Transitioning from crude oil to renewable sources of carbon-based chemicals is critical for advancing sustainable development. Lignin, a wood-derived biomacromolecule, holds great potential as a renewable feedstock, but efficient depolymerization and dearomatization methods are required to fully unlock its potential. In this investigation, we present a silver-catalyzed aqueous electrocatalytic method for the selective depolymerization and partial dearomatization of soda lignin under mild, ambient conditions. Utilizing a water/sodium carbonate solvent system and a silver electrode to mediate the electrochemical reduction, we achieved significant lignin depolymerization over reaction times ranging from 5 to 20 h. Analysis by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) revealed sodium levulinate, sodium acetate, and sodium formate as the main aliphatic products, alongside various aromatic species in the depolymerized lignin products (DL). This selective conversion of lignin into both valuable aromatic compounds and reactive aliphatic intermediates offers promising opportunities for further synthesis of a wide range of organic chemicals, contributing to the development of a more sustainable and circular economy.

The depolymerization of lignin represents a promising strategy for its efficient utilization as a precursor for industrial raw materials. However, achieving both high efficiency and environmental sustainability remains a significant challenge. In this study, we present an aqueous electrochemical approach employing nickel as an electrocatalyst, enabling both depolymerization and partial de-aromatization of Kraft lignin under mild reaction conditions. Using an aqueous sodium carbonate medium, room temperature and ambient pressure, we achieved lignin depolymerization over reaction times ranging from 5 to 20 h. Characterization by nuclear magnetic resonance (NMR) spectroscopy confirmed the formation of aliphatic products such as acetate and formate, while high-resolution mass spectrometry (HRMS) confirmed the formation of a wide range of phenolic compounds. The conversion of lignin into valuable aromatic and aliphatic compounds offers a promising pathway for the synthesis of a wide range of organic chemicals and their subsequent industrial utilization, thereby supporting the development of a more sustainable economy.

This investigation presents a one-pot electrochemical depolymerization of lignin, coupled with in-situ extraction, to enhance product recovery and process efficiency. Kraft lignin was dissolved in an aqueous sodium carbonate solution and covered with a methyl isobutyl ketone (MIBK) layer. The electrocatalytic reaction, conducted at −350 mA, facilitated lignin depolymerization, yielding a lignin-based bio-oil (LO) composed of a mixture of aromatic compounds, smaller aliphatic molecules such as alcohols, ketones, and acids, as well as sugar derivatives. Size exclusion chromatography confirmed a substantial reduction in molecular and dispersity, indicating effective and controlled lignin depolymerization. MIBK was chosen as an effective solvent for in-situ extraction due to its proven efficacy, reusability, and compliance with sustainable solvent guidelines. Preliminary tribological assessments demonstrated that, despite a higher coefficient of friction (COF) compared to conventional ester oils, LO provided comparable wear resistance, with minimal surface damage observed. Wear imaging further revealed stronger, more resilient surface interactions, suggesting LO’s potential as an eco-friendly lubricant with enhanced durability. These findings mark a critical advancement in lignin valorization, successfully overcoming challenges in product recovery from depolymerization processes and demonstrating its viability as a sustainable alternative to petroleum-based lubricants. Future studies will focus on optimizing formulation and fine-tuning performance to expand LO’s application potential in industrial lubrication