Lignin Depolymerization With Aldehyde Extraction for High Monomer Yield

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Solution Overview

Problem

Existing methods for lignin depolymerization in lignocellulosic biomass face challenges such as low yield, incompatibility with biorefinery strategies, and the need for harsh reaction conditions, leading to irreversible condensation and loss of hemicellulose and cellulose fractions.

Innovation Solution

A method involving the use of an aldehyde under acidic conditions with a lignocellulose-containing composition in an organic solvent, followed by separation and conversion of lignin fragments into monomers using hydrogenolysis, achieving near theoretical yields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If direct hydrogenolysis of native lignin is used, then lignin monomers are produced, but solid/solid separation of catalyst from cellulose residues is required which is impractical at industrial scale

Engineering Contradiction:
Improvelignin monomer productionVSAvoidcatalyst separation
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent extracts and removes the lignin fraction from the lignocellulosic biomass before hydrogenolysis, separating it from cellulose and hemicellulose. This allows the subsequent hydrogenolysis reaction to occur only on the extracted lignin in liquid phase, eliminating the need for solid/solid separation of catalyst from cellulose residues while maintaining high monomer production efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If harsh hydrogenolysis conditions are applied, then lignin depolymerization is achieved, but hemicellulose and cellulose fractions are lost or converted to sugar alcohols

Engineering Contradiction:
Improvelignin depolymerization efficiencyVSAvoidhemicellulose and cellulose loss
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent removes the lignin fraction through extraction before applying hydrogenolysis conditions. This selective removal protects the hemicellulose and cellulose fractions from degradation while still achieving efficient lignin depolymerization to monomers, as the harsh conditions are applied only to the extracted lignin in liquid phase

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the lignocellulosic biomass into separate fractions (lignin, cellulose, hemicellulose) through extraction. This segmentation allows independent processing of each fraction, enabling harsh hydrogenolysis conditions to be applied to lignin without affecting the integrity of cellulose and hemicellulose

Inventive Principle:
Principle #1Segmentation

3Productivity

If acid treatment and high temperature are used for lignin extraction, then lignin is removed from cellulose and hemicellulose, but severe and irreversible condensation of lignin occurs

Engineering Contradiction:
Improvelignin extraction efficiencyVSAvoidlignin structure stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent modifies the extraction parameters by using milder conditions (lower temperature and/or lower acid concentration) compared to conventional methods. This parameter change allows efficient lignin extraction while preventing severe condensation reactions that would otherwise occur under harsh conditions, thereby preserving the original lignin structure and its potential for high-yield monomer production

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method achieves significantly higher yields of lignin monomers, is compatible with biorefinery processes, and avoids harsh reactions, allowing for the production of valuable monomers and hemicellulose/cellulose derivatives.

Implementation Method 1

heating the composition of step a) under acidic conditions together with an aldehyde, boronic acid or a compound selected from 2-methoxypropene, dimethyl carbonate and 2,2-dimethoxypropane to achieve oligomers from lignin

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

converting the product of step c) into the monomers

Methodology Applied
Scientific EffectHydrogenolysis: Hydrogenation

Data Source

PatentEP3442938B1Production of monomers from lignin during depolymerisation of lignocellulose-containing composition
Publication Date: 2025.11.19 ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE (EPFL)
  • EP3442938B1 patent drawingFigure 1~2
  • EP3442938B1 patent drawingFigure 3a
  • EP3442938B1 patent drawingFigure 3b

AI summary

The present invention relates to a method for preparing monomers via depolymerisation from lignocellulose-containing biomass.