Stabilization strategies in biomass depolymerization using chemical functionalization

Abstract

A central feature of most lignocellulosic-biomass-valorization strategies is the depolymerization of all its three major constituents: cellulose and hemicellulose to simple sugars, and lignin to phenolic monomers. However, reactive intermediates, generally resulting from dehydration reactions, can participate in undesirable condensation pathways during biomass deconstruction, which have posed fundamental challenges to commercial biomass valorization. Thus, new strategies specifically aim to suppress condensations of reactive intermediates, either avoiding their formation by functionalizing the native structure or intermediates or selectively transforming these intermediates into stable derivatives. These strategies have provided unforeseen upgrading pathways, products and process solutions. In this Review , we outline the molecular driving forces that shape the deconstruction landscape and describe the strategies for chemical functionalization. We then offer an outlook on further developments and the potential of these strategies to sustainably produce renewable-platform chemicals.

Recent Advances in the Catalytic Depolymerization of Lignin towards Phenolic Chemicals: A Review

“…To date, most researchers primarily focused on the C−O−C ether bond cleavage in lignin due to its lower bond dissociation energy and higher amount than C−C bond . However, the design of catalytic systems aiming at further enhancement of monomer yield seems to be more captivating, which could achieve the fullest valorization of lignin.…”

Recent advances in starch‐based films toward food packaging applications: Physicochemical, mechanical, and functional properties

“…), and water (Khan, Bilal Khan Niazi, Samin, & Jahan, 2017). The most common plasticizer used glycerol is a waste byproduct and an economic burden of an ever‐growing biodiesel market, while other polyols and sugars can be produced from agricultural waste (Hu, Luo, & Li, 2014; Monteiro, Kugelmeier, Pinheiro, Batalha, & Cesar, 2018; Questell‐Santiago, Galkin, Barta, & Luterbacher, 2020). In most preparations of starch‐based films, starch is heated in water to its gelatinization temperature to break up the hydrogen bond‐supported crystal structure of the granules.…”

Pharmaceutically relevant (hetero)cyclic compounds and natural products from lignin-derived monomers: Present and perspectives

“…The utilization of building blocks originating from wood, for the synthesis of functional materials such as dyes ( Kühlborn et al., 2017 ), adhesives ( Wang et al., 2018 ), and polymers ( Isikgor and Becer, 2015 ; Sun et al., 2018b ; Questell-Santiago et al., 2020 ), as sustainable and renewable replacement of petrochemical building blocks has been accomplished and widespread activities are ongoing. More recently, a few groups have also focused on the production of high-value compounds such as natural products ( Alsarraf et al., 2020 ), pharmaceuticals ( Blondiaux et al., 2019 ), or biologically active compounds ( Elangovan et al., 2019 ) starting from wood.…”

“…Beside oxidation, various reductive methods have been introduced ( Song, 2020 ). The recently developed stabilization strategies ( Abu-Omar et al., 2020 ; Questell-Santiago et al., 2020 ), such as reductive catalytic fractionation (RCF) ( Renders et al., 2019 ) or aldehyde-assisted fractionation ( Shuai et al., 2016 ), start directly from lignocellulose and are able to achieve near-theoretical yields of monoaromatics and high selectivity for 4-propylguaiacol and 4-propyl syringol ( Song et al., 2013 ) as well as dihydroconiferyl ( Sun et al., 2018a ) and/or dihydrosinapyl alcohols ( Lan et al., 2018 ), whereas product distribution depends on the catalytic system and specific reaction conditions. Alternatively, these methods may also result in the formation of 4-(1-propenyl)-guaiacols and syringols as main products ( Galkin and Samec, 2014 ).…”