Electrochemical Depolymerization of Lignin in a Biomass‐based Solvent**

Abstract

Breaking down lignin into smaller units is the key to generate high value‐added products. Nevertheless, dissolving this complex plant polyphenol in an environment‐friendly way is often a challenge. Levulinic acid, which is formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin. Herein, levulinic acid was evaluated as a medium for the reductive electrochemical depolymerization of the lignin macromolecule. Copper was chosen as the electrocatalyst due to the economic feasibility and low activity towards the hydrogen evolution reaction. After depolymerization, high‐resolution mass spectrometry and nuclear magnetic resonance spectroscopy revealed lignin‐derived monomers and dimers. A predominance of aryl ether and phenolic groups was observed. Depolymerized lignin was further evaluated as an anti‐corrosion coating, revealing enhancements on the electrochemical stability of the metal. Via a simple depolymerization process of biomass waste in a biomass‐based solvent, a straightforward approach to produce high value‐added compounds or tailored biobased materials was demonstrated.

Electrocatalytic Reduction of Aldonic Acids to Aldoses on Gold Electrodes

“…Park et al and Pintauro et al reported on the electrochemical oxidation and reduction of glucose to gluconic acid and sorbitol. , Governo et al elaborated on the electrochemical oxidation of xylose to xylonic acid in an alkaline medium . Electrochemical degradation of lignin to high value-added products has been exploited since the 20th century and remains popular, − because of its high yield of aromatic compounds and carbohydrates, which can serve as feedstock for various platform chemicals. ,,, …”

Levulinic Acid-Based “Green” Solvents for Lignocellulose Fractionation: On the Superior Extraction Yield and Selectivity toward Lignin

“…Organosolv-lignin, obtained from a formic acid-acetone extraction, also presents such an intense band at the same wavenumber . The high content of CO in unconjugated ketone, carbonyl, and ester groups, can be an advantage in some applications, such as electrochemical uses, due to the enhancement of protonic and electrical conductivity and electrokinetic stability . Therefore, lignins enriched with CO functional groups, like the ones obtained in this work, might be suitable precursors for electrode materials.…”

Electrochemical Oxidation and Functionalization of Low‐Density Polyethylene

“…It is key to identify routes to increase dispersion of the polymer matrix, which may include the use of organic solvents and temperature, or a combination of both. Copper electrodes have been reported to degrade lignin biopolymer [22] . It is anticipated that improving the polymer‘s dispersion will increase the polymer‘s conversion efficiency.…”

“…Copper electrodes have been reported to degrade lignin biopolymer. [22] It is anticipated that improving the polymer's dispersion will increase the polymer's conversion efficiency.…”