Targeted substituted-phenol production by strategic hydrogenolysis of sugar-cane lignin

de Albuquerque Fragoso, D. M., Goulart, H. F., Santana, A. E. G. and Jackson, S. D. (2021) Targeted substituted-phenol production by strategic hydrogenolysis of sugar-cane lignin. Biomass, 1(1), pp. 11-28. (doi: 10.3390/biomass1010002)

Abstract

In this work, a waste-derived lignin with abundant uncondensed linkages, using accessible solvents (acetone/water mixture) and low-cost catalysts showed successful depolymerization for the production of target molecules 4-ethylphenol, 4-propyl-2,6-dimethoxyphenol and 4-propyl-2-methoxyphenol. Lignin samples were obtained from sugar-cane bagasse residue by an organosolv process. Four alumina-based catalysts (Pt/Al2O3, Rh/Al2O3, Ni/Al2O3 and Fe/Al2O3) were used to depolymerize the sugar cane lignin (SCL) in an acetone/water mixture 50/50 v/v at 573 K and 20 barg hydrogen. This strategic depolymerisation-hydrogenolysis process resulted in the molecular weight of the SCL being reduced by half while the polydispersity also decreased. Catalysts significantly improved product yield compared to thermolysis. Specific metals directed product distribution and yield, Rh/Al2O3 gave the highest overall yield (13%), but Ni/Al2O3 showed the highest selectivity to a given product (~32% to 4-ethylphenol). Mechanistic routes were proposed either from lignin fragments or from the main polymer. Catalysts showed evidence of carbon laydown that was specific to the lignin rather than the catalyst. These results showed that control over selectivity could be achievable by appropriate combination of catalyst, lignin and solvent mixture.

• Item Type: Articles
• Additional Information: This research was funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico—Cnpq, Program Ciência sem Fronteiras—Doutorado Pleno no Exterior (GDE).
• Keywords: Biomass valorization, lignin, hydrogenolysis, heterogenous catalysis.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Jackson, Professor David and De Albuquerque Fragoso, Danielle Munick

Creator Roles

de Albuquerque Fragoso, D. M.: Funding acquisition, Validation, Formal analysis, Investigation, Writing – original draft, Writing – review and editing
Jackson, S. D.: Supervision, Project administration, Writing – review and editing

• Authors: de Albuquerque Fragoso, D. M., Goulart, H. F., Santana, A. E. G., and Jackson, S. D.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Biomass
• Publisher: MDPI
• ISSN: 2673-8783
• ISSN (Online): 2673-8783
• Published Online: 18 June 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Biomass 1(1): 11-28
• Publisher Policy: Reproduced under a Creative Commons License