Controlling the Product Selectivity of Peracetic Acid-Mediated Oxidative Lignin Depolymerization via a Deep Eutectic...

Area of Science:

• Biomass Conversion
• Green Chemistry
• Polymer Science

Background:

• Lignin's complex structure hinders selective depolymerization.
• Current methods often lack control over lignin derivatives.
• Efficient lignin valorization is crucial for biorefineries.

Purpose of the Study:

• To develop a selective lignin depolymerization process using deep eutectic solvents (DES).
• To control lignin's structural characteristics for targeted oxidation.
• To produce high-value phenolic acids and dicarboxylic acids.

Main Methods:

• Extraction of lignin using novel deep eutectic solvents (DES) like lactic acid/pyrazole and choline chloride/lactic acid.
• Controlled oxidative depolymerization of extracted oligomeric lignin using peracetic acid.
• Analysis of product selectivity based on DES choice and lignin source (Douglas fir, wheat straw).

Main Results:

• DES extraction yielded oligomeric lignin with controlled molecular weight and narrow size distribution.
• Oxidation of DES-extracted lignin selectively produced phenolic acids (Ph-COOH) and dicarboxylic acids (DCA).
• The choice of DES significantly influenced lignin structure, oxidation pathways, and product selectivity.

Conclusions:

• Deep eutectic solvent (DES) extraction offers a sustainable route to high-purity lignin.
• DES selection is critical for tailoring lignin structure and achieving selective oxidation to valuable products.
• This approach enhances the overall lignin biorefinery process by enabling high-value chemical production.