Lignin: its functions and successive flow

Phenolic lignin-based polymers with structure-variable function have originally been designed, and a process has been developed for synthesizing them directly from native lignins. The key point of the process is to set up two different solvents, which are immiscible each other, for selective modification and separation of lignin and carbohydrates: hydrophobic solvent for hydrophobic lignin and hydrophilic solvent for hydrophilic carbohydrates. The native lignins, three dimensional network polymers, are subjected to selective modifications at the interface between both phases to give linear type polymers (lignophenols) composed mainly of 1,1-bis(aryl)propane type units, almost quantitatively. The process provides a new system for successively utilizing lignocellulosics in the molecular level.