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This article reviews a variety of literature-reported lignin isolation procedures that bring partly minor but important changes in the produced extracts. Five lignins were produced or acquired from various sources and characterized based on their thermal properties, molecular weights, chemical structures, as well as elemental compositions, which were all found to depend on their extraction methods. These extracts were then used to produce 5 different nanolignins using 2 similar facile solvent shifting methods with the difference being an alteration in pH. The nanolignins were characterized after the solvent shifting accounting for differences in pH. Nanolignins generated via only solvent exchange exhibited diameters ranging from 58 nm to 95 nm, while nanolignins precipitated using a solvent shifting method along with a shift in pH exhibited diameters ranging from 10 nm to 34 nm and dissimilar morphology, size, and surface charge. Those differences highlight the control options for nanolignin preparetion on the colloidal length scale. Understanding how different lignins can be used to generate nanolignins is mandatory for unlocking the possibilities of nanolignin for functional material applications. These nanolignins can be applied in construction, medical, and/or agricultural industries as renewable, biodegradable alternatives to existing polymer dispersions. [ABSTRACT FROM AUTHOR]

Sodium lignosulfonate (LS) was valorized to low molecular weight (Mw) fractions by combining solvothermal (SF) and catalytic hydrogenolysis/hydrogenation fragmentation (SHF) in a continuous flow system. This was achieved in either alcohol/H2O (EtOH/H2O or MeOH/H2O) or H2O as a solvent and Ni on nitrogen-doped carbon as a catalyst. The tunability according to the temperature of both SF and catalytic SHF of LS has been separately investigated at 150 °C, 200 °C, and 250 °C. In SF, the minimal Mw was 2994 g mol−1 at 250 °C with a dispersity (Đ) of 5.3 using MeOH/H2O. In catalytic SHF using MeOH/H2O, extremely low Mw was found (433 mg gLS−1) with a Đ of 1.2 combined with 34 mg gLS−1. The monomer yield was improved to 42 mg gLS−1 using dual catalytic beds. These results provide direct evidence that lignin is an unstable polymer at elevated temperatures and could be efficiently deconstructed under hydrothermal conditions with and without a catalyst. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new approach for valorization of monosaccharides derived from biomass into value added chemicals in a green and economically efficient manner by forming eutectic medium exclusively between reactants. Eutectic mixtures are emerging as an advantageous alternative to ionic liquids and have already found broad applications in biomass treatment; however they are preferably used only as low vapor pressure solvents. Increasing interest in eutectic solvents originates from their flexibility to adjust their properties to different biorefinery needs by simple variation of the compositions of eutectic mixtures. In this work, we made a first attempt to use a low molecular weight component, ammonium formate, to significantly change the physical properties of the eutectic mixtures and simultaneously increase their chemical reactivity. Using this approach, we valorised simple monosaccharides by turning them into fructopyrazines with high yields in their eutectic mixtures with ammonium formate. The research revealed a high sensitivity of the product yields to the temperature of the reaction and composition of the eutectic medium, as well as an important role of formate anions in product stabilization. [ABSTRACT FROM AUTHOR]