Oxidative Catalytic Fractionation of Lignocellulosic Biomass under Non-alkaline Conditions
journal contributionposted on 2021-09-09, 14:08 authored by Hao Luo, Eric P. Weeda, Manar Alherech, Colin W. Anson, Steven D. Karlen, Yanbin Cui, Cliff E. Foster, Shannon S. Stahl
Biomass pretreatment methods are commonly used to isolate carbohydrates from biomass, but they often lead to modification, degradation, and/or low yields of lignin. Catalytic fractionation approaches provide a possible solution to these challenges by separating the polymeric sugar and lignin fractions in the presence of a catalyst that promotes cleavage of the lignin into aromatic monomers. Here, we demonstrate an oxidative fractionation method conducted in the presence of a heterogeneous non-precious-metal Co-N-C catalyst and O2 in acetone as the solvent. The process affords a 15 wt% yield of phenolic products bearing aldehydes (vanillin, syringaldehyde) and carboxylic acids (p-hydroxybenzoic acid, vanillic acid, syringic acid), complementing the alkylated phenols obtained from existing reductive catalytic fractionation methods. The oxygenated aromatics derived from this process have appealing features for use in polymer synthesis and/or biological funneling to value-added products, and the non-alkaline conditions associated with this process support preservation of the cellulose, which remains insoluble at reaction conditions and is recovered as a solid.
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syring aldehydeoxygenated aromatics derivedoxidative catalytic fractionationcarboxylic acids (<alkylated phenols obtainedalkaline conditions associatedprocess support preservation2 </ subreaction conditionsp </vanillic acidremains insolublepromotes cleavageprocess affordspossible solutionpolymeric sugarpolymer synthesisoften leadmetal colow yieldsisolate carbohydratescommonly usedbiological funnelingaromatic monomersappealing featuresadded products15 wt