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Kuznetsov, B. N.
Chesnokov, N. V.
Sudakova, I. G.
Garyntseva, N. V.
Kuznetsova, S. A.
Malyar, Yu. N.
Yakovlev, V. A.
Djakovitch, L.
2019-07-01T07:26:33Z
2019-07-01T07:26:33Z
2018-07
Kuznetsov, B. N. Green catalytic processing of native and organosolv lignins [Текст] / B. N. Kuznetsov, N. V. Chesnokov, I. G. Sudakova, N. V. Garyntseva, S. A. Kuznetsova, Yu. N. Malyar, V. A. Yakovlev, L. Djakovitch // Catalysis Today. — 2018. — Т. 309. — С. 18-30
09205861
https://www.sciencedirect.com/science/article/pii/S0920586117308155
http://elib.sfu-kras.ru/handle/2311/110783
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 acid – water over TiO2 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 TiO2 in rutile modification has the higher activity in wood peroxide delignification at 100°C as compared to TiO2 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 acid – water over catalyst TiO2 (rutile) at mild conditions (≤ 100°C, atmospheric pressure) are compared. The catalyst TiO2 initiates the formation of OH• and OOH• radicals from H2O2 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 aspen-wood in supercritical ethanol and butanol over Ni-containing catalyst (NiCu/SiO2, NiCuMo/SiO2) are compared. The composition, structure and thermal properties of organosolv lignins were studied with the use of FTIR, GPC, 1H - 13C 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/SiO2. Scheme of green biorefinery of wood based on the use of non-toxic and low-toxic reagents (H2O2, H2O, acetic acid, ethanol, butanol) and solid catalysts (TiO2, NiCuMo/SiO2) is suggested.
lignin
depolymerization
catalysts
bio-liquids
Green catalytic processing of native and organosolv lignins
Journal Article
Journal Article Preprint
18-30
31.21
2019-07-01T07:26:33Z
10.1016/j.cattod.2017.11.036
Институт цветных металлов и материаловедения
Кафедра органической и аналитической химии
Catalysis Today
Q1
Q1


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