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Modeling the lignin degradation kinetics in an ethanol / formic acid solvolysis approach. Part 1. / James R. Gasson in Industrial & engineering chemistry research, Vol. 51 N° 32 (Août 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 32 (Août 2012) . - pp. 10595-10606 Titre : Modeling the lignin degradation kinetics in an ethanol / formic acid solvolysis approach. Part 1. : Kinetic model development Type de document : texte imprimé Auteurs : James R. Gasson, Auteur ; Daniel Forchheim, Auteur ; Tatjana Sutter, Auteur Année de publication : 2012 Article en page(s) : pp. 10595-10606 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetic  model  Kinetics  Modeling Résumé : A formal kinetic model describing the main reaction pathways yielding demethoxylated monomeric phenols from wheat straw lignin in a hydrogen-enriched solvolysis reaction system using ethanol as cosolvent has been developed. The simplified lump model combines both a detailed focus on the deoxygenation reactions at molecular level as well as the reactions of global bulk lumps. The results show that depolymerization of lignin structures is quickly achieved and that deoxygenation reactions largely follow a main route pathway via intermediate methoxyphenols and catechols to give stable phenols in the liquid phase. Observed ethyl group substituents of phenolics are seen to originate from either alkylation reactions of the intermediates, or directly from the depolymerizing structures. A high correlation between primary 4-ethylphenol products and para-coumaryl units in the examined lignin suggests that main reaction pathways are strongly dependent on the type of plant lignin used. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26259763 [article] Modeling the lignin degradation kinetics in an ethanol / formic acid solvolysis approach. Part 1. : Kinetic model development [texte imprimé] / James R. Gasson, Auteur ; Daniel Forchheim, Auteur ; Tatjana Sutter, Auteur . - 2012 . - pp. 10595-10606. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 32 (Août 2012) . - pp. 10595-10606 Mots-clés : Kinetic  model  Kinetics  Modeling Résumé : A formal kinetic model describing the main reaction pathways yielding demethoxylated monomeric phenols from wheat straw lignin in a hydrogen-enriched solvolysis reaction system using ethanol as cosolvent has been developed. The simplified lump model combines both a detailed focus on the deoxygenation reactions at molecular level as well as the reactions of global bulk lumps. The results show that depolymerization of lignin structures is quickly achieved and that deoxygenation reactions largely follow a main route pathway via intermediate methoxyphenols and catechols to give stable phenols in the liquid phase. Observed ethyl group substituents of phenolics are seen to originate from either alkylation reactions of the intermediates, or directly from the depolymerizing structures. A high correlation between primary 4-ethylphenol products and para-coumaryl units in the examined lignin suggests that main reaction pathways are strongly dependent on the type of plant lignin used. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26259763

Modeling the lignin degradation kinetics in a ethanol/formic acid solvolysis approach. Part 2. / Daniel Forchheim in Industrial & engineering chemistry research, Vol. 51 N° 46 (Novembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 46 (Novembre 2012) . - pp. 15053-15063 Titre : Modeling the lignin degradation kinetics in a ethanol/formic acid solvolysis approach. Part 2. : Validation and transfer to variable conditions Type de document : texte imprimé Auteurs : Daniel Forchheim, Auteur ; James R. Gasson, Auteur ; Ursel Hornung, Auteur Année de publication : 2013 Article en page(s) : pp. 15053-15063 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics  Modeling Résumé : A formal kinetic model treating the depolymerization and hydrodeoxygenation of wheat straw lignin in ethanol with formic acid as hydrogen source developed by Gasson et al. [Gasson et al. Ind. Eng. Chem. Res. 2012, 51 (32), 10595-10606J is validated and its applicability in a continuous stirred tank reactor (CSTR) at varying temperatures between 633 K and 673 K is tested. The fitted formal kinetic rate coefficients are compared and sensitivity and flux analyses are performed. Activation energies are estimated for the lumped reactions. The depolymerization to primary products is considerably accelerated when transferring the reaction from batch to a continuous operation. Higher heating rates and continuous feeding of the hydrogen donor formic acid aid in suppressing both gas and char production. Repolymerization of intermediate phenolic compounds is suppressed, which is suggested to be due to the interaction of intermediate and final products. The evaluation shows that a continuous system can aid in avoiding further gasification and charring of the intermediate products in this one-step lignin depolymerization deoxygenation reaction for the production of a phenol-rich bio-oil. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26679624 [article] Modeling the lignin degradation kinetics in a ethanol/formic acid solvolysis approach. Part 2. : Validation and transfer to variable conditions [texte imprimé] / Daniel Forchheim, Auteur ; James R. Gasson, Auteur ; Ursel Hornung, Auteur . - 2013 . - pp. 15053-15063. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 46 (Novembre 2012) . - pp. 15053-15063 Mots-clés : Kinetics  Modeling Résumé : A formal kinetic model treating the depolymerization and hydrodeoxygenation of wheat straw lignin in ethanol with formic acid as hydrogen source developed by Gasson et al. [Gasson et al. Ind. Eng. Chem. Res. 2012, 51 (32), 10595-10606J is validated and its applicability in a continuous stirred tank reactor (CSTR) at varying temperatures between 633 K and 673 K is tested. The fitted formal kinetic rate coefficients are compared and sensitivity and flux analyses are performed. Activation energies are estimated for the lumped reactions. The depolymerization to primary products is considerably accelerated when transferring the reaction from batch to a continuous operation. Higher heating rates and continuous feeding of the hydrogen donor formic acid aid in suppressing both gas and char production. Repolymerization of intermediate phenolic compounds is suppressed, which is suggested to be due to the interaction of intermediate and final products. The evaluation shows that a continuous system can aid in avoiding further gasification and charring of the intermediate products in this one-step lignin depolymerization deoxygenation reaction for the production of a phenol-rich bio-oil. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26679624