Separation of Components of Woody and Herbaceous Biomass Using Biphasic Organosolv Treatment and Catalytic Conversion of Products

Effective utilization of woody and herbaceous biomass requires separation into the components. Our group has developed an organosolv treatment using a water/1-butanol biphasic system as a separation technique under mild conditions. In this method, lignin solubilized under the treatment conditions was sequentially extracted into the butanol-rich phase, hemicellulose-derived compounds were dissolved in the water-rich phase, and cellulose was recovered as a solid. The rate-limiting step in the extraction process of lignin was revealed from a reaction engineering perspective. The solubilization rates of both lignin and hemicellulose were increased compared with a conventional homogeneous water/ethanol solvent system. Phenols were recovered after the catalytic reactions of solubilized lignin over iron oxide-based catalysts, which did not require an external supply of hydrogen. Combining this reaction with transalkylation using MFI-type zeolite catalyst was investigated through reaction tests using a model compound (p-propylphenol) to address the issue of producing various phenols. In addition, development of a simple solvent fractionation process, confirmation of the preservative activity of the fractionated lignin, and integration of lignin-derived phenols after alkaline oxidation into aromatic monomers combined with a bio-process were investigated.