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N. Essayem - One of the best experts on this subject based on the ideXlab platform.
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direct Solid lewis acid catalyzed wood liquefaction into lactic acid kinetic evidences that wood pretreatment might not be a prerequisite
Chemcatchem, 2017Co-Authors: Y. Swesi, C. Nguyen, F. Rataboul, M. Eternot, P. Fongarland, N. EssayemAbstract:The objective of the present work was to determine if wood sawdust can be used instead of isolated cellulose in the general Solid-acid-catalyzed production of chemicals. The kinetics of model cellulose and pine-wood sawdust liquefaction into lactic acid were determined in the presence of a Solid Lewis acid, ZrW. The catalytic hydrolysis of pine wood was performed at 190 °C in a large-scale batch reactor (2.5 L). Similar kinetic curves of lactic formation were obtained for cellulose and wood as substrates. Moreover, the initial lactic acid production rate of pine-wood sawdust was higher than that of model cellulose, proving that, in spite of the presence of lignin/hemicellulose, the Catalyst drives the transformation towards lactic acid formation. However, our results give also evidence of Solid-Catalyst deactivation for both cellulose and wood substrates. This result indicates that if wood pretreatment can be bypassed, the bottleneck will be the Solid-Catalyst regeneration and recycling.
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Direct Solid Lewis Acid Catalyzed Wood Liquefaction into Lactic Acid: Kinetic Evidences that Wood Pretreatment Might Not be a Prerequisite
ChemCatChem, 2017Co-Authors: Y. Swesi, C. Nguyen, F. Rataboul, M. Eternot, P. Fongarland, N. EssayemAbstract:The objective of the present work was to determine if wood sawdust can be used instead of isolated cellulose in the general Solid-acid-catalyzed production of chemicals. The kinetics of model cellulose and pine-wood sawdust liquefaction into lactic acid were determined in the presence of a Solid Lewis acid, ZrW. The catalytic hydrolysis of pine wood was performed at 190 degrees C in a large-scale batch reactor (2.5 L). Similar kinetic curves of lactic formation were obtained for cellulose and wood as substrates. Moreover, the initial lactic acid production rate of pine-wood sawdust was higher than that of model cellulose, proving that, in spite of the presence of lignin/hemicellulose, the Catalyst drives the transformation towards lactic acid formation. However, our results give also evidence of Solid-Catalyst deactivation for both cellulose and wood substrates. This result indicates that if wood pretreatment can be bypassed, the bottleneck will be the Solid-Catalyst regeneration and recycling.
Y. Swesi - One of the best experts on this subject based on the ideXlab platform.
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direct Solid lewis acid catalyzed wood liquefaction into lactic acid kinetic evidences that wood pretreatment might not be a prerequisite
Chemcatchem, 2017Co-Authors: Y. Swesi, C. Nguyen, F. Rataboul, M. Eternot, P. Fongarland, N. EssayemAbstract:The objective of the present work was to determine if wood sawdust can be used instead of isolated cellulose in the general Solid-acid-catalyzed production of chemicals. The kinetics of model cellulose and pine-wood sawdust liquefaction into lactic acid were determined in the presence of a Solid Lewis acid, ZrW. The catalytic hydrolysis of pine wood was performed at 190 °C in a large-scale batch reactor (2.5 L). Similar kinetic curves of lactic formation were obtained for cellulose and wood as substrates. Moreover, the initial lactic acid production rate of pine-wood sawdust was higher than that of model cellulose, proving that, in spite of the presence of lignin/hemicellulose, the Catalyst drives the transformation towards lactic acid formation. However, our results give also evidence of Solid-Catalyst deactivation for both cellulose and wood substrates. This result indicates that if wood pretreatment can be bypassed, the bottleneck will be the Solid-Catalyst regeneration and recycling.
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Direct Solid Lewis Acid Catalyzed Wood Liquefaction into Lactic Acid: Kinetic Evidences that Wood Pretreatment Might Not be a Prerequisite
ChemCatChem, 2017Co-Authors: Y. Swesi, C. Nguyen, F. Rataboul, M. Eternot, P. Fongarland, N. EssayemAbstract:The objective of the present work was to determine if wood sawdust can be used instead of isolated cellulose in the general Solid-acid-catalyzed production of chemicals. The kinetics of model cellulose and pine-wood sawdust liquefaction into lactic acid were determined in the presence of a Solid Lewis acid, ZrW. The catalytic hydrolysis of pine wood was performed at 190 degrees C in a large-scale batch reactor (2.5 L). Similar kinetic curves of lactic formation were obtained for cellulose and wood as substrates. Moreover, the initial lactic acid production rate of pine-wood sawdust was higher than that of model cellulose, proving that, in spite of the presence of lignin/hemicellulose, the Catalyst drives the transformation towards lactic acid formation. However, our results give also evidence of Solid-Catalyst deactivation for both cellulose and wood substrates. This result indicates that if wood pretreatment can be bypassed, the bottleneck will be the Solid-Catalyst regeneration and recycling.
Avelino Corma - One of the best experts on this subject based on the ideXlab platform.
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Organic-inorganic supramolecular Solid Catalyst boosts organic reactions in water.
Nature communications, 2016Co-Authors: Pilar García-garcía, José María Moreno, Urbano Díaz, Marta Bruix, Avelino CormaAbstract:Coordination polymers and metal-organic frameworks are appealing as synthetic hosts for mediating chemical reactions. Here we report the preparation of a mesoscopic metal-organic structure based on single-layer assembly of aluminium chains and organic alkylaryl spacers. The material markedly accelerates condensation reactions in water in the absence of acid or base Catalyst, as well as organocatalytic Michael-type reactions that also show superior enantioselectivity when comparing with the host-free transformation. The mesoscopic phase of the Solid allows for easy diffusion of products and the catalytic Solid is recycled and reused. Saturation transfer difference and two-dimensional (1)H nuclear Overhauser effect NOESY NMR spectroscopy show that non-covalent interactions are operative in these host-guest systems that account for substrate activation. The mesoscopic character of the host, its hydrophobicity and chemical stability in water, launch this material as a highly attractive supramolecular Catalyst to facilitate (asymmetric) transformations under more environmentally friendly conditions.
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Organic–inorganic supramolecular Solid Catalyst boosts organic reactions in water
Nature Communications, 2016Co-Authors: Pilar García-garcía, José María Moreno, Urbano Díaz, Marta Bruix, Avelino CormaAbstract:Coordination polymers and metal-organic frameworks are appealing synthetic hosts for mediating reactions. Here, the authors report a mesoscopic metal-organic structure that is shown to accelerate condensation reactions in water in the absence of acid or base, owing to the hydrophobic environment of the host. Coordination polymers and metal-organic frameworks are appealing as synthetic hosts for mediating chemical reactions. Here we report the preparation of a mesoscopic metal-organic structure based on single-layer assembly of aluminium chains and organic alkylaryl spacers. The material markedly accelerates condensation reactions in water in the absence of acid or base Catalyst, as well as organocatalytic Michael-type reactions that also show superior enantioselectivity when comparing with the host-free transformation. The mesoscopic phase of the Solid allows for easy diffusion of products and the catalytic Solid is recycled and reused. Saturation transfer difference and two-dimensional ^1H nuclear Overhauser effect NOESY NMR spectroscopy show that non-covalent interactions are operative in these host–guest systems that account for substrate activation. The mesoscopic character of the host, its hydrophobicity and chemical stability in water, launch this material as a highly attractive supramolecular Catalyst to facilitate (asymmetric) transformations under more environmentally friendly conditions.
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In Situ Preparation of a Multifunctional Chiral Hybrid Organic-Inorganic Catalyst for Asymmetric Multicomponent Reactions
Chemical Science, 2013Co-Authors: Pilar García-garcía, Urbano Díaz, Alexandre Zagdoun, Christophe Copéret, Anne Lesage, Avelino CormaAbstract:A chiral mesoporous organosilica material incorporating a urea based-cinchona derivative and propylamine groups was prepared by a co-condensation method. The multisite Solid Catalyst efficiently promoted the asymmetric multicomponent reaction of aldehydes, malonates and nitromethane
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Bifunctional Solid Catalysts for chemoselective hydrogenation-cyclisation-amination cascade reactions of relevance for the synthesis of pharmaceuticals
Tetrahedron, 2010Co-Authors: Antonio Leyva-pérez, Jose R. Cabrero-antonino, Avelino CormaAbstract:Abstract The benzodiazepines olanzapine and clozapine are nowadays manufactured by a three-step process with a final yield below 50%. An approach to environmentally-friendly intensive processes consists in the development of multifunctional Solid Catalyst able to catalyze multistep reactions. Here, a bifunctional metal-acid Solid Catalyst has been prepared and is able to carry out hydrogenation–cyclisation–amination reactions in a cascade process. The catalytic system is illustrated for the synthesis of these important antipsychotics, being an alternative for the current industrial process that requires three steps batch reactions, using mineral acids and bases, and stoichiometric amounts of SnCl2.
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multisite Solid Catalyst for cascade reactions the direct synthesis of benzodiazepines from nitro compounds
Chemistry: A European Journal, 2009Co-Authors: Maria J Climent, Avelino Corma, Sara Iborra, Laura L SantosAbstract:Substituted 1,5-benzodiazepines are selectively synthesized in one pot from substituted nitroaromatics and ketones. The reaction is performed in the presence of hydrogen and in the absence of solvent by using a bifunctional Solid Catalyst with a chemoselective hydrogenation functional group capable of reducing the nitro group to a diamino group and an acid functional group, which catalyzes the cyclocondensation of the amino group with the ketone.
P. Fongarland - One of the best experts on this subject based on the ideXlab platform.
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direct Solid lewis acid catalyzed wood liquefaction into lactic acid kinetic evidences that wood pretreatment might not be a prerequisite
Chemcatchem, 2017Co-Authors: Y. Swesi, C. Nguyen, F. Rataboul, M. Eternot, P. Fongarland, N. EssayemAbstract:The objective of the present work was to determine if wood sawdust can be used instead of isolated cellulose in the general Solid-acid-catalyzed production of chemicals. The kinetics of model cellulose and pine-wood sawdust liquefaction into lactic acid were determined in the presence of a Solid Lewis acid, ZrW. The catalytic hydrolysis of pine wood was performed at 190 °C in a large-scale batch reactor (2.5 L). Similar kinetic curves of lactic formation were obtained for cellulose and wood as substrates. Moreover, the initial lactic acid production rate of pine-wood sawdust was higher than that of model cellulose, proving that, in spite of the presence of lignin/hemicellulose, the Catalyst drives the transformation towards lactic acid formation. However, our results give also evidence of Solid-Catalyst deactivation for both cellulose and wood substrates. This result indicates that if wood pretreatment can be bypassed, the bottleneck will be the Solid-Catalyst regeneration and recycling.
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Direct Solid Lewis Acid Catalyzed Wood Liquefaction into Lactic Acid: Kinetic Evidences that Wood Pretreatment Might Not be a Prerequisite
ChemCatChem, 2017Co-Authors: Y. Swesi, C. Nguyen, F. Rataboul, M. Eternot, P. Fongarland, N. EssayemAbstract:The objective of the present work was to determine if wood sawdust can be used instead of isolated cellulose in the general Solid-acid-catalyzed production of chemicals. The kinetics of model cellulose and pine-wood sawdust liquefaction into lactic acid were determined in the presence of a Solid Lewis acid, ZrW. The catalytic hydrolysis of pine wood was performed at 190 degrees C in a large-scale batch reactor (2.5 L). Similar kinetic curves of lactic formation were obtained for cellulose and wood as substrates. Moreover, the initial lactic acid production rate of pine-wood sawdust was higher than that of model cellulose, proving that, in spite of the presence of lignin/hemicellulose, the Catalyst drives the transformation towards lactic acid formation. However, our results give also evidence of Solid-Catalyst deactivation for both cellulose and wood substrates. This result indicates that if wood pretreatment can be bypassed, the bottleneck will be the Solid-Catalyst regeneration and recycling.
C. Nguyen - One of the best experts on this subject based on the ideXlab platform.
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direct Solid lewis acid catalyzed wood liquefaction into lactic acid kinetic evidences that wood pretreatment might not be a prerequisite
Chemcatchem, 2017Co-Authors: Y. Swesi, C. Nguyen, F. Rataboul, M. Eternot, P. Fongarland, N. EssayemAbstract:The objective of the present work was to determine if wood sawdust can be used instead of isolated cellulose in the general Solid-acid-catalyzed production of chemicals. The kinetics of model cellulose and pine-wood sawdust liquefaction into lactic acid were determined in the presence of a Solid Lewis acid, ZrW. The catalytic hydrolysis of pine wood was performed at 190 °C in a large-scale batch reactor (2.5 L). Similar kinetic curves of lactic formation were obtained for cellulose and wood as substrates. Moreover, the initial lactic acid production rate of pine-wood sawdust was higher than that of model cellulose, proving that, in spite of the presence of lignin/hemicellulose, the Catalyst drives the transformation towards lactic acid formation. However, our results give also evidence of Solid-Catalyst deactivation for both cellulose and wood substrates. This result indicates that if wood pretreatment can be bypassed, the bottleneck will be the Solid-Catalyst regeneration and recycling.
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Direct Solid Lewis Acid Catalyzed Wood Liquefaction into Lactic Acid: Kinetic Evidences that Wood Pretreatment Might Not be a Prerequisite
ChemCatChem, 2017Co-Authors: Y. Swesi, C. Nguyen, F. Rataboul, M. Eternot, P. Fongarland, N. EssayemAbstract:The objective of the present work was to determine if wood sawdust can be used instead of isolated cellulose in the general Solid-acid-catalyzed production of chemicals. The kinetics of model cellulose and pine-wood sawdust liquefaction into lactic acid were determined in the presence of a Solid Lewis acid, ZrW. The catalytic hydrolysis of pine wood was performed at 190 degrees C in a large-scale batch reactor (2.5 L). Similar kinetic curves of lactic formation were obtained for cellulose and wood as substrates. Moreover, the initial lactic acid production rate of pine-wood sawdust was higher than that of model cellulose, proving that, in spite of the presence of lignin/hemicellulose, the Catalyst drives the transformation towards lactic acid formation. However, our results give also evidence of Solid-Catalyst deactivation for both cellulose and wood substrates. This result indicates that if wood pretreatment can be bypassed, the bottleneck will be the Solid-Catalyst regeneration and recycling.
