Catalytic depolymerization of lignin in supercritical ethanol

Area of Science:

• Catalysis
• Biomass Conversion
• Green Chemistry

Background:

• Lignin valorization is crucial for biorefineries.
• Soda lignin presents unique challenges due to its structure.
• Efficient depolymerization without charring is a key goal.

Purpose of the Study:

• To investigate the one-step valorization of soda lignin.
• To evaluate a CuMgAlOx catalyst in supercritical ethanol.
• To understand the role of ethanol in lignin depolymerization and repolymerization.

Main Methods:

• Supercritical ethanol treatment of soda lignin.
• Utilizing a CuMgAlOx catalyst.
• Product analysis using elemental analysis and 2D HSQC NMR.

Main Results:

• Achieved 23 wt% monomer yield, primarily aromatics, without char formation.
• Catalyst demonstrated high deoxygenation and low ring hydrogenation.
• Ethanol acted as a capping agent, preventing repolymerization via alkylation.

Conclusions:

• One-step soda lignin valorization in supercritical ethanol is feasible.
• CuMgAlOx catalyst enables efficient depolymerization and deoxygenation.
• Ethanol's alkylation mechanism is key to suppressing char and repolymerization.