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A new method for extractive-catalytic fractionation of aspen wood to produce microcrystalline (MCC), microfibrillated (MFC), nanofibrilllated (NFC) celluloses, xylan, and ethanollignin is suggested in order to utilize all of the main components of wood biomass. Xylan is obtained with a yield of 10.2 wt.% via aqueous alkali extraction at room temperature. Ethanollignin was obtained with a yield of 11.2 wt.% via extraction with 60% ethanol from the xylan-free wood at 190 °C. The lignocellulose residue formed after the extraction of xylan and ethanollignin was subjected to catalytic peroxide delignification in the acetic acid-water medium at 100 °C in order to obtain microcrystalline cellulose. MCC is hydrolyzed with 56% sulfuric acid and treated with ultrasound to produce microfibrillated cellulose and nanofibrillated cellulose. The yields of MFC and NFC were 14.4 and 19.0 wt.%, respectively. The average hydrodynamic diameter of NFC particles was 36.6 nm, the crystallinity index was 0.86, and the average zeta-potential was 41.5 mV. The composition and structure of xylan, ethanollignin, cellulose product, MCC, MFC, and NFC obtained from aspen wood were characterized using elemental and chemical analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analyses, Gas chromatography (GC), Gel permeation-chromatography (GPC), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Dynamic light scattering (DLS), Thermal gravimetric analysis (TGA).

Reductive catalytic fractionation (RCF) has emerged as an effective lignin-first biorefinery strategy to depolymerize lignin into tractable fragments in high yields. Herein, we propose the RCF of spruce wood over a Ru/C bifunctional catalyst in the medium of ethanol and molecular hydrogen to produce monomeric phenolic compounds from lignin, polyols from hemicelluloses, and microcrystalline cellulose. This contribution attempts to elucidate the role of the Ru/C bifunctional catalysts characteristics. The results clarify the particular effect of the carbon support acidity, catalyst grain size, content and dispersion of Ru on the effectiveness of lignin and hemicelluloses extraction and the yields of liquid and gaseous products. The most efficient catalysts for RCF of spruce wood, providing high yields of the monomeric phenols, glycols, and solid product with content of cellulose up to 90 wt%, bear 3 wt% of Ru with a dispersion of 0.94 based on an acidic oxidized graphite-like carbon support Sibunit®, and having a grain size of 56–94 μm. The Ru/C catalysts intensify the reactions of hydrodeoxygenation of liquid products from lignin. The main phenolic monomers are 4-propyl guaiacol, 4-propenyl guaiacol, and 4-propanol guaiacol. We explored the effect of the process temperature and time on the yield and composition of the liquid, solid, and gaseous products of spruce wood RCF. The optimal trade-off between the yields of phenolic monomers (30.0 wt%). polyols (18.6 wt%) and the solid product containing 84.4 wt% of cellulose is reached at 225 °C and 3 h over the most acidic Ru/C catalyst.

Sulfation of birch wood xylan in 1,4-dioxane by sulfamic acid in the presence of urea at 90 and 100 °C was studied for the first time. The effect of the duration of xylan sulfation on the yield of xylan sulfates and the sulfur content in them was studied. It was found that the sulfur content in the obtained xylan sulfates increases from 12.5 to 17.5 wt% with an increase in the duration of sulfation from 2 to 4 hours. The structure of initial and sulfated xylan was studied by FTIR and NMR spectroscopy. The ease of purification of the obtained xylan sulfates from 1,4-dioxane in comparison with the purification of xylan sulfates obtained by sulfation in pyridine and N, N‑dimethylformamide is an advantage of the proposed method of xylan sulfation

γ-Valerolactone (GVL) is a valuable chemical compound known as a platform molecule. It is considered as an intermediate product for the synthesis of chemical compounds with high added value, components of motor fuels, and biopolymers. GVL is well established as an environmentally safe solvent, fuel additive, flavoring, and nutritional supplement. This review summarizes the latest advances in the development of catalytic ways of GVL synthesis from levulinic acid (LA), alkyl levulinates (ALs), and carbohydrates and plant polymers. Special attention is given to heterogeneous catalysts based on metals and metal oxides, which are more promising for practical application. Proposed mechanisms of the processes are considered in detail, and the prospect of using hydrogen-donor solvents in the processes of GVL production is discussed. Catalysts demonstrating the best catalytic properties are compared from the viewpoint of their productivity, an important parameter for industrial catalysis.

For the first time, tannin-lignin-formaldehyde and tannin-lignin-furfuryl organic gels were obtained on the basis of larch bark tannins and hydrolysis lignin by sol-gel condensation with formaldehyde and furfuryl alcohol. Their physico-chemical properties were studied by varying the content of lignin (from 5 to 30 wt%) and a fixed mass ratio of polyphenolic substances to the crosslinking reagent (1 : 1.5). With an increase in the lignin content the density of tannin-lignin formaldehyde gels decreases from 0.83 to 0.53 g/ cm3, and that of tannin-lignin-furfuryl gels is from 0.32 to 0.14 g / cm3. According to the FTIR data, the structures of tannin-lignin-formaldehyde and tannin-lignin-furfuryl gels are formed by aromatic fragments cross-linked with methylene and methylene-ether bridges. Scanning electron microscopy shows that the addition of appropriate amounts of lignin to tannins (up to 10 wt% when using formaldehyde and up to 20 wt% when using furfuryl alcohol) promotes the formation of gels with a more developed porous structure. In the case of tannin-lignin-formaldehyde gel, the specific surface area and sorption of methylene blue are 12 m2 / g and 43 mg / g and for tannin-lignin-furfuryl gel – 72 m2 / g and 114.5 mg/g, respectively. It was found that an increase in the lignin content in the gel composition over 20 wt.% is accompanied by the phase localization of lignin (precipitation), which reduces the strength of the resulting gel and reduces its specific surface area.

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

γ-Valerolactone (GVL), which is a valuable chemical compound and a platform molecule, is considered as an intermediate product for the synthesis of chemical compounds with high added value, components of motor fuels and biopolymers. GVL is successfully used as an environmentally friendly solvent, fuel additive, fragrance and food additive. This review summarizes recent advances in the development of catalytic methods for the production of GVL from levulinic acid (LA), alkyl levulinates (AL), carbohydrates and vegetable polymers. Particular attention is paid to heterogeneous catalysts based on metals and metal oxides, which are more promising for practical application. The proposed mechanisms of processes are considered in detail, and prospects of using hydrogen-donor solvents in the production of GVL are discussed. Catalysts with the best catalytic performance were compared in terms of their productivity, which is an important parameter for industrial catalysis.

A comparison of IR spectra and molecular weight distribution of arabinogalactan sulfates as sodium and ammonium salts obtained using various sulfating reagents was performed. According to the data, sulfated derivatives of arabinogalactan differ from each other in the nature of hydrogen bonds and molecular weight distribution. Using coagulological tests during activation of coagulation of platelet-poor human plasma in vitro, the anticoagulant properties of sulfated arabinogalactan derivatives in various salt forms differing in the preparation method, sulfation degree, and molecular weight were studied. It was found that the sample in the form of the sodium salt of sulfated arabinogalactan (SAG 1) with a sulfur content of 13.2 wt % and a polydispersity degree of 1.52 exhibited twofold greater anticoagulant activity than the sample in the form of the ammonium salt of sulfated arabinogalactan (SAG 2) with a sulfur content of 6.6 wt % and a polydispersity degree of 1.30. The antithrombin (aIIa) activity of the samples obtained by sulfation with a complex of pyridine and sulfuric anhydride (SAG 1) and a complex of sulfamic acid (SAG 2) was 23.42 ± 1.86 and 10.20 ± 1.50 U/mg, respectively; the value of the antifactor Xa activity of SAG 1 and SAG 2 was 2.13 ± 0.42 and 0.37 ± 0.08 U/mg; the aIIa/aXa ratio for SAG 1 and SAG 2 was 11 and 28, respectively. The antifactor Xa (aXa) activity of SAG, which is lower than that of unfractionated heparin (UFH), and a high aIIa/aXa activity ratio may contribute to less provocation of bleeding by SAG samples compared to UFH.

Pyrolysis of Kaa-Khemsky and Mezhegeisky coals was investigated with an increase in temperature to 900 °С with a change in pressure in the reactor by increasing the retention time of volatile substances in the pyrolysis zone at 600 °С and 640 °С. Liquid products of coal pyrolysis were extracted by hexane and benzene. The composition of liquid extracts was studied by chemical analysis, GC-MS and IR-spectroscopy, the solid product of extraction-by elemental analysis and scanning electron microscopy. It was established, that coal nature and pyrolysis conditions affect significantly on the yield of liquid, solid and gaseous products. Also, the retention time of volatile substances in pyrolysis zone influences on the yield of solid product (increases from 60 %wt to 73 % wt) and on composition of hexane and benzene soluble tar fractions. This is also facilitated by an increase in pressure in the reactor as a result of the release of volatile substances from coal in the pyrolysis zone

Lignin is a large-scale waste product of hydrolysis and the pulp-and-paper industries. The problem of lignin utilization is addressed by developing techniques for the comprehensive processing of wood biomass that are based on preliminary catalytic fractionation into its key components, which are subsequently used for obtaining target products. Hemicelluloses of larch wood are known to undergo effective depolymerization (~95 wt %) in ethanol at 250°C. Using hydrogen in combination with a catalyst enables us to increase the lignin conversion to 61 wt %, with 47 wt % of the cellulose left in the solid residue. The highest lignin conversion (67 wt %) is achieved using formic acid, but there is undesirable cellulose depolymerization (conversion, 66 wt %) under these conditions. The main monomer products of the catalytic conversion of lignin are 4-propenylguaiacol and 4-propylguaiacol. The content of 4-propenylguaiacol among the liquid products obtained using ethanol and formic acid as reducing agents can be as high as 36 and 33 rel %, respectively. The content of 4-propylguaiacol among the liquid products obtained using hydrogen grows to 33 rel % when a catalyst is used. This work describes the first study of the catalytic fractionation of larch wood in supercritical ethanol in the presence of the bifunctional 3%Ru/C catalyst containing acidic groups. The aim is to identify the effect of the catalyst and the nature of the hydrogen donor (ethanol, H2, or formic acid) on the yield and composition of the product.

The porous structure and sorption properties of carbon materials produced by thermochemical activation of the bast of birch bark with potassium hydroxide at 800°C have been studied. The effect of the amount of introduced KOH on the specific surface area of carbon materials obtained from bast was established. The selection of the optimal conditions for the preliminary carbonization of the bast was carried out, providing after thermal activation with KOH the formation of porous carbon materials with a specific surface of up to 2469 m2 g–1, a total pore volume of up to 1.085 cm3 g–1, a micropore volume of up to 0.84 cm3 g–1, and an average size pores less than 2.0 nm. It is shown that preliminary carbonization of bast at 500–580°С and subsequent activation with KOH at 800°С shifts the pore distribution in the resulting carbon materials towards smaller sizes (0.5–1.0 nm). It was found that carbon materials produced from heat-treated birch bast have a sorption activity for benzene, which exceeds the performance of foreign industrial carbon sorbents by 2.4 times and domestic active carbons of SKT-3 and SKT-10 grades by 3.4 times. Pre-carbonization of birch bast increases the yield of porous carbon materials by a factor of 3–4 compared to their yield when using untreated bast.

It was found that when betulin is sulfated with chlorosulfonic acid in pyridine medium, 3,28-disulfate of betulin is formed in a stable salt form. Under optimal synthesis conditions: temperature 70 °C, duration 2 hours, molar ratio betulin / chlorosulfonic acid 4.0, betulin is completely converted into betulin 3.28-disulfate. The structure and composition of betulin 3,28-disulfate were confirmed by elemental analysis, IR, Raman and 13C NMR spectroscopy. Betulin 3,28-disulfate was isolated both in the form of an unstable H + -form and in a stable forms of sodium and pyridinium salts. Sodium salt of 3,28-disulfate is a needle-like crystals collected in cobweb-like aggregates. The sodium salt of 3,28-disulfate has mycellar properties, the critical concentration of mycellar formation is 0.23 mmol / L.

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 regularities of thermocatalytic transformation of pine ethanol lignin in supercritical ethanol in the presence of catalysts NiCu/SiO₂ and NiCuMo/SiO2 in the temperature range 250–400 °C were established. The composition and structure of ethanol lignin, liquid and solid products of its conversion were studied by methods of elemental analysis and gel-permeating chromatography (GPC). The composition of gaseous products – by method of gas chromatography. At the process temperature of 250 °C the catalysts do not have a significant effect on conversion of ethanol lignin. The maximal yield of liquid products (83.5 wt. %) was obtained at temperature 300 °C in the presence of catalyst NiCuMo/SiO₂ containing 8.8 wt. % of molybdenum. At temperature 350 °C NiCu/SiO₂ and NiCuMo/SiO2 catalysts contribute to the almost complete conversion of ethanol lignin into liquid and gaseous products, and the yield of solid products does not exceed 1 wt. %. In liquid products of catalytic conversion there is a decrease in the atomic ratio of O/C and the increase of H/C atomic ratio as compared to initial ethanol lignin due to catalytic intensification of reactions of deoxygenation and hydrogenation of lignin and products of its depolymerization. According to GPC data on the curves of molecular mass distribution (MMD) of liquid products of thermocatalytic conversion of ethanol lignin at 300 °C there are peaks with highs at 160 and 380 Da, probably related to guiacyle monomers and dimmers, respectively. From the comparison of MMD of liquid products obtained by ethanol lignin depolymerization at 300 °C over catalysts NiCu/SiO₂ and NiCuMo/SiO₂ it follows, that the introduction of molybdenum in the catalyst promotes the formation of monomeric guaiacyl products

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

Methods of organic and carbon xerogels synthesis based on the use of condensed tannins isolated from abies bark were developed. Organic gels were synthesized by sol-gel condensation of tannins with formaldehyde in a solution of ethanol in the presence of catalysts (NaOH or HCl). The final gelation products were dried by alternating low (-18 – -40 °C) and room temperature to obtain tanninformaldehyde (TF) xerogels. FTIR study indicates that the formation of xerogels was accompanied by crosslinking reactions mainly due to the formation of carbon-carbon and alkyl ether bonds. Using the method of thermogravimetry, it was found that organic TF xerogels are thermally stable up to a temperature of 295 °C and they are resistant to ignition in air at temperatures up to 600 °C and can be used as thermo- and fire-retardant materials. Carbon tannin-formaldehyde xerogels were obtained by carbonization of organic xerogels at 800 °C in an argon atmosphere. The porous structure and surface morphology of organic and carbon xerogels was studied by BET- and SEM–methods. A significant development of the specific surface area (to 483–524 m2/g)as a result of the organic xerogels carbonization was established. Using SEM, it was shown that in carbon gels a spatially cross-linked structure of polymer chains consisting of 5-10 nmsized globule particles forming nanometer-sized pores is retained

The sulfation of ethanol lignin of abies wood by sulfamic acid–urea mixture in N,N-dimethylformamide (DMF) medium was studied for the first time. The effect of the duration of lignin sulfation process on the yield and sulfur content in resulted lignin sulfates was studied. It was shown that the reaction of ethanol lignin sulfation begins and ends in a homogeneous medium. At temperature 100 °C, the sulfur content in lignin varies from 5.4 to 6.8% mass, depending on the process time. The introduction of sulfate groups into the lignin structure was confirmed by FTIR and 2D NMR spectroscopy. It was found that both alcohol and phenolic hydroxyl groups of lignin enter the sulfation reaction. The molecular weight distribution of sulfated ethanol lignin was determined by gel permeation chromatography. The optimized method of synthesis allows to obtain sulfated ethanol lignin with low polydispersity (1.31) and narrow molecular weight distribution (3.25–3.75 kDa).

Lignin is a bulky waste of the hydrolysis and paper-pulp industry. To solve the problem of its utilization, approaches to deep processing of wood biomass are being developed; they are based on a preliminary catalytic fractionation of wood biomass into main components, which are processed into target products. For the first time, the reductive catalytic fractionation of larch was studied in a supercritical ethanol medium in the presence of 3%Ru/С bifunctional catalyst containing acid groups. The goal of the study was to reveal the effect of the catalyst and features of a hydrogen donor (ethanol, H2, formic acid) on the yields and composition of the products. It was shown that wood hemicelluloses efficiently (ca. 95 wt.%) depolymerize to ethanol at 250 °С. The use of hydrogen in the presence of the catalyst makes it possible to increase the conversion of lignin to 61 wt.% with retaining 47 wt.% cellulose in a solid residue. The maximum conversion of lignin equal to 67 wt.% was obtained in the presence of formic acid; however, the indicated conditions lead to undesirable depolymerization of cellulose (the conversion of 66 wt.%). The main monomeric products of lignin conversion on the catalyst are propenylguaiacol and propylguaiacol. In the liquid products obtained with ethanol and formic acid as the reductants, the content of propenylguaiacol reaches 36 and 33 rel.%, respectively. In the products obtained with hydrogen, the content of propylguaiacol increases to 33 rel.% in the presence of the catalyst.

The new method of producing of microfibrillated cellulose (MFC) from spruce wood was described. This method includes the stages of cellulose obtaining by peroxide delignification of wood in the medium “acetic acid-water-H2SO4 catalyst” and cellulose acid hydrolysis, ultrasonic treatment, and freeze drying. The structure of cellulosic products was studied by FTIR, XRD, SEM, AFM, dynamic light scattering methods. The particle size of final cellulosic products is characteristic of microfibrillated cellulose according to the TAPPI Standard WI 3021 classification. The particles of the MFC are characterized by a rather high surface charge, and its aqueous suspension showed a high colloidal stability for a long time. According to the AFM data the surface of the microfibrillated cellulose film is formed by homogeneous spherical particles with a diameter about 80 nm and does not contain external inclusions. The new method of obtaining MFC from spruce wood is less energy-consuming and more environmentally friendly compared to traditional technologies due to single-stage production of high quality cellulose without the use of sulfur- and chlorine containing delignifying agents, increased pressure and high water consumption.

For the first time water soluble copper-containing polymers based on sulfated ethanol lignin of abies wood were obtained by the method of ion exchange. Their composition and structure were studied with the use of elemental and chemical analysis, infrared spectroscopy (IR), atomic absorption, electron paramagnetic resonance (EPR). The absence of nitrogen for copper cations in the resulting polymer indicates the complete substitution of ammonium cations in the ammonium salt of sulfated ethanol lignin. In EPR spectrum of copper-containing sulfated ethanol lignin there is a superposition of two signals. One of them belongs to isolated Cu2+ ions, the other to exchange-bound Cu2+ ions in salt-like compounds. The integral intensity of signal of isolated Cu2+ ions (anisotropic signal) and exchange-bound ions (isotropic signal) depends on the copper content in the polymer

Methods have been developed for the preparation of enterosorbents by treating crushed abies bark with the 1.5% aqueous of NaOH solution or by extraction with hexane. It was found that all obtained enterosorbents have good sorption properties with respect to gelatin and methylene blue. The highest sorption activity for methylene blue was shown by a sample, obtained by extraction of abies bark with hexane (97.0 mg/g), and for gelatin sorption activity – a sample, obtained by treatment of abies bark with alkali (225.0 mg/g). It was found that the enterosorbent, obtained by treatment of abies bark with alkali solution both at a dose of 0.15 g per kg of animal weight (g/kg) and at a dose of 0.20 g/kg and the enterosorbent, obtained by extraction of abies bark with hexane at a dose of 0.20 g/kg, have the highest efficiency for the treatment and prevention of acute experimental Escherichiosis. From the considered methods of obtaining enterosorbents from abies bark for the treatment and prevention of gastrointestinal infections of animals, it is recomended to use a method based on treatment of abies bark with alkalai solution and apply the drug in a dose of 0.15 g/kg

Carbon tannin-lignin-formaldehyde (TLF) gels were obtained for the first time by carbonization of organic xerogels synthesized by sol-gel condensation of formaldehyde with polyphenolic substances isolated from abies wood and bark – ethanol lignin and condensed tannins. The effect of the mass ratio of the tannins/lignin (T/L) components in the range 1:0 – 1:2 on the specific surface areas, porous volume, apparent density, and microstructure of carbon tannin-lignin-formaldehyde gels has been studied. It was found that the density of the carbon gels increases from 0.52 to 0.60 g/cm3 with a rises in the T/L ratio from 1:0 to 1:0.2 and 1:0.5 in the initial gel and then decreases to 0.20 and 0.13 g/cm3 with an increase in the lignin content to T/L ratios of 1:1 and 1:2, respectively. The study of the porous structure of carbon gels by the BET method showed that the carbon TLF gel obtained at a T/L ratio 1:2 is characterized by the highest specific surface area (538 m2/g). Using scanning electron microscopy, the structures of TF and TLF carbon gels have been studied. It has been established that the size of globular particles has a decisive influence on the structure of gels. The size of the globule particles increases with increasing of lignin content in the composition of the tannin-lignin-formaldehyde gel that leads to the formation of a less ordered structure of the carbon gel. The porous structure of TLF carbon gels obtained from abies polyphenolic substances can be regulated by varying the ratio of tannins:lignin. The obtained carbon gels can be used as sorbents and catalyst supports

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.

Noble metal-based catalysts are widely used to intensify the processes of reductive fractionation of lignocellulose biomass. In the present investigation, we proposed for the first time using the inexpensive NiCuMo/SiO2 catalyst to replace Ru-, Pt-, and Pd-containing catalysts in the process of reductive fractionation of abies wood into bioliquids and cellulose products. The optimal conditions of abies wood hydrogenation were selected to provide the effective depolymerization of wood lignin (250 °C, 3 h, initial H2 pressure 4 MPa). The composition and structure of the liquid and solid products of wood hydrogenation were established. The NiCuMo/SiO2 catalyst increases the yield of bioliquids (from 36 to 42 wt%) and the content of alkyl derivatives of methoxyphenols, predominantly 4-propylguaiacol and 4-propanolguaiacol. A decrease in the molecular mass and polydispersity (from 1870 and 3.01 to 1370 Da and 2.66, respectively) of the liquid products and a threefold increase (from 9.7 to 36.8 wt%) in the contents of monomer and dimer phenol compounds were observed in the presence of the catalyst. The solid product of catalytic hydrogenation of abies wood contains up to 73.2 wt% of cellulose. The composition and structure of the solid product were established using IRS, XRD, elemental and chemical analysis. The data obtained show that the catalyst NiCuMo/SiO2 can successfully replace noble metal catalysts in the process of abies wood reductive fractionation into bioliquids and cellulose.

The new process of abies ethanol lignin sulfation by a low-toxic mixture of sulfamic acid and urea in 1,4-dioxane medium was optimized, and the structure of sulfated ethanol lignin was studied. The process of lignin sulfation is described by a first-order equation in the temperature range 70–100 °C. The value of the rate constants is weakly dependent on the ratios of lignin and sulfating complex (sulfamic acid–urea mixture). The activation energy of the sulfation process decreases from 11.5 to 7.5 kJ/mol with an increase in the content of the sulfating complex (SC). The optimal conditions for sulfation of abies ethanol lignin with a high yield of water-soluble sulfated lignin [(100% of mass) with sulfur content of 7.9%] were found: temperature 95–100 °C, L/SC ratio 1:2.3–1:2.9, time 2 h. The composition and structure of water-soluble sulfated ethanol lignin were determined by elemental analysis, FTIR spectroscopy, two-dimensional NMR spectroscopy and gel permeation chromatography. It was shown that only alcoholic OH groups of ethanol lignin react with sulfamic acid. Sulfated ethanol lignin has a higher molecular weight and a lower degree of polydispersity compared to the initial ethanol lignin.

The IR spectra and molecular mass distribution of arabinogalactan sulfates in the form of sodium and ammonium salts, obtained using various sulfating reagents, were compared. According to the obtained data, the sulfated derivatives of arabinogalactan differ from each other by the nature of the hydrogen bonds and the molecular weight distribution. Using coagulological tests at the activation of coagulation of platelet-poor human plasma, in vitro study of the anticoagulant properties of arabinogalactan sulfated derivatives in various salt forms differing in methods of preparation, degree of sulfation and molecular weight was conducted. It was established that the sample in the form of arabinogalactan sodium salt (SAG 1) with a sulfur content of 13.2 wt.% аnd a polydispersity degree of 1.52 showed 2 times more anticoagulant activity than the sample in the form of ammonium salt of arabinogalactan (SAG 2) with the sulfur content of 6.6 wt.% and the degree of polydispersity of 1.30. Antithrombin (aIIa) activity of samples obtained by sulfation with pyridine and sulfuric anhydride complex (SAG 1) and sulfamic acid complex (SAG 2) was, respectively, 23.42±1.86 and 10.20±1.50 U/mg; the anti-factor Xa activity of SAG 1 and SAG 2 was 2.13±0.42 and 0.37±0.08 U/mg; and the ratio aIIa/aXa for SAG1 and SAG 2 was 11 and 28, respectively. The less activity of antifactor Xa(aXA) of SAG as compared to unfractionated heparin (UFG) and higher rations of activities aIIa/aXa may contribute the less provocation of bleeding by SAG samples in the comparition with UFG.

The organic xerogels, prepared from tannins and ethanol lignins of the fir (Abies sibirica), were synthesized for the first time. The influence of the composition of initial mixture and pH on the characteristics of xerogels obtained by sol-gel condensation of formaldehyde with polyphenols of fir has been studied. The possibility of regulating the density and porosity of gels by varying of the concentration of ethanol lignin in the initial mixture was established. It was found that tannin-lignin-formaldehyde gel with low-density (0.11 g/cm3), and very high porosity (92%) is formed at a mass ratio tannins and lignins equal to 1. According to FTIR data, the process of xerogel formation is carried out by cross-linking due to the formation of carbon-carbon and alkyl ethers bonds. SEM method confirmed the formation of branched macromolecular structure of gels from interconnected spherical particles of different sizes. Thermogravimetric analysis demonstrates greater thermal stability of tannin-formaldehyde gels compared with the tannin-lignin-formaldehyde gels. The increase of lignin concentration in gels more than 50–65% (by the mass) reduced the temperature of their intensive mass loss on 23–63 °С. The obtained organic gels are non-flammable polymers, and they can be used as thermal and fire retardant materials.

The effect of bifunctional catalyst Pt/ZrO₂ on the yield and composition of products of abies wood and ethanol lignin hydrogenation in supercritical ethanol at temperature of 250 °C was established. In the process of abies wood hydrogenation, the catalyst Pt/ZrO₂ increases the degree of conversion of wood from 52.0 to 65.7 wt.%, the yield of liquid products from 31.0 to 38.1 wt.%,.%, and also increases the content of monomeric compounds in the liquid products. In the presence of catalyst, the cellulose content in the solid product of wood catalytic hydrogenation reaches to 77.1 wt.%, and the content of lignin and hemicelluloses decreases to 21.2 wt.% and 1.7 wt.%, respectively. In the process of ethanol lignin hydrogenation the catalyst Pt/ZrO₂ increases the degree of lignin conversion from 86.0 to 99.4 wt.%, the yield of liquid products from 75.0 to 90.0 wt.%, and also reduces the yield of solid residue from 14.0 to 0.6 wt.% and the yield of gases from 4.7 to 3.3 wt.%. Thus, the polysaccharides of wood biomass complicate the reductive depolymerization of native lignin in comparison with the depolymerization of isolated ethanol lignin. The use of the catalyst Pt/ZrO₂ makes it possible to fractionate the abies wood in supercritical ethanol at 250 °C on solid product with a high content of cellulose, as well as liquid and gaseous products from lignin and hemicelluloses

The work describes a one-stage method of cellulose obtaining from fir wood based on peroxide delignification of wood under mild conditions (100 °C, atmospheric pressure) in the presence of acetic acid, water and catalyst of 2% wt. H2SO4. The possibility of obtaining cellulose with a residual lignin content

This article focuses on the aqueous complexation between two flavonoids (morin and morinsulfonate) and Pb2+ at constant ionic strength I=0.5 M (NaClO4). The determination of stability constants of ML complexes were performed at wide pH range. Two obtained constants are 14.8 ± 0.1 and 15.2 ± 0.1 logarithmic units for morin and morin-5’-sulfonic acid, respectively. For estimating the thermodynamic stability of the complexes studied, the Def2-SV(P)/DFT/PBE0/SMD method has been used. Different computational models were tested to describe the data obtained. The theoretical values of logK reproduce the experimental parameters within reasonable errors.

The analysis of the literature on the spectral methods of lignins study was carried out. The most suitable spectral methods for elucidating the structural features of soluble organosolv lignins were selected. The possibilities of FTIR, 1Н NMR, 13С NMR and 2D HSQC NMR methods were demonstrated on the example of studying the structure of ethanollignins obtained from fir and aspen wood. It was established that fir and aspen lignins are G type and GS type lignins, respectively. The HSQC spectra analysis demonstrated a presence of β–O–4′, β–β′, β–5′ linkages in the ethanollignins. It was found that β–O–4′ linkages in ethanollignins from fir and aspen were partially acylated with ethoxy groups in the α-position

The toxic and corrosive mineral acids are used traditionally in the processes of plant polysaccharides hydrolysis. The use of solid acid catalysts improves the environmental safety of hydrolysis processes and simplifies the separation of the catalyst from the reaction products. The stability of solid acid catalysts based on mesoporous SBA-15 and graphite-like carbon material Sibunit-4, containing SO3Hgroups, in the process of larch arabinogalactan hydrolysis at 150 °С was studied. The compositions of the resulting hydrolysates were investigated by gas chromatography. It was established that acidmodified Sibunit-4 does not lose the catalytic activity after three cycles of hydrolysis process for a total duration of 12 hours. Modified SBA-15 catalyst was less stable at the studied conditions. The decrease of monosaccharides concentration in the hydrolysates, the changes in the structure of the catalyst and 40% loss of its weight were found after the third cycle of larch arabinogalactan hydrolysis

The acid–base properties, protonation activity, and complexing abilities of two substituted β-diketones have been studied. The equilibrium constants of dissociation (pKa) were obtained at constant ...

The effect of a bifunctional catalyst containing nano-dispersed ruthenium particles on an oxidized carbon support “Sibunit” on the yield and composition of products in the processes of hydrogenation of abies wood and abies ethanol-lignin in a supercritical ethanol medium at 250° C was studied. The presence of Ru/C catalyst resulted in a raise the ethanol-lignin conversion from 85 to 98 wt.%, the yield of liquid product from 75 to 85 wt.%, the yield of gases – by 1.5 times, but the yield of solid products dropped from 14 to 2.8 wt.%. Ruthenium catalyst increased the conversion of abies wood by 12.5 wt.%, but did not affect the yield of liquid products. The yield of the solid residue in the presence of the catalyst was reduced by 12.5 wt.%, and the yield of gases rose by 2.5 times. Simultaneously, the ruthenium catalyst promoted the process of hydrodeoxygenation of liquid products, diminution their average molecular mass from 1174 g/mol to 827 g/mol and the formation of monomeric and dimeric compounds with a molecular mass 193 and 426 g/mol, respectively. The solid residue of catalytic hydrogenation contained 70.1 wt.% of cellulose. Thus, the application of Ru/C catalyst in the process of hydrogenation of abies wood allowed the reductive fractionation of wood biomass into a solid cellulose product, liquid and gaseous products from lignin and hemicelluloses.

Acid–base activity, keto-enol tautomerism and complexing properties of 6-bromoquercetin are investigated in water media under different conditions. The constants of dissociation (pKa) have been determined in pH region at various ionic strengths. The analysis of the protonation process is conducted in strongly acidic solutions of HCl. The complexation was studied with trivalent lanthanides. The formation constants of monocomplex species ML (M(III)=Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, Lu) have been obtained. DFT calculations were carried out for interpretation and verification of received results.

Sulfation of larch wood arabinogalactan (AG) with sulfamic acid in dimethylsulfoxide (DMSO) medium in the presence of urea was studied for the first time. The use of DMSO as a solvent instead of more toxic 1,4-dioxane allows to sulfate AG under homogeneous conditions. The sulfated AG with a high sulfur content (12.0-12.5 wt %) was produced by sulfation at a temperature of 85-90 °C, the molar ratio of AG / sulfating agent equal to 1:0.85 during 2-3 h. The introduction of sulfate groups into the structure of arabinogalactan was confirmed by the appearance of new absorption bands in FTIR and FT Raman spectra, characteristic for the vibrations of the sulfate groups. It was proved by 13C NMR spectroscopy that the predominant substitution of the primary hydroxyl groups at C6 carbon atoms of the terminal galactose units of main and side chains of arabinogalactan takes place. Simultaneously, the hydroxyl groups associated with C2 and C4 carbon atoms of galactose unit of the main chain are only partially sulfated. According to results of GPC study, the sulfated AG is characterized by a narrow molecular weight distribution with an average molecular weight of 18.8 kDa and a polydispersity of 1.3. Supplementary information The online version contains supplementary material available at 10.1007/s00226-021-01341-2.

fff; International audience; Catalytic hydrogenolysis in the medium of supercritical organic solvents is a promising way of wood lignins depolymerization into liquid products.In this study, for the first time, the catalytic properties of bifunctional catalysts Ru/C, Pt/ZrO2, NiCuMo/SiO2, containing nanosized metal particles on acidic groups are compared in the processes of aspen wood and ethanol lignin hydrogenolysis in supercritical ethanol.The most active catalysts are Ru/C and Pt/ZrO2 which provide the high conversion of wood (to 78.0 wt%), significant yield of liquid products (to 50.6 wt%) and low yield of solid rest (to 22.0 wt%) at temperature 250 °C and H2 pressure 9.0 MPa. These catalysts increase the yield of monomeric compounds in liquid products from 10.5 % to 50.4 % on mass of lignin.GC–MS analysis shows that alkyl derivatives of methoxyphenols (mainly propyl syringol and propyl guaiacol) are dominated in liquid products. Solid products of aspen wood catalytic hydrogenolysis contain mainly cellulose (to 82.2 wt%). Therefore, the catalytic hydrogenolysis in supercritical ethanol in the presence of by functional catalysts Ru/C and Pt/ZrO2 allows to fractionate the aspen wood biomass on cellulose and liquid products enriched with propyl syringol and propyl guaiacol.In catalytic hydrogenolysis of ethanol lignin the yield of alkyl derivatives of methoxyphenols is lower compared to wood. This is probably due to the reduced content of reactive β-O-4 bonds in the structure of ethanol lignin compared to native lignin of aspen wood. As follows from the results obtained, native lignin of wood is easier depolymerized to monomeric compounds in the process of catalytic hydrogenolysis than ethanol lignin, isolated from wood.According to GPC data, the catalysts shift to the region of lower molecular mass the molecular mass distribution of liquid products of aspen wood and ethanol lignin hydrogenolysis.

Supported gold and platinum particles on titanium oxide catalysts were evaluated in the oxidative depolymerization of lignins toward high added value aromatics under mild conditions (T: 150 °C, Pair: 20 bar, CNaOH: 10 g/L, 1 h). Kraft and ethanol Organosolv lignins were engaged in the study. Gold catalyst showed a strong tendency to further oxidize aromatics produced from lignin depolymerization to volatile compounds leading to very low yield in target molecules. On the contrary, platinum-based catalysts were allowed to observe enhanced yields that were attributed to its ability to preserve lignin’s substructure during the reaction. A kinetic model was constructed based on the results observed, which allowed us to identify the occurrence of condensation reactions during lignin oxidation and degradation of the produced aromatic compounds as the main limitations to reach high product yields. Insights on lignin oxidation and the catalyst’s role lead through this study would help to reach higher control over lignin valorization.

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.

SSCI-VIDE+CDFA+LDJ; International audience; Several lignin samples of varying botanical nature (softwood, hardwood, or annual plants) and extraction procedures (Kraft, Organosolv, or soda) were fully characterized by complementary techniques and engaged in “catalyst-free” depolymerization in air under basic conditions. Treatment of the complex reaction mixture was optimized to ensure reproducibility, careful analyses, and accurate data. After an optimization of the reaction conditions, we were able to recover high amounts of aromatic compounds (up to 19%wt). Additionally, we demonstrated a relation between lignin’s structure, i.e., the accessible phenol moieties and inter-unit linkages, and the yields of aromatic compounds, thus showing the importance of the extraction process to optimize lignin’s potential. This work provides valuable reference for developing further lignin depolymerization under basic media.

A new method for preparation of organic aerogels by sol–gel polymerization of formaldehyde with polyphenols (PPs), isolated from larch bark and birch bark, was developed. The functional composition and properties of the original polyphenols were studied by thermogravimetric methods and FTIR spectroscopy. It was found that larch polyphenol material had higher thermal stability in the temperature range 25−700°C, while the process of thermal decomposition of birch bark polyphenols completes at 600°C. It has been established that polyphenol larch compounds contain more aromatic structures and hydroxyl groups. The effect of the pH of gelation solutions in the range from 4 to 12 on the porous structure of organic gels synthesized from polyphenols was studied. The porous structures and adsorption properties of polyphenol-formaldehyde organic gels were studied using the BET method, scanning electron microscopy and sorption (methylene blue and gelatin). It was shown that an increase in pH contributes to the formation of a product with a more compacted texture. The electron microscopic images of polymer gels demonstrate a uniform granular texture with visible microglobules with an average particle size of ≈50−70 nm.

For the first time, the synthesis of water-soluble copper-containing microcrystalline cellulose sulfates (Сu-MCS) has been performed by the ion exchange method. The composition of the products has been studied by chemical methods and X-ray spectral microanalysis. The copper content in the Сu-MCS samples was 12.6–14.1%. The absence of sodium in the resulting polymer indicates the complete substitution of the sodium cations by the copper cations in the sodium salt of MCC sulfate. The structure of the copper-containing sulfates of microcrystalline cellulose has been confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and electron paramagnetic resonance (EPR). According to the XRD method, Сu-MCS and Na-MCS have an amorphous structure in contrast to the original MCC samples, which have a high degree of crystallinity. The EPR data have demonstrated the formation of a pseudocrystalline structure of the copper-containing salt system in the Сu-MCS samples. As shown by atomic-force microscopy, the surface of the Сu-MCS films consists of homogeneous crystallites, which have a spherical or slightly extended form with the size of about 70 nm. The film surface is quite homogeneous in its phase composition and contains no impurities.

The effect of the conditions of the acetylation process of raw and activated birch bark on the yield and composition of the products is investigated. The structure of biologically active betulin diacetate (BDA) is confirmed with physicochemical methods. The optimal regimes of the one-step original method for the production of BDA from raw and activated birch bark are established using the experimental and computational techniques.

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.