Two ways of catalytic depolymerization of native and isolated wood lignins are described: the peroxide delignification of hardwood (aspen, birch) and softwood (abies) in the medium of acetic acidwater over TiO 2 catalyst and the thermal dissolution of organosolv lignins (ethanol-lignin and acetone-lignin) in supercritical alcohols (ethanol and butanol) over solid Ni-containing catalysts. The catalyst TiO 2 in rutile modification has the higher activity in wood peroxide delignification at 100°C as compared to TiO 2 in anatase modification. The results of kinetic studies and optimization of the processes of peroxide depolymerization of hardwood (aspen, birch) and softwood (abies) lignins in the medium of acetic acidwater over catalyst TiO 2 (rutile) at mild conditions (≤ 100°C, atmospheric pressure) are compared. The catalyst TiO 2 initiates the formation of OH • and OOH • radicals from H 2 O 2 which promote the oxidative fragmentation of wood lignin. In this case, the peroxide depolymerization of softwood lignin, constructed from phenylpropane units of guaiacyl-type proceeds more difficult than the hardwood lignins, mainly containing syringyl-type units. The solid and soluble products of peroxide catalytic delignification of wood under the optimized conditions were studied by FTIR, XRD, GC-MS and chemical methods. Regardless of the nature of wood the cellulosic products have a structure similar to microcrystalline cellulose. The soluble products mainly consist of monosaccharides and organic acids. Aromatic compounds are present only in a low amount which indicates the oxidative degradation of aromatic rings of lignin phenylpropane units under the used conditions of wood catalytic delignification. The processes of thermal dissolution of acetone-lignin and ethanol-lignin from aspenwood in supercritical ethanol and butanol over Ni-containing catalyst (NiCu/SiO 2 , NiCuMo/SiO 2) are compared. The composition, structure and thermal properties of organosolv lignins were studied with the use of FTIR, GPC, 1 H-13 C HSQC NMR, DTA and elemental analysis. The influence of a composition of Ni-containing catalyst on the thermal conversion in supercritical butanol and ethanol of ethanol-lignin and acetone-lignin was established. The highest conversion of lignins (to 93% wt.) in supercritical alcohols and the highest yield of liquid products (to 90 % wt.) were achieved at 300 °C in the presence of catalyst NiCuMo/SiO 2. Scheme of green biorefinery of wood based on the use of non-toxic and low-toxic reagents (H 2 O 2 , H 2 O, acetic acid, ethanol, butanol) and solid catalysts (TiO 2 , NiCuMo/SiO 2) is suggested.

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The first green biorefinery of larch wood based on new methods of biomass fractionation on dihydroquercitin (DHQ), arabinogalactan (AG), microcrystalline cellulose (MCC) and soluble lignin (SL) is reported. The new green method of one-step isolation of DHQ and AG from larch wood by ethanol-water solution is described. The first results of kinetic studies and optimization of the process of extracted larch wood peroxide fractionation on MCC and SL in acetic acidwater medium in the presence of green TiO2 catalyst are presented. The products obtained from larch wood were characterized by FTIR, SEM, AFM, XRD and chemical methods. The scheme of larch wood biorefinery is suggested which integrates the described processes of biomass fractionation on DHQ, AG, MCC, SL and the yearly developed methods of polysaccharides processing to bioactive cupper and amino acidcontaining sulfated polymers along with the methods of nanoporous materials synthesis from lignin. All these methods use such non-toxic and less-toxic reagents, as water, ethanol, hydrogen peroxide, acetic acid, sulfamic acid, urea.

New method of cellulose sulfates obtaining from available and inexpensive raw material-aspen wood was developed. This method integrates catalytic peroxide delignification and sulfamic acid sulfation stadies. Such solvents as acetic acid and water were used for isolation of pure cellulose by wood peroxide delignification with TiO 2 catalyst. Low-aggressive and less-toxic sulfating agent-sulfamic acid-urea mixture was used for obtaining of cellulose sulfates.