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L. Djakovitch - One of the best experts on this subject based on the ideXlab platform.
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Catalytic hydrogenolysis of native and organosolv lignins of Aspen Wood to liquid products in supercritical ethanol medium
Catalysis Today, 2020Co-Authors: B. N. Kuznetsov, V. I. Sharypov, S. V. Baryshnikov, A. V. Miroshnikova, Oxana P. Taran, Vadim A. Yakovlev, A. V. Lavrenov, L. DjakovitchAbstract:Abstract 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.
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Thermal conversion of mechanically activated mixtures of Aspen Wood-zeolite catalysts in a supercritical ethanol
Journal of Analytical and Applied Pyrolysis, 2018Co-Authors: B. N. Kuznetsov, S. V. Baryshnikov, A. V. Pestunov, Victor I. Sharypov, Natalia G. Beregovtsova, А.v. Vosmerikov, L. DjakovitchAbstract:Abstract The mechanical activation of the mixture of Aspen Wood – high silica zeolite catalysts increases the Wood thermal conversion in supercritical ethanol and rises the yield of liquid products. TH-HSZ-30 with Si/Al = . Zeolite catalysts allow to fractionate the mechanically activated Wood in supercritical ethanol at 270 °C on solid lignocellulose and on soluble products from hemicelluloses, presented by furfural, 5-hydroxymethylfurfural, levulinic acid and ethyl esters. The elevated temperature (350 °C) decreases the yield of liquid products due to the intensification of secondary reactions of their transformation to gases and chars. The possible mechanism of Wood catalytic conversion to bio-liquids in supercritical ethanol is discussed.
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Kinetic study of Aspen-Wood sawdust delignification by H_2O_2 with sulfuric acid catalyst under mild conditions
Reaction Kinetics Mechanisms and Catalysis, 2013Co-Authors: B. N. Kuznetsov, I. G. Sudakova, N. V. Garyntseva, L. Djakovitch, C. PinelAbstract:The process of Aspen-Wood delignification in the medium “hydrogen peroxide–acetic acid–water–sulfuric acid catalysts” at mild conditions (temperature 70–100 °C, atmospheric pressure) is described by the first order equation. Rate constants vary from 0.25 × 10^−4 (70 °C) to 2.5 × 10^−4 s^−1 (100 °C). The activation energy of Aspen-Wood delignification is near 91 kJ mol^−1. The rather high value of activation energy points to the insignificant role of diffusion limitations at used conditions of Aspen-Wood delignification. The optimal process conditions for obtaining of the pure cellulose (residual lignin content less 1 wt%) with a yield near 45 wt% were selected. Obtained cellulose has the structure similar to the commercial microcrystalline cellulose.
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Kinetic study of Aspen-Wood sawdust delignification by H2O2 with sulfuric acid catalyst under mild conditions
Reaction Kinetics Mechanisms and Catalysis, 2013Co-Authors: B. N. Kuznetsov, I. G. Sudakova, N. V. Garyntseva, L. Djakovitch, C. PinelAbstract:The process of Aspen-Wood delignification in the medium “hydrogen peroxide–acetic acid–water–sulfuric acid catalysts” at mild conditions (temperature 70–100 °C, atmospheric pressure) is described by the first order equation. Rate constants vary from 0.25 × 10−4 (70 °C) to 2.5 × 10−4 s−1 (100 °C). The activation energy of Aspen-Wood delignification is near 91 kJ mol−1. The rather high value of activation energy points to the insignificant role of diffusion limitations at used conditions of Aspen-Wood delignification. The optimal process conditions for obtaining of the pure cellulose (residual lignin content less 1 wt%) with a yield near 45 wt% were selected. Obtained cellulose has the structure similar to the commercial microcrystalline cellulose.
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Kinetic study of Aspen-Wood sawdust delignification by H2O2 with sulfuric acid catalyst under mild conditions
Reaction kinetics mechanisms and catalysis, 2013Co-Authors: B. N. Kuznetsov, I. G. Sudakova, N. V. Garyntseva, L. Djakovitch, C. PinelAbstract:The process of Aspen-Wood delignification in the medium "hydrogen peroxide-acetic acid-water-sulfuric acid catalysts" at mild conditions (temperature 70-100 A degrees C, atmospheric pressure) is described by the first order equation. Rate constants vary from 0.25 x 10(-4) (70 A degrees C) to 2.5 x 10(-4) s(-1) (100 A degrees C). The activation energy of Aspen-Wood delignification is near 91 kJ mol(-1). The rather high value of activation energy points to the insignificant role of diffusion limitations at used conditions of Aspen-Wood delignification. The optimal process conditions for obtaining of the pure cellulose (residual lignin content less 1 wt%) with a yield near 45 wt% were selected. Obtained cellulose has the structure similar to the commercial microcrystalline cellulose.
Göran Gellerstedt - One of the best experts on this subject based on the ideXlab platform.
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improved lignin properties and reactivity by modifications in the autohydrolysis process of Aspen Wood
Industrial Crops and Products, 2008Co-Authors: Göran GellerstedtAbstract:Abstract Autohydrolysis of Aspen Wood breaks down lignin β-O-4 linkages via both acidolysis and homolytical cleavage. A simultaneous repolymerization by lignin–lignin condensation is the major reason for the low degree of delignification and the poor lignin reactivity. Modification of the autohydrolysis reaction by the addition of either NaOH or 2-naphthol changes the mechanism such that less acidolysis and fewer lignin–lignin condensation reactions take place, and an almost complete delignification can be achieved. The resulting isolated lignins have a low M w , a light color and still contain some of the native β-O-4 linkages. Lignin from autohydrolysis in the presence of NaOH possesses more carboxylic acid groups, while the addition of 2-naphthol results in a lignin with a large amount of phenolic hydroxyl groups and incorporated naphthalene rings. These types of change are beneficial since the lignin structure becomes much more homogeneous with a greater potential for further upgrading and use.
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lignin depolymerization repolymerization and its critical role for delignification of Aspen Wood by steam explosion
Bioresource Technology, 2007Co-Authors: Jiebing Li, Gunnar Henriksson, Göran GellerstedtAbstract:Steam explosion is an important process for the fractionation of biomass components. In order to understand the behaviour of lignin under the conditions encountered in the steam explosion process, as well as in other types of steam treatment, Aspen Wood and isolated lignin from Aspen were subjected to steam treatment under various conditions. The lignin portion was analyzed using NMR and size exclusion chromatography as major analytical techniques. Thereby, the competition between lignin depolymerization and repolymerization was revealed and the conditions required for these two types of reaction identified. Addition of a reactive phenol, 2-naphthol, was shown to inhibit the repolymerization reaction strongly, resulting in a highly improved delignification by subsequent solvent extraction and an extracted lignin of uniform structure.
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Lignin depolymerization/repolymerization and its critical role for delignification of Aspen Wood by steam explosion.
Bioresource technology, 2006Co-Authors: Gunnar Henriksson, Göran GellerstedtAbstract:Steam explosion is an important process for the fractionation of biomass components. In order to understand the behaviour of lignin under the conditions encountered in the steam explosion process, as well as in other types of steam treatment, Aspen Wood and isolated lignin from Aspen were subjected to steam treatment under various conditions. The lignin portion was analyzed using NMR and size exclusion chromatography as major analytical techniques. Thereby, the competition between lignin depolymerization and repolymerization was revealed and the conditions required for these two types of reaction identified. Addition of a reactive phenol, 2-naphthol, was shown to inhibit the repolymerization reaction strongly, resulting in a highly improved delignification by subsequent solvent extraction and an extracted lignin of uniform structure.
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Carbohydrate reactions during high-temperature steam treatment of Aspen Wood
Applied Biochemistry and Biotechnology, 2005Co-Authors: Gunnar Henriksson, Göran GellerstedtAbstract:Aspen Wood was treated with steam at different time-temperature severity factors. Analysis of the amounts of acids released revealed a relationship between the acidity and the formation of furfural and hydroxymethyl furfural as degradation products from carbohydrates. It is suggested that two concurrent or consecutive mechanisms are responsible for the observed results: a homolytic cleavage and an acid hydrolysis of glucosidic linkages in the polysaccharides. By preimpregnating the Wood with alkali, hydrolysis can be eliminated, resulting in a much cleaner depolymerization of the polysaccharides without any further acid-catalyzed degradation. The enzymatic digestibility of the steam-treated Wood material for the formation of glucose was compared with that of steam-exploded Wood. A more efficient route for glucose production from steam-exploded Wood was found as long as the biomass-pretreated material was homogeneous and without shives.
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improved lignin properties and reactivity by modifications in the autohydrolysis process of Aspen Wood
7th International Lignin Institute (ILI) Forum, 2005Co-Authors: Göran GellerstedtAbstract:Improved lignin properties and reactivity by modifications in the autohydrolysis process of Aspen Wood
B. N. Kuznetsov - One of the best experts on this subject based on the ideXlab platform.
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Catalytic hydrogenolysis of native and organosolv lignins of Aspen Wood to liquid products in supercritical ethanol medium
Catalysis Today, 2020Co-Authors: B. N. Kuznetsov, V. I. Sharypov, S. V. Baryshnikov, A. V. Miroshnikova, Oxana P. Taran, Vadim A. Yakovlev, A. V. Lavrenov, L. DjakovitchAbstract:Abstract 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.
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Kinetic Study and Optimization of Catalytic Peroxide Delignification of Aspen Wood
Kinetics and Catalysis, 2018Co-Authors: B. N. Kuznetsov, I. G. Sudakova, N. V. Garyntseva, Nikolai V. Chesnokov, A. V. Pestunov, L. D’yakovich, K. PinelAbstract: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.
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Thermal conversion of mechanically activated mixtures of Aspen Wood-zeolite catalysts in a supercritical ethanol
Journal of Analytical and Applied Pyrolysis, 2018Co-Authors: B. N. Kuznetsov, S. V. Baryshnikov, A. V. Pestunov, Victor I. Sharypov, Natalia G. Beregovtsova, А.v. Vosmerikov, L. DjakovitchAbstract:Abstract The mechanical activation of the mixture of Aspen Wood – high silica zeolite catalysts increases the Wood thermal conversion in supercritical ethanol and rises the yield of liquid products. TH-HSZ-30 with Si/Al = . Zeolite catalysts allow to fractionate the mechanically activated Wood in supercritical ethanol at 270 °C on solid lignocellulose and on soluble products from hemicelluloses, presented by furfural, 5-hydroxymethylfurfural, levulinic acid and ethyl esters. The elevated temperature (350 °C) decreases the yield of liquid products due to the intensification of secondary reactions of their transformation to gases and chars. The possible mechanism of Wood catalytic conversion to bio-liquids in supercritical ethanol is discussed.
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Integration of peroxide delignification and sulfamic acid sulfation methods for obtaining cellulose sulfates from Aspen Wood
European Journal of Wood and Wood Products, 2017Co-Authors: B. N. Kuznetsov, I. G. Sudakova, N. V. Garyntseva, Svetlana A. Kuznetsova, Vladimir A. Levdansky, Alexander V. LevdanskyAbstract: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.
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Kinetic study of Aspen-Wood sawdust delignification by H_2O_2 with sulfuric acid catalyst under mild conditions
Reaction Kinetics Mechanisms and Catalysis, 2013Co-Authors: B. N. Kuznetsov, I. G. Sudakova, N. V. Garyntseva, L. Djakovitch, C. PinelAbstract:The process of Aspen-Wood delignification in the medium “hydrogen peroxide–acetic acid–water–sulfuric acid catalysts” at mild conditions (temperature 70–100 °C, atmospheric pressure) is described by the first order equation. Rate constants vary from 0.25 × 10^−4 (70 °C) to 2.5 × 10^−4 s^−1 (100 °C). The activation energy of Aspen-Wood delignification is near 91 kJ mol^−1. The rather high value of activation energy points to the insignificant role of diffusion limitations at used conditions of Aspen-Wood delignification. The optimal process conditions for obtaining of the pure cellulose (residual lignin content less 1 wt%) with a yield near 45 wt% were selected. Obtained cellulose has the structure similar to the commercial microcrystalline cellulose.
Кузнецов Б.Н. - One of the best experts on this subject based on the ideXlab platform.
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Influence of Preliminary Mechanical Treatments on Acidic Hydrolysis of Aspen Wood
Сибирский федеральный университет. Siberian Federal University., 2020Co-Authors: Барышников С.В., Шарыпов В.И., Кузнецов Б.Н., Жижаев А.М., Алашкевич Ю.Д., Baryshnikov Sergei, Sharypov Victor, Kuznetsov, Boris N., Zhyzhaev, Anatoly M., Alashkevich, Yuriy D.Abstract:For the mechanical activation of Aspen Wood in aqueous medium the cuttery, jet, vibratory rod mills and mechanochemical activator were used. The influence of treatment conditions on Wood structure and on activated Wood acidic hydrolysis was studied.It was found that the preliminary mechanical activation on Aspen Wood increases the yield of easy - hydrolyzed polysaccharides and the rate of their hydrolysis to sugars with 2 % HCl. The higher influence on the reaction ability in hydrolysis process was observed after Aspen Wood treatment in a planetary activator mill AGO - 2.Изучено влияние механической обработки древесины осины в аппаратах ножевого и струйного, вибрационного помолов и механохимического активирования в водной среде на ее строение и реакционную способность в процессе кислотного гидролиза.Показано, что используемые способы воздействия на древесину приводят к увеличению выхода легкогидролизуемых веществ и скорости их гидролиза в 2 % HCl. Наибольшее влияние оказывает механохимическая обработка древесины в мельнице-активаторе центробежно - планетарного типа АГО - 2
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The Integration of Catalytic Processes of Acid Hydrolysis and Peroxide Delignification to Obtain the Bioethanol from Aspen Wood
Сибирский федеральный университет. Siberian Federal University, 2020Co-Authors: Кузнецов Б.Н., Kuznetsov, Boris N., Яценкова О.В., Скрипников А.М., Береговцова Н.Г., Козлова С.А., Иванченко Н.М., Yatsenkova Olga, Skripnikov, Andrei M., Beregovtsova, Natalia G.Abstract:Изучены процессы каталитического гидролиза гемицеллюлоз и целлюлозы древесины осины при температурах 100 и 150 °C. В качестве катализаторов гидролиза использовали растворенные минеральные кислоты (H2SO4, HCl), ионообменную смолу Amberlyst–15 и кислотно-модифицированные SBA–15, Сибунит–4. Определены оптимальные условия осуществления каталитических процессов кислотного гидролиза гемицеллюлоз древесины, пероксидной делигнификации лигноцеллюлозы и гидролиза целлюлозы для получения гидролизатов с максимальным содержанием глюкозы и минимальным количеством ингибиторов ферментативных процессов – фурфурола и 5–гидроксиметилфурфурола. Рассчитан предполагаемый выход биоэтанола, получаемого при интеграции оптимизированных каталитических процессов кислотного гидролиза полисахаридов и пероксидной делигнификации лигноцеллюлозы древесины осиныThe processes of catalytic hydrolysis of hemicelluloses and cellulose of Aspen Wood were studied at the temperatures 100 and 150 °C. The dissolved mineral acids (H2SO4, HCl), ion exchange resin Amberlyst-15 and acid-modified SBA-15, Sibunit-4 were used in hydrolysis of Aspen Wood as the catalysts. The optimal conditions for the implementation of catalytic processes of acid hydrolysis of Wood hemicelluloses, peroxide delignification of lignocellulose and hydrolysis of cellulose for the production of hydrolysates with the maximum glucose yield and the minimum amount of inhibitors of enzymatic processes (furfural and 5-hydroxymethylfurfural) were established. The estimated yields of bioethanol obtained by integration of optimized catalytic processes of acid hydrolysis of polysaccharides and peroxide delignification of lignocellulose of Aspen Wood were evaluate
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The Study of Thermal Conversion of Mechanically Activated Aspen Wood in the Presence of High-Silica Zeolite Catalyst
Сибирский федеральный университет. Siberian Federal University., 2020Co-Authors: Шарыпов В.И., Барышников С.В., Кузнецов Б.Н., Жижаев А.М., Sharypov Victor, Береговцова Н.Г., Beregovtsova, Natalia G., Восмериков А.В., Baryshniko Sergei, Zhyzhaev, Anatoly M.Abstract:Исследовано влияние добавок высококремнеземного цеолита в Н-форме с силикатным модулем 60 (НВКЦ-60) и механохимической обработки древесины осины в мельнице-активаторе АГО-2 на ее термические превращения. Установлено, что совместное механохимическое активирование древесины осины и катализатора НВКЦ-60 приводит к резкому уменьшению размера частиц компонентов смеси, разрушению основных структурных компонентов древесины, дисперсному распределению катализатора по поверхности древесины и к увеличению степени конверсии древесины осины в процессе термопревращения в среде сверхкритического этанола. В присутствии катализатора НВКЦ-60 происходит увеличение выхода этанолрастворимых продуктов, выкипающих до 180 °С, в 1,6–2,2 раза и промотирование реакции этерификации кислот, образующихся при деструкции компонентов древесиныThe influence of zeolite catalysts in the H-form with silicate module 60 (HSZ-60) and mechanochemical treatment in the activator mill AGO-2 on the thermal conversion of Aspen Wood has been studied. It was found that the joint mechanochemical activation of Aspen Wood and HSZ-60 catalyst results in a drastic decrease in particles size of the mixture components in destruction of the main structural components of Wood and increases the homogenity of zeolite catalyst distribution on the Wood surface and the degree of Aspen Wood conversion in supercritical ethanol. Catalyst HSZ-60 increases by 1,6 – 2,2 times the yield of ethanol soluble products with boiling point up to 180 °С and promotes the etherification reactions of acids, obtained during degradation of Wood component
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Thermal Conversion of Aspen Wood Lignin in Ethanol in the Presence of Zeolite Catalysts
Сибирский федеральный университет. Siberian Federal University., 2020Co-Authors: Шарыпов В.И., Барышников С.В., Кузнецов Б.Н., Sharypov Victor, Береговцова Н.Г., Beregovtsova, Natalia G., Восмериков А.В., Таран О.П., Агабеков В.Е., Baryshnikov SergeiAbstract:The influence of acid zeolite catalysts with different silicate modulus on the thermal conversion of Aspen Wood lignin and on the composition of obtained products was studied. It was found that at the process temperature 350 °C the degree of lignin conversion to liquid and gaseous products was increased by 20-30 % under the action of zeolite catalysts. The maximum conversion of lignin (71 wt. %) and the high yield of light fraction (
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Study of the Carbonization of Birch and Aspen Wood Modified by Explosive Autohydrolysis and ZnCl2 Additives
Сибирский федеральный университет. Siberian Federal University., 2020Co-Authors: Цыганова С.И., Кузнецов Б.Н., Чесноков Н.В., Tsyganova Svetlana, Chesnokov Nikolai, Kuznetsov, Boris N.Abstract:Изучено влияние модификации древесины березы и осины взрывным автогидролизом и добавкой хлорида цинка на выход, состав и пористую структуру углеродных продуктов, образующихся в процессе карбонизации модифицированной древесины. Обнаружено, что древесина осины подвергается более глубоким превращениям в процессах автогидролиза и карбонизации, чем древесина березы. При карбонизации автогидролизованной древесины с добавкой ZnCl2 наблюдается повышение выхода углеродного продукта до 40 %, а его удельной поверхности – примерно на два порядка вне зависимости от природы древесины. Показано, что процессы интенсивного терморазложения модифицированной древесины протекают при более низких температурах, чем исходной древесиныThe influence of birch and Aspen Wood modification by explosive autohydrolysis and ZnCl2 additive on the yield, composition and porous structure of carbon products obtained for carbonization of modified Wood has been studied. It was shown that the Aspen Wood is subjected to a more profound transformation in the processes of explosive autohydrolysis and carbonation than the birch Wood. The yield of the carbon product increases up to 40 %, and the specific surface area rises by two orders for carbonation of autohydrolyzed Wood modified by ZnCl2 regardless on the nature of Wood. It was shown that the processes of intensive thermal decomposition of the modified Wood are carried out at lower temperatures, as compared to the initial woo
S. V. Baryshnikov - One of the best experts on this subject based on the ideXlab platform.
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Catalytic hydrogenolysis of native and organosolv lignins of Aspen Wood to liquid products in supercritical ethanol medium
Catalysis Today, 2020Co-Authors: B. N. Kuznetsov, V. I. Sharypov, S. V. Baryshnikov, A. V. Miroshnikova, Oxana P. Taran, Vadim A. Yakovlev, A. V. Lavrenov, L. DjakovitchAbstract:Abstract 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.
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Thermal conversion of mechanically activated mixtures of Aspen Wood-zeolite catalysts in a supercritical ethanol
Journal of Analytical and Applied Pyrolysis, 2018Co-Authors: B. N. Kuznetsov, S. V. Baryshnikov, A. V. Pestunov, Victor I. Sharypov, Natalia G. Beregovtsova, А.v. Vosmerikov, L. DjakovitchAbstract:Abstract The mechanical activation of the mixture of Aspen Wood – high silica zeolite catalysts increases the Wood thermal conversion in supercritical ethanol and rises the yield of liquid products. TH-HSZ-30 with Si/Al = . Zeolite catalysts allow to fractionate the mechanically activated Wood in supercritical ethanol at 270 °C on solid lignocellulose and on soluble products from hemicelluloses, presented by furfural, 5-hydroxymethylfurfural, levulinic acid and ethyl esters. The elevated temperature (350 °C) decreases the yield of liquid products due to the intensification of secondary reactions of their transformation to gases and chars. The possible mechanism of Wood catalytic conversion to bio-liquids in supercritical ethanol is discussed.
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Effect of Different Activation Methods on the Composition, Structure and Reactivity of Aspen Wood
2012Co-Authors: B. N. Kuznetsov, V. I. Sharypov, Svetlana A. Kuznetsova, S. V. Baryshnikov, V. G. Danilov, Olga V. Yatsenkova, N. M. IvanchenkoAbstract:An effect of different methods for Aspen Wood activation (grinding in the mills of different types, explosive autohydrolysis, catalytic oxidation by hydrogen peroxide and the combination of these methods) exerted on the structure, chemical composition and reactivity of activated Wood was studied. It has been found that all the methods of Aspen Wood mechanical pretreatment result in changing the supramolecular structure, chemical composition and reactivity thereof: activated samples exhibit increasing the content of readily hydrolysable polysaccharides, with reducing the concentration of polysaccharides difficult to hydrolyze and of residual lignin, as well as with increasing the rate of polysaccharide acidic hydrolysis into monosaccharides and the rate of lignin oxidation by hydrogen peroxide.
