Chemical and Enzymatic Routes for Lignocellulosic Bioproducts via Carbon Extension and Deoxygenation

Abstract

The past decade has witnessed a spectacular growth in bioproducts development due to the intense interest in creating a more diverse energy supply and a carbon neutral bioeconomy. Such a burgeoning bioeconomy has yet to be realized because the initial strategy to produce drop-in bioproducts is not economically competitive with respect to low-priced crude oil products. A recent paradigm has been to exploit high value functional and performance-advantaged bioproducts with unique properties and valuable propositions. This perspective describes strategies for the synthesis of such bioproducts through carbon–carbon coupling and hydrodeoxygenation chemistry. Emphasized are the mechanistic understanding of these new paths and the molecular interactions of substrates with the active sites and solvents in complex multifunctional catalysts that control the selectivity to desired products. Furthermore, various pathways for lignin valorization to polymers (for example, thermoplastics, thermosets, composites) are summarized for sustainable and integrated biorefineries. We have emphasized challenging issues of processes that produce furanic and other bioproducts. These are complimented with suitable biosystem-driven processes including enzymatic candidates both for cellulosic and lignin biorefineries.

Production of jet fuel cycloalkanes from 5‐(hydroxymethyl)furfural via cascade catalysis on Mg(Al)(Zr)O supported CuCo

“…[7][8][9] To meet the prerequisites of "drop-in" fuel replacements with high boiling point and high energy density, 5-HMF needs to be upgraded via C-C coupling reaction, extending carbon chain to > C 8 followed by hydrodeoxygenation reaction. [10][11][12][13][14][15] Dumesic group pioneers a threestep route to elongate carbon chain via aldol condensation reaction of 5-HMF with acetone, producing long chain hydrocarbons followed with hydrogenation and hydrodeoxygenation reactions. 16 For aldol condensation reaction, a large number of catalysts have been developed for promising yield of aldol adducts.…”

“…Among the platform molecules, 6 5‐(hydroxymethyl)furfural (5‐HMF) is one of the most promising compounds for the synthesis of a variety of value‐added ≤ C 6 chemicals and biomass‐derived fuels, including 2,5‐furandicarboxylic acid, levulinic acid, γ‐valerolactone, 2,5‐dimethylfuran, 2,5‐bishydroxymethylfuran, 1,6‐hexanediol, and n‐hexane via the reactions of hydrogenation, oxidation, hydrodeoxygenation, acidolysis, and/or rearrangement 7–9 . To meet the prerequisites of “drop‐in” fuel replacements with high boiling point and high energy density, 5‐HMF needs to be upgraded via C–C coupling reaction, extending carbon chain to > C 8 followed by hydrodeoxygenation reaction 10–15 . Dumesic group pioneers a three‐step route to elongate carbon chain via aldol condensation reaction of 5‐HMF with acetone, producing long chain hydrocarbons followed with hydrogenation and hydrodeoxygenation reactions 16 …”