Hydrothermal liquefaction of lignin

Lignin when depolymerized by a hydrothermal liquefaction process produces a range of phenolics. Such phenolics can be extracted as a monomer/oligomer phenolic-rich fraction and used as precursors or substitutes for epoxy or phenol-formaldehyde resins. This chapter summarizes the operating conditions required for the varying thermochemical technologies. A subset process of hydrothermal liquefaction termed solvolysis involves the use of solvents other than water. It is known that thermochemical, photochemical, and enzymatic degradation of lignin model compounds (LMCs) and technical lignin via reaction processes such as oxidation, hydrolysis, reduction, fragmentation, repolymerization, and rearrangement produces a wide spectrum of chemical products. The Derivative Followed by Reductive Cleavage (DFRC) method for lignin analysis is an approach that incorporates the selective bond breakage of β-O-4 bonds between lignin aromatics. This technique has been shown to produce high yields of depolymerization monomers in the order of 95% from LMCs with minimal product compound variation