Green solvent “tames” stubborn wood waste, tailoring industrial lignin

The natural structure of lignin is too rigid and inactive to easily replace fossil-derived chemicals in manufacturing materials. A team from Beijing Forestry University has now found a way to chemically “loosen” this rigid structure using a Deep Eutectic Solvent (DES)—a biodegradable mixture that acts like a gentle molecular toolkit.

The study tests a DES composed of ethylenediamine and choline chloride at a molar ratio of 4:1. They have treated industrial alkali lignin under varying temperatures, times, and water contents to see how the structure evolved. Using advanced imaging techniques (2D NMR and FT-IR), they have observed a dual-action effect: at mild temperatures, the solvent introduced beneficial amine groups into the lignin, while at optimized conditions (160 ℃, 4 h, 80% water content), it precisely increased a specific type of reactive “handle”—the non-condensed G-type phenolic hydroxyl group, reaching a maximum of 1.168 mmol/g.

This innovation offers a practical and environmentally friendly pathway to replace toxic phenol in industrial adhesives, adding significant value to what is currently agricultural waste and reducing reliance on fossil fuels. The work titled “Tailoring the structure of industrial lignin using ethylenediamine/choline chloride-based deep eutectic solvent”, was published on Journal of Forestry Engineering (published on Mar. 25, 2026).