Documents disponibles écrits par cet auteur

Demonstration of a process for the conversion of kraft lignin into vanillin and methyl vanillate by acidic oxidation in aqueous methanol / Voitl, Tobias in Industrial & engineering chemistry research, Vol. 49 N° 2 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 520–525 Titre : Demonstration of a process for the conversion of kraft lignin into vanillin and methyl vanillate by acidic oxidation in aqueous methanol Type de document : texte imprimé Auteurs : Voitl, Tobias, Auteur ; von Rohr, Philipp Rudolf, Auteur Année de publication : 2010 Article en page(s) : pp 520–525 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Conversion  Kraft  Oxidation  Aqueous  methanol. Résumé : In this work, a process for producing vanillin and methyl vanillate from an industrial kraft lignin by oxidation in aqueous methanol at acidic pH is proposed. A series of consecutive runs, comprising the steps of kraft lignin oxidation, monomer extraction, and filtration of residual lignin, were conducted. The depolymerization of kraft lignin (1 g per run) was carried out in a stirred batch reactor with 80 vol % methanol/water as the solvent, with H3PMo12O40 as a homogeneous catalyst, and with 10 bar of oxygen initially present. The monomeric products were recovered from the process by extraction with chloroform and quantified by gas chromatography/mass spectrometry (GC/MS). Residual kraft lignin was recovered from the reaction medium by filtration. After extraction and filtration, the reaction medium, containing the homogeneous catalyst, was reused in the next run. The sum of all quantified products (gas phase, extract, and solids), as well as the amount of consumed oxygen, reached constant levels after five runs, and no indications of catalyst deactivation were found. Extracted products containing vanillin (3.5 wt %) and methyl vanillate (3.5 wt %) were recovered with a yield of 65 wt %. The extracted products were further analyzed by size exclusion chromatography (SEC) and Fourier transform infrared (FTIR) spectroscopy regarding their average molecular weight and functional group contents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901293p [article] Demonstration of a process for the conversion of kraft lignin into vanillin and methyl vanillate by acidic oxidation in aqueous methanol [texte imprimé] / Voitl, Tobias, Auteur ; von Rohr, Philipp Rudolf, Auteur . - 2010 . - pp 520–525. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 520–525 Mots-clés : Conversion  Kraft  Oxidation  Aqueous  methanol. Résumé : In this work, a process for producing vanillin and methyl vanillate from an industrial kraft lignin by oxidation in aqueous methanol at acidic pH is proposed. A series of consecutive runs, comprising the steps of kraft lignin oxidation, monomer extraction, and filtration of residual lignin, were conducted. The depolymerization of kraft lignin (1 g per run) was carried out in a stirred batch reactor with 80 vol % methanol/water as the solvent, with H3PMo12O40 as a homogeneous catalyst, and with 10 bar of oxygen initially present. The monomeric products were recovered from the process by extraction with chloroform and quantified by gas chromatography/mass spectrometry (GC/MS). Residual kraft lignin was recovered from the reaction medium by filtration. After extraction and filtration, the reaction medium, containing the homogeneous catalyst, was reused in the next run. The sum of all quantified products (gas phase, extract, and solids), as well as the amount of consumed oxygen, reached constant levels after five runs, and no indications of catalyst deactivation were found. Extracted products containing vanillin (3.5 wt %) and methyl vanillate (3.5 wt %) were recovered with a yield of 65 wt %. The extracted products were further analyzed by size exclusion chromatography (SEC) and Fourier transform infrared (FTIR) spectroscopy regarding their average molecular weight and functional group contents. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901293p

Reply to “comments on ‘demonstration of a process for the conversion of kraft lignin into vanillin and methyl vanillate by acidic oxidation in aqueous methanol’” / Voitl, Tobias in Industrial & engineering chemistry research, Vol. 49 N° 7 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3501–3503 Titre : Reply to “comments on ‘demonstration of a process for the conversion of kraft lignin into vanillin and methyl vanillate by acidic oxidation in aqueous methanol’” Type de document : texte imprimé Auteurs : Voitl, Tobias, Auteur ; von Rohr, Philipp Rudolf, Auteur Année de publication : 2010 Article en page(s) : pp. 3501–3503 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Demonstration  Kraft  Lignin  Vanillin  Methyl  Vanillate  Acidic  Oxidation  Aqueous  Methanol ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100313f [article] Reply to “comments on ‘demonstration of a process for the conversion of kraft lignin into vanillin and methyl vanillate by acidic oxidation in aqueous methanol’” [texte imprimé] / Voitl, Tobias, Auteur ; von Rohr, Philipp Rudolf, Auteur . - 2010 . - pp. 3501–3503. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3501–3503 Mots-clés : Demonstration  Kraft  Lignin  Vanillin  Methyl  Vanillate  Acidic  Oxidation  Aqueous  Methanol ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100313f