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A new approach is being considered for obtaining microfibrillated cellulose with a low degree of polymerization by sulfuric acid hydrolysis with simultaneous ultrasonic treatment under mild conditions (temperature 25 °C, 80% power control). Samples of initial cellulose, MCC, and MFC were characterized by FTIR, XRF, SEM, DLS, and TGA. It was found that a high yield of MFC (86.4 wt.%) and a low SP (94) are observed during hydrolysis with ultrasonic treatment for 90 min. It was shown that the resulting microfibrillated cellulose retains the structure of cellulose I and has an IC of 0.74. It was found that MFC particles are a network of fibrils with an average size of 91.2 nm. ζ-potential of an aqueous suspension of MFC equal to −23.3 mV indicates its high stability. It is noted that MFC has high thermal stability, the maximum decomposition temperature is 333.9 °C. Simultaneous hydrolysis process with ultrasonic treatment to isolate MFC from cellulose obtained by oxidative delignification of spruce wood allows to reduce the number of stages, reduce energy costs, and expand the scope.

Sulfated cellulose derivatives are biologically active substances with anticoagulant properties. In this study, a new sulfated diethylaminoethyl (DEAE)-cellulose derivative has been obtained. The effect of a solvent on the sulfation process has been investigated. It is shown that 1,4-dioxane is the most effective solvent, which ensures the highest sulfur content in DEAE-cellulose sulfate under sulfamic acid sulfation. The processes of sulfamic acid sulfation in the presence of urea in 1,4-dioxane and in a deep eutectic solvent representing a mixture of sulfamic acid and urea have been compared. It is demonstrated that the use of 1,4-dioxane yields the sulfated product with a higher sulfur content. The obtained sulfated DEAE-cellulose derivatives have been analyzed by Fourier transform infrared spectroscopy, X-ray diffractometry, and scanning electron and atomic force microscopy, and the degree of their polymerization has been determined. The introduction of a sulfate group has been confirmed by the Fourier transform infrared spectroscopy data; the absorption bands corresponding to sulfate groups have been observed in the ranges of 1247-1256 and 809-816 cm-1. It is shown that the use of a deep eutectic solvent leads to the side carbamation reactions. Amorphization of DEAE-cellulose during sulfation has been demonstrated using X-ray diffractometry. The geometric structure of a molecule in the ground state has been calculated using the density functional theory with the B3LYP/6-31G(d, p) basis set. The reactive areas of DEAE-cellulose and its sulfated derivatives have been analyzed using molecular electrostatic potential maps. The thermodynamic parameters (heat capacity, entropy, and enthalpy) of the target sulfation products have been determined. The HOMO-LUMO energy gap, Mulliken atomic charges, and electron density topology of the title compound have been calculated within the atoms in molecule theory.

In this study, hemicelluloses of aspen wood (Pópulus trémula) were obtained by oxidative delignification in an acetic acid-water-hydrogen peroxide medium at temperatures of 70–100 °C and a process time of 1–4 h. The maximum polysaccharide yield of up to 9.68 wt% was reported. The composition and structure of the hemicelluloses were studied using a complex of physicochemical methods: gas and gel permeation chromatography, Fourier-transform infrared spectroscopy, 2D nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. The xylose, mannose, galactose, and glucose monomer units were identified in the hemicelluloses by gas chromatography. The weight average molecular weight Mw of the products determined by gel permeation chromatography was found to range within 8932–33,142 g/mol. The reported Fourier-transform spectra of the hemicelluloses contain all the bands characteristic of heteropolysaccharides; a weak lignin absorption signal in the spectra at 1500–1510 cm−1 is attributed to a minor content of phenolic fragments in the structure of the obtained hemicelluloses. The use of thermogravimetric analysis established that the hemicelluloses isolated from aspen wood are resistant against heating to temperatures of up to 90–100 °C and, upon further heating up to 400 °C, start destructing at an increasing rate. The antioxidant activity of the hemicelluloses was examined using the compounds that mimic free radicals (1,1-diphenyl-2-picrylhydrazyl) and hydroxyl radicals (salicylic acid). It was found that the activity of all polysaccharides in neutralizing DPPH and hydroxyl radicals is lower than the absorption capacity of vitamin C at all the tested concentrations (0.5, 2, and 5 mg/mL) and attains 81.7 and 82.9%, respectively.

In this study, hemicelluloses of aspen wood (

The analysis of the latest publications on the use of hydrolytic lignin, which is a large-tonnage waste of wood chemical processing, was carried out. In its original form, the hydrolytic lignin is used as fuel, fuel briquettes and pellets, binders and adhesives, organic fertilizers, fillers and enterosorbents. The processing of hydrolytic lignin by chemical and thermochemical methods allows to significantly expand the range of valuable products obtained from it. They are used in chemical, oil and gas and construction industries, metallurgy and other areas. Hydrolytic lignin is most widely used for the production of carbon sorbents. Recently, methods of thermochemical processing of lignin into porous carbon materials with the required texture and strength characteristics as well as into valuable organic products have been developed

The synthesis of galactoglucomannan sulfates using a sulfamic acid/urea mixture in 1,4-dioxane was studied for the first time. The effect of the galactoglucomannan sulfation time and temperature on the sulfur content in the galactoglucomannan sulfates was investigated. The introduction of sulfate groups into the galactoglucomannan structure was confirmed by the elemental analysis and Fourier transform infrared spectroscopy. The initial and sulfated galactoglucomannans were identified by X-ray diffraction, electron microscopy, and gel permeation chromatography. The thermal analysis has shown that sulfated galactoglucomannan, after the endothermic peak related to the moisture removal, yields a pronounced high-intensity exothermic peak with a maximum at 216 °C, and above 230 °C, the heat absorption effect (endothermic peak) characteristic of decomposition of the parent substance in the range of 230–335 °C is observed. According to the scanning electron microscopy data, the initial galactoglucomannan consists of irregular asymmetric particles with an average size from 400 to 900 µm, and the sulfated galactoglucomannan ammonium salt consists of particles 200–500 µm in size with different shapes. It was shown by gel permeation chromatography that, after the sulfation process, the main galactoglucomannan peak shifts toward higher molecular masses (from 24 to 26 kDa).

Experiments and calculations are used to determine the optimum parameters of the peroxide delignification of larch wood in the presence of MnSO4 catalyst that provides high yields of cellulose (44.3 wt %) with low residual lignin contents at a temperature of 100°C, an H2O2 content of 6 wt %, a CH3COOH content of 25 wt %, a LWR of 15, and a duration of 3 h The cellulose obtained under optimum conditions has a chemical composition of cellulose, 92.7 wt %; lignin, 0.6 wt %; and hemicellulose, 5.7 wt %. IRS and X-ray diffraction are used to determine that cellulose obtained from larch wood has a structure similar to that of industrial microcrystalline cellulose. The proposed catalytic approach allows cellulose to be obtained from larch wood with a minimal lignin content under mild conditions in one step and with a high yield, a degree of crystallinity of 0.8, and a crystallite size of 3.0 nm.

The process of abies ethanol lignin sulfation with sulfamic acid in 1,4-dioxane medium in the presence of urea was optimized by calculation methods. The influence of such factors, as the ratio of lignin/sulfating complex (L/SC), temperature and time of the sulfation process on the sulfur content in the resulting sulfated ethanol lignin and its yield, has been established. The variance analysis of the obtained mathematical models testifies their good predictive properties. The optimal conditions of abies ethanol lignin sulfation process, which provide the formation of water-soluble sulfated lignin with a high yield (to 100 % wt.) and sulfur content (up to 7.9 % wt.), have been established. They are: temperature of 95-100 °C, the ratio L/SC 1:2,3-1:2:9 and the time of the process 119-137 minutes

SSCI-VIDE+CDFA+LDJ:FRA; International audience; In the present work, a kinetic study and optimization of the process of spruce wood peroxide oxidation in “acetic acid–water” medium in the presence of suspended TiO2 catalyst at temperatures 70–100 °C were accomplished for the first time. The effect of wood species and organic solvent nature on the features of the processes of catalytic peroxide fractionation of wood biomass on microcrystalline cellulose and soluble organic products from lignin and hemicelluloses is described. Solid products of wood peroxide oxidation were characterized by FTIR, XRD, SEM, solid state 13C CP-MAS NMR and soluble products were identified by GC–MS. The experimental optimization of the process of birch wood oxidation by oxygen in “water–alkaline” medium in the presence of suspended Cu(OH)2 catalyst was carried out at temperature range 160–180 °C. The scheme of biorefinery of birch wood, based on catalytic oxidative fractionation of wood biomass with the production of pentosans, vanillin, syringaldehyde and levulinic acid was developed. The resulting products are in demand in many areas, including food, pharmaceutical, chemical, cosmetic industries, synthesis of new functional and biodegradable polymers.

Cellulose sulfates are important biologically active substances with a wide range of useful properties. The development of new methods for the production of cellulose sulfates is an urgent task. In this work, we investigated ion-exchange resins as catalysts for the sulfation of cellulose with sulfamic acid. It has been shown that water-insoluble sulfated reaction products are formed in high yield in the presence of anion exchangers, while water-soluble products are formed in the presence of cation exchangers. The most effective catalyst is Amberlite IR 120. According to gel permeation chromatography, it was shown that the samples sulfated in the presence of the catalysts KU-2-8, Purolit s390 plus, and AN-31 SO42− underwent the greatest degradation. The molecular weight destribution profiles of these samples are noticeably shifted to the left towards low-molecular-weight compounds with an increase in fractions in the regions Mw ~2.100 g/mol and ~3.500 g/mol, indicating the growth of microcrystalline cellulose depolymerization products. The introduction of a sulfate group into the cellulose molecule is confirmed using FTIR spectroscopy by the appearance of absorption bands at 1245–1252 cm−1 and 800–809 cm−1, which correspond to the vibrations of the sulfate group. According to X-ray diffraction data, amorphization of the crystalline structure of cellulose is observed during sulfation. Thermal analysis has shown that with an increase in the content of sulfate groups in cellulose derivatives, thermal stability decreases.

Spruce (Picea abies) wood hemicelluloses have been obtained by the noncatalytic and catalytic oxidative delignification in the acetic acid-water-hydrogen peroxide medium in a processing time of 3–4 h and temperatures of 90–100 °C. In the catalytic process, the H2SO4, MnSO4, TiO2, and (NH4)6Mo7O24 catalysts have been used. A polysaccharide yield of up to 11.7 wt% has been found. The hemicellulose composition and structure have been studied by a complex of physicochemical methods, including gas and gel permeation chromatography, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The galactose:mannose:glucose:arabinose:xylose monomeric units in a ratio of 5:3:2:1:1 have been identified in the hemicelluloses by gas chromatography. Using gel permeation chromatography, the weight average molar mass Mw of hemicelluloses has been found to attain 47,654 g/mol in noncatalytic delignification and up to 42,793 g/mol in catalytic delignification. Based on the same technique, a method for determining the α and k parameters of the Mark–Kuhn–Houwink equation for hemicelluloses has been developed; it has been established that these parameters change between 0.33–1.01 and 1.57–472.17, respectively, depending on the catalyst concentration and process temperature and time. Moreover, the FTIR spectra of the hemicellulose samples contain all the bands characteristic of heteropolysaccharides, specifically, 1069 cm−1 (C–O–C and C–O–H), 1738 cm−1 (ester C=O), 1375 cm−1 (–C–CH3), 1243 cm−1 (–C–O–), etc. It has been determined by the thermogravimetric analysis that the hemicelluloses isolated from spruce wood are resistant to heating to temperatures of up to ~100 °C and, upon further heating, start destructing at an increasing rate. The antioxidant activity of the hemicelluloses has been examined using the compounds simulating the 2,2-diphenyl-2-picrylhydrazyl free radicals.

The composition and physicochemical characteristics of polysaccharides extracted from spent liquors of catalytic and noncatalytic delignification of larch wood in the acetic acid-hydrogen peroxide medium were studied. The following were used as catalysts: (NH4)6Mo7O24, MnSO4, TiO2, and ZnSO4. The structure of polysaccharides was identified by FTIR and NMR spectroscopy. Their composition was established using gas chromatography, and the physicochemical characteristics were studied using gel permeation chromatography, scanning electron microscopy, thermogravimetric analysis, gas adsorption, and elemental analysis. It was shown that in the process of oxidative delignification, a significant amount of hemicelluloses and arabinogalactan passes into the spent liquor. The yield of polysaccharides was up to 16.9 wt%. Polysaccharides had a weight-average molecular weight of up to 22.9 kDa and a narrow molecular weight distribution.

International audience; Two alternative routes of softwood catalytic oxidative fractionation to cellulose products and fine chemicals are assessed.We suggested to use the process of larch wood peroxide oxidation in the medium acetic acid – water at temperatures 70–100 °C in the presence of soluble catalyst (NH4)6Mo7O24 to produce microcrystalline cellulose (35.0 wt% on wood), microfibrillated cellulose (7.5 wt% on wood) or nanocrystalline cellulose (3.7 wt% on wood) and low molecular weight organic compounds (20 wt% on wood). The developed process reduces the number of technological stages and increase an environmentally safety of nanocelluloses production from wood, compared to traditional technologies.Another suggested process of softwood (pine and larch) fractionation to vanillin (up to 4.7 wt% on wood) and cellulose (up to 34.6 wt% on wood) is based on wood oxidation by oxygen in water–alkaline medium at temperatures 160–180 °C in the presence of suspended catalyst Cu(OH)2. The further acid conversion of cellulose by 2 % H2SO4at 180 °C produces levulinic acid with the yield up to 9.7 wt % on wood.he integration of the processes of dihydroquercetin and arabinogalactan extraction isolation from larch wood, oxidation of extracted wood by oxygen to vanillin and cellulose in the presence of catalyst Cu(OH)2, acid catalyzed conversion of cellulose to levulinic acid and arabinogalactan hydrolysis over solid acid catalyst to arabinose and galactose leads to an increase in the number of target products.FTIR, XRD, SEM, AFM, solid state 13C CP/MAS and chemical methods were used for characterization of cellulose products. Organic compounds were identified by GC, HPLC and GC-MS methods.The two alternative schemes of larch wood catalytic oxidative biorefinery to produce nanocelluloses and fine chemicals have been developed.

The traditional method for obtaining microcrystalline cellulose (MCC) from wood raw material is multi-stage and it is based on the integration of environmentally hazardous processes of pulping and bleaching of cellulose and acid hydrolysis of amorphous part of cellulose. The paper describes an improved one-stage catalytic method of microcrystalline cellulose obtaining from softwood and hardwood based on peroxide delignification of wood in acetic acid-water medium under the mild conditions (100 °C, atmospheric pressure) in the presence of an environmentally safe solid catalyst TiO 2 . Experimental and mathematical optimization of the processes of MCC preparation by peroxide catalytic delignification of various types of wood was carried out. The following optimal modes of obtaining MCC with the yield 36.3–42.0 wt.% of abs. dry wood and residual lignin content ≤1.0 mas.%, hemicellulose ≤6.0 mas.% was established: for aspen – 5 wt.% H 2 O 2 , 25 wt.% CH 3 COOH, hydromodule = 10; for birch – 5 wt.% H 2 O 2 , 25 wt.% CH 3 COOH, hydromodule = 15; for abies – 6 wt.% H 2 O 2 , 30 wt.% CH 3 COOH, hydromodule = 15; for larch – 6 wt.% H 2 O 2 , 30 wt.% CH 3 COOH, hydromodule = 15.

Traditional processes of acid-catalyzed hydrolysis of wood are ineffective due to the low quality of formed glucose solutions contaminated with impurities that inhibit fermentation of glucose to ethanol. This problem grows during the hydrolysis of birch wood containing large amounts of hemicellulose. This work proposes producing quality glucose solutions using sulfuric acid (H2SO4, 80%) catalyzed hydrolysis at 25°C the cellulosic products formed during the catalytic peroxide delignification of birch wood. It is established that the composition of cellulosic products strongly affects the contents of glucose, xylose, and impurities inhibiting the enzymatic synthesis of bioethanol: furfural, 5-hydroxymethyl furfural, and levulinic acid. High yields (80.4–83.5 wt %) of glucose are achieved using cellulosic products produced by integrating the processes of sulfuric acid hydrolysis of hemicelluloses from birch wood and peroxide delignification of prehydrolyzed wood in the presence of catalysts: 2% H2SO4 and 1% TiO2. Concentration of inhibitors of enzymatic processes in these hydrolyzates is below the allowable limits. Hydrolyzates with maximum glucose content (86.4–88.5 wt %) and minimum concentration of inhibiting impurities produced by acid hydrolysis of cellulosic products treated with an 18% solution of NaOH. Gas chromatography, HPLC, and chromato-mass spectrometry are used to analyze the composition of hydrolyzates. Cellulosic products are examined by SEM, XRD, and chemical analysis.

A new method to obtain cellulose sulfates from available and inexpensive raw material—aspen wood was developed. This method integrates catalytic peroxide delignification and sulfamic acid sulfation stages. Solvents such as acetic acid and water were used for isolation of pure cellulose by wood peroxide delignification with TiO2 catalyst. Low-aggressive and less-toxic sulfating agent—sulfamic acid–urea mixture was used to obtain cellulose sulfates.

The traditional processes of catalytic acid hydrolysis of wood are low effective due to the low quality of the formed glucose solutions contaminated with admixtures that inhibit fermentation of glucose to ethanol. This is a particularly acute problem in hydrolysis of birchwood containing hemicelluloses in large proportions. In the present paper, quality glucose solutions are suggested to produce via sulfuric acid hydrolysis (80 % H 2 SO 4 , 25 °C) of cellulose products formed during catalytic peroxide delignification of birchwood. The composition of the cellulose products are established to affect considerably the content of glucose, xylose and admixtures (furfural, 5-hydroxymethylfurfural, levulinic acid) in glucose, which inhibit enzymatic synthesis of bioethanol. High yields of glucose (80.4–83.5 wt %) are achieved with cellulose products prepared by integrated processes of sulfuric acid hydrolysis of birchwood hemicelluloses and peroxide delignification of pre-hydrolyzed wood in the presence of catalysts 2 % H 2 SO 4 and 1 % TiO 2 . Concentrations of inhibitors of enzymatic processes are lower of the admissible levels in these hydrolyzates. The hydrolyzates with the maximal glucose content (86.4–88.5 wt %) and minimal concentration of inhibiting impurities are prepared by acid hydrolysis of cellulose products treated with 18 % NaOH. The hydrolyzate composition was studied using gas chromatography, HELC, chromatomass spectroscopy. IRS, XPS and chemical techniques were used for characterization of cellulose products.

A kinetic study and optimization of pine wood peroxide fractionation in the medium acetic acid–water over TiO2 catalyst were accomplished for the first time. Kinetic regularities and the product composition of green processes of catalytic peroxide fractionation of softwood (pine, abies, larch) and hardwood (aspen, birch) over 1 wt% TiO2 catalyst in the acetic acid–water medium were compared at the temperature range 70–100 °C. For all type of wood, the processes of peroxide delignification are described by the first order equations and their activation energies are varied at the range 76–94 kJ/mol. According to FTIR, XRD, SEM, NMR data, the cellulosic products of peroxide delignification have a structure similar to microcrystalline cellulose regardless of the nature of wood. Soluble products are presented by organic acid and monosaccharides. The scheme of green biorefinery of pine wood based on extractive-catalytic fractionation of wood biomass on microcrystalline cellulose, hemicelluloses, aromatic and aliphatic acids, monosaccharides, turpentine and rosin was developed. Green and non-toxic reagents and solid catalyst are used in the developed scheme of biorefinery.

800x600 Review of scientific publications and patents relating to the methods of producting of solid biofuels from plant waste was accomplished. It should be noted that most research were aimed at improving the existing methods for the production of briquettes and pellets from wood waste and expanding the raw material base for the production of solid biofuels through the use of non-wood plant biomass and municipal waste. It’s shown the use of environmentally friendly binders based on plant polymers for the production of solid biofuels it makes possible to increase the density, strength and water resistance of the briquettes. Normal 0 false false false RU X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Обычная таблица"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";}

It is established that the main regularities of the peroxide delignification of aspen wood in the temperature range of 70–100°С in the presence of dissolved (H2SO4) and solid (TiO2) catalysts are similar. With an increase of the temperature, the concentration of hydrogen peroxide and acetic acid, and the hydromodule (HM) values, as well as the duration of the process and the content of cellulose in the cellulose products, increase, while the content of the residual lignin decreases. Simultaneously, the total yield of cellulose products decreases independently of the nature of the catalyst. Delignification processes are satisfactory described by the first-order equation. A sufficiently high activation energy (88 kJ/mol in the presence of H2SO4 and 75 kJ/mol in the presence of TiO2) indicates the absence of significant external diffusion constraints in the selected conditions. The optimal conditions of obtaining cellulose products with a low content of residual lignin from aspen wood are found by the calculation methods. It is shown by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) that the structure of cellulose products obtained corresponds to the structure of industrial microcrystalline cellulose. In the optimal conditions, a high-quality cellulose product can be obtained in mild conditions (the temperature is 100°С, atmospheric pressure) by using a safer and technological TiO2 catalyst instead of a sulfuric acid catalyst.

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.

The conventional way of producing microcrystalline cellulose (MCC) from wood raw materials is multistage; it is based on integrating the environmentally hazardous processes of pulping and bleaching of cellulose and the acid hydrolysis of the amorphous phase of cellulose. This work describes an improved single-stage catalytic method for the production of MCC from softwood and hardwood that is based on the peroxide delignification of wood in an acetic acid–water medium under mild conditions (100°C, atmospheric pressure) in the presence of an environmentally safe TiO2 solid catalyst. The processes of MCC production via the peroxide catalytic delignification of various wood species are optimized experimentally and mathematically. The following optimum modes for the production of MCC with a yield of 36.3–42.0 wt % of absolutely dry wood, a residual lignin content of ≤1.0 wt %, and a hemicellulose content of ≤ 6.0 wt % are determined: For aspen: 5 wt % H2O2, 25 wt % CH3COOH, and a liquid/wood ratio of 10. For birch: 5 wt % H2O2, 25 wt % CH3COOH, and a liquid/wood ratio of 15. For silver fir: 6 wt % H2O2, 30 wt % CH3COOH, and a liquid/wood ratio of 15. For larch: 6 wt % H2O2, 30 wt % CH3COOH, and a liquid/wood ratio of 15.

The first green biorefinery of larch wood based on the fractionation of biomass into dihydroquercetin (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 was developed. The first results of kinetic studies and optimization of the process of extracted larch wood peroxide fractionation into MCC and SL in acetic acid–water medium in the presence of green TiO2 catalyst are described. The products obtained from larch wood were characterized by FTIR, NMR, XRD, AFM and chemical methods. The scheme of larch wood biorefinery is suggested which integrates the developed processes of woody biomass fractionation into DHQ, AG, MCC and SL. All developed methods use non-toxic and less-toxic reagents, such as water, ethanol, hydrogen peroxide and acetic acid.

SSCI-VIDE+CDFA+LDJ:CPI; International audience; The kinetic study of abies wood delignification by H2O2 in the medium acetic acid-water was first carried out in the presence of TiO2 catalyst under mild conditions: temperatures 70-100 degrees C, atmospheric pressure. The oxidative delignification process is described satisfactory by the first order equation in all temperature range. The rate constants varied between 0.80 and 12.3 9 10(-3) min(-1) and the activation energy was near 81 +/- 0.21 kJ mol(-1). The optimal parameters of the delignification process, providing the effective fractionation of abies wood on microcrystalline cellulose and soluble lignin, were established by experimental and numerical methods.