Turning Lignin into Aliphatic Organic Chemicals in Gamma- Valerolactone: Advances into a Bioelectrorefinery

This investigation reports on the reductive electrochemical depolymerization and dearomatization of lignin using water/γ-valerolactone (GVL) as solvent system combined with sodium carbonate as electrolyte. GVL, derived from biomass, has often served as a solvent for biomass treatment, such as in the Organosolv process. Consequently, various strategies for biorefineries have emerged, utilizing GVL as a green platform, with a primary focus on its potential for the delignification of lignocellulosic biomass when combined with water and dilute acid. This investigation proposes the electrochemical depolymerization of lignin in GVL as a step toward the concept of a bioelectrorefinery, valorizing lignin conversion into aliphatic organic chemicals. Applying a current of −100 mA over 8 h resulted in the formation of sodium levulinate, sodium 4-hydroxyvalerate, sodium acetate, and sodium formate, as confirmed by liquid chromatography electrospray ionization high resolution mass spectrometry (LC-ESI-HRMS), nuclear magnetic resonance (NMR), and infrared (IR) spectroscopy. These findings enhance the understanding of GVL as a biomass-based platform, showcasing its potential as a medium in the conversion of lignin into valuable aliphatic organic chemicals. This study contributes to advancing the bioelectrorefinery concept and opens new avenues for utilizing renewable resources, envisioning the feasible future replacement of crude oil as the primary industrial source of carbon-based chemicals.