Heterogeneous Catalytic Fractionation of Birch-Wood Biomass into a Microcrystalline Cellulose, Xylose and Enterosorbents.

The main components of the birch wood were fractionated into a microcrystalline cellulose, xylose and enterosorbents by an integration of heterogeneous catalytic processes of an acidic hydrolysis and a peroxide delignification of the wood biomass for the first time. The wood hemicelluloses were hydrolyzed to xylose at a temperature of 150°C in the presence of the Amberlyst® 15 solid acidic catalyst. Then, the lignocellulosic product of the wood hydrolysis was subjected to the peroxide delignification in the formic acid–water medium in the presence of the solid TiO2 catalyst with a formation of the microcrystalline cellulose (MCC) and the organic-soluble lignin. Yields of MCC and the organic-soluble lignin proved to be 64.5 and 11.5 wt % of a mass of the prehydrolyzed wood, respectively, under the determined optimal conditions (100°C, 7.2 wt % of Н2О2, 37.8 wt % of НСООН, LWR 15, and a duration of 4 h). The enterosorbents were prepared by a treatment of the organic-soluble lignin with 0.4% NaHCO3 or hot water. The sorption capacity of these enterosorbents was 97.7 and 236.7 mg/g according to methylene blue and gelatin, respectively. These values were significantly higher than those of the Polifepan commercial enterosorbent (44 and 115 mg/g, respectively). The products of the catalytic fractionation of the birch wood were characterized by physicochemical (FTIR, XRD, SEM, and GC) and chemical methods. [ABSTRACT FROM AUTHOR]