Carboxylic Acids Production via Electrochemical Depolymerization of Lignin

Facing the challenge of lignin valorization is one of the unsolved key steps for a sustainable and economically feasible biorefinery. Several processes were developed with the aim of producing value-added compounds from lignin. Thermal, enzymatic, and catalytic processes represent common techniques for lignin valorization. However, expensive catalysts or enzymes and harsh conditions hampered the implementation of these methodologies on an industrial scale. Here, we propose the utilization of a simple swiss-roll electrochemical reactor for the production of valuable carboxylic acids. We showcase that production of phenolic compounds, such as vanillin, is hindered by the electrochemical mechanism. Additionally, electrochemical stability experiments of possible products showed high reactivity of vanillin against the low reactivity of mono- and dicarboxylic acids. Simultaneously, the electrochemical process leads to stable carboxylic acids with high yields of 6.4, 26.8, and 4.2% for oxalic, formic, and acetic acids, respectively, thus representing a competitive alternative to the catalytic and hydrothermal degradation process for the production of carboxylic acids.