Recovery of Valuable Chemicals from Wood Biomass by Thermo-chemical Conversion

Abstract

The logic and point for wood biomass utilization were surveyed, and then 3 kinds of pretreatment method developed by our group were introduced. In these methods, the direct saccharification is an efficient separation method by which cellulose fraction is saccharified with remaining lignin fraction as a solid. Next, we proposed a new method for converting thermo-chemically lignin fraction into valuable chemicals as a useful utilization of lignin. It was shown that only 3 organic acids (formic, acetic, and succinic acids) were successfully obtained in total yield of 45 wt% by oxidative decomposition of lignin for several minutes at 200°C in the presence of H₂O₂. Finally, a new method for direct conversion of wood biomass to chemicals was shown. The method was 2 step thermo-chemical processes of liquid phase oxidation by hydrogen peroxide and hydrothermal decomposition. Several kinds of valuable chemicals such as furfural and HMF were successfully recovered selectively in high yield by the oxidation with 0.5% H₂O₂ at 200°C and hydrothermal decomposition at 240°C. Thus, it was clearly shown that thermo-chemical conversion of wood biomass will be an attractive way to produce valuable chemicals.