value chemicals

Jiaguang Zhanga,b, Loris Lombardoc, Gökalp Gözaydina, Paul J. Dysonc, Ning Yana   

  1. a Department of Chemical and Biomolecular Engineering, National University of Singapore, 117585 Singapore;
    b School of Chemistry, University of Lincoln, Joseph Banks Laboratories, Green Lane, Lincoln, LN6 7DL, United Kingdom;
    c Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne(EPFL), CH-1015, Switzerland
  • Received:2018-06-28 Revised:2018-07-04 Online:2018-09-18 Published:2018-07-19
  • Contact: 10.1016/S1872-2067(18)63132-8
  • Supported by:

    This work was supported by the Ministry of Education in Singapore Tier-1 (R-279-000-479-112) and Tier-2 (R-279-000-462-112) Projects.

Abstract:

Transformation of lignin into high-value chemicals is hampered by the complexity of monomers obtained from lignin depolymerization. Here we report a strategy, composed of hydro-demethoxylation and de-alkylation reactions, that is able to chemically converge various lignin-derived phenolic monomers into phenol in a single-step. Using 2-methoxy-4-propylphenol as a model compound, Pt/C exhibited the best performance in hydro-demethoxylation reaction affording >80% 4-propylphenol from 2-methoxy-4-propylphenol, while H-ZSM-5 was identified as the most suitable catalyst for de-alkylation, achieving 83% yield of phenol from 4-propylphenol. Since the two catalysts operate under compatible conditions, combining the two catalysts to simultaneously promote both hydro-demethoxylation and de-alkylation reactions was achieved. Configuration of how to organize the catalysts is a critical parameter, where the physical mixture of the two was most effective, providing over 60% phenol from 2-methoxy-4-propylphenol in a single-step.

Key words: Lignin, Phenol, Zeolite, De-alkylation, Hydro-demethoxylation