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Acidolysis of wood in ionic liquids / Bin Li 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. 3126–3136 Titre : Acidolysis of wood in ionic liquids Type de document : texte imprimé Auteurs : Bin Li, Auteur ; Ilari Filpponen, Auteur ; Dimitris S. Argyropoulos, Auteur Année de publication : 2010 Article en page(s) : pp. 3126–3136 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Acidolysis  Wood  Ionic  Liquids Résumé : Three wood species including Eucalyptus grandis (E. grandis), Southern pine (S. pine), and Norway spruce thermomechanical pulp (N. spruce TMP) were dissolved in the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([Amim]Cl), and then they were pretreated with small amounts of hydrochloric acid, as a function of time. The materials regenerated from the IL solutions were determined to contain significantly higher amounts of lignin than the original wood. Detailed analyses of the recovered IL revealed the presence of typical wood degradation compounds, such as 5-hydroxymethylfurfural, furan-2-carboxylic acid, catechol, methylcatechol, methylguaiacol, acetoguaiacone, and acetol. The acidic pretreatment of these wood species in IL resulted in not only the near-complete hydrolysis of cellulose and hemicelluloses but also in a significant amount of lignin degradation. Aqueous reactions (under identical acid concentrations) showed a remarkably lower efficiency, demonstrating that ILs offer a unique environment for the acid-catalyzed dehydration chemistry, which is known to occur when polysaccharides and/or wood are subjected to an acid treatment. ISSN : 0885-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000983 [article] Acidolysis of wood in ionic liquids [texte imprimé] / Bin Li, Auteur ; Ilari Filpponen, Auteur ; Dimitris S. Argyropoulos, Auteur . - 2010 . - pp. 3126–3136. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3126–3136 Mots-clés : Acidolysis  Wood  Ionic  Liquids Résumé : Three wood species including Eucalyptus grandis (E. grandis), Southern pine (S. pine), and Norway spruce thermomechanical pulp (N. spruce TMP) were dissolved in the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([Amim]Cl), and then they were pretreated with small amounts of hydrochloric acid, as a function of time. The materials regenerated from the IL solutions were determined to contain significantly higher amounts of lignin than the original wood. Detailed analyses of the recovered IL revealed the presence of typical wood degradation compounds, such as 5-hydroxymethylfurfural, furan-2-carboxylic acid, catechol, methylcatechol, methylguaiacol, acetoguaiacone, and acetol. The acidic pretreatment of these wood species in IL resulted in not only the near-complete hydrolysis of cellulose and hemicelluloses but also in a significant amount of lignin degradation. Aqueous reactions (under identical acid concentrations) showed a remarkably lower efficiency, demonstrating that ILs offer a unique environment for the acid-catalyzed dehydration chemistry, which is known to occur when polysaccharides and/or wood are subjected to an acid treatment. ISSN : 0885-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1000983

Determination of cellulose reactivity by using phosphitylation and quantitative 31P NMR spectroscopy / Ilari Filpponen ; Dimitris S. Argyropoulos in Industrial & engineering chemistry research, Vol. 47 n°22 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8906–8910 Titre : Determination of cellulose reactivity by using phosphitylation and quantitative 31P NMR spectroscopy Type de document : texte imprimé Auteurs : Ilari Filpponen, Auteur ; Dimitris S. Argyropoulos, Auteur Année de publication : 2008 Article en page(s) : p. 8906–8910 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Cellulose  Phosphitylation Résumé : The phosphitylation of cellulose with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane [P(II)], is proposed as a means to determine its reactivity via an evaluation of its accessible hydroxyl groups. A variety of cellulose samples were subjected to this phosphitylation reaction, and the consumption of phosphitylation reagent was followed by quantitative 31P NMR spectroscopy. This consumption was found to be directly proportional to the amount of reactive hydroxyl groups on the cellulosic material. To further evaluate the quantitative reliability of this methodology, cellulose samples were subjected to a series of mechanical beating treatments, and the changes in the amount of accessible OH groups were evaluated. In addition, cellulose samples were equilibrated to various moisture contents, and their accessible OH groups were determined using the developed methodology. Both variables examined were found to affect the amount of reactive OH groups present on the samples with variations in the moisture content having a greater effect. For example, up to 6.5 mmol g−1, of accessible OH groups were found to be created within the highly refined samples at the highest moisture content. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800936x [article] Determination of cellulose reactivity by using phosphitylation and quantitative 31P NMR spectroscopy [texte imprimé] / Ilari Filpponen, Auteur ; Dimitris S. Argyropoulos, Auteur . - 2008 . - p. 8906–8910. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8906–8910 Mots-clés : Cellulose  Phosphitylation Résumé : The phosphitylation of cellulose with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane [P(II)], is proposed as a means to determine its reactivity via an evaluation of its accessible hydroxyl groups. A variety of cellulose samples were subjected to this phosphitylation reaction, and the consumption of phosphitylation reagent was followed by quantitative 31P NMR spectroscopy. This consumption was found to be directly proportional to the amount of reactive hydroxyl groups on the cellulosic material. To further evaluate the quantitative reliability of this methodology, cellulose samples were subjected to a series of mechanical beating treatments, and the changes in the amount of accessible OH groups were evaluated. In addition, cellulose samples were equilibrated to various moisture contents, and their accessible OH groups were determined using the developed methodology. Both variables examined were found to affect the amount of reactive OH groups present on the samples with variations in the moisture content having a greater effect. For example, up to 6.5 mmol g−1, of accessible OH groups were found to be created within the highly refined samples at the highest moisture content. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800936x

Toward thermoplastic lignin polymers. Part 1. / Hasan Sadeghifar in Industrial & engineering chemistry research, Vol. 51 N° 51 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16713–16720 Titre : Toward thermoplastic lignin polymers. Part 1. : Selective masking of phenolic hydroxyl groups in kraft lignins via methylation and oxypropylation chemistries Type de document : texte imprimé Auteurs : Hasan Sadeghifar, Auteur ; Chengzhong Cui, Auteur ; Dimitris S. Argyropoulos, Auteur Année de publication : 2012 Article en page(s) : pp. 16713–16720 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermoplastic  Hydroxyl Résumé : This work offers a comprehensive understanding of the conditions required for the selective masking of the phenolic hydroxyl groups in technical kraft lignins, which is pivotal in determining their subsequent chemical and thermal reactivity. To this effect, we have examined the chemistry and developed the conditions for the facile, mild, and selective masking of the phenolic hydroxyl groups in softwood and hardwood kraft lignins. We have compared two series of methylated softwood kraft lignins synthesized using different methylation chemistries. Our data show that (when used as specified) dimethyl sulfate in aqueous NaOH selectively converts the phenolic hydroxyl groups of kraft lignin to its methylated derivatives without apparent side reactions. In contrast, methyl iodide (in the presence of excess K2CO3 in N,N-dimethylformamide) was found to be rather ineffective and unselective. Various milder methylation conditions were also examined for both softwood and hardwood kraft lignins using dimethyl sulfate, and the details of this work are documented. In addition, a series of oxypropylation reactions were also carried out using propylene oxide in aqueous NaOH. Propylene oxide was shown to selectively add (at room temperature, 0.5 M NaOH, 18 h) less than two units on average per phenolic hydroxyl group without significant additional polymerization or other side reactions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301848j [article] Toward thermoplastic lignin polymers. Part 1. : Selective masking of phenolic hydroxyl groups in kraft lignins via methylation and oxypropylation chemistries [texte imprimé] / Hasan Sadeghifar, Auteur ; Chengzhong Cui, Auteur ; Dimitris S. Argyropoulos, Auteur . - 2012 . - pp. 16713–16720. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16713–16720 Mots-clés : Thermoplastic  Hydroxyl Résumé : This work offers a comprehensive understanding of the conditions required for the selective masking of the phenolic hydroxyl groups in technical kraft lignins, which is pivotal in determining their subsequent chemical and thermal reactivity. To this effect, we have examined the chemistry and developed the conditions for the facile, mild, and selective masking of the phenolic hydroxyl groups in softwood and hardwood kraft lignins. We have compared two series of methylated softwood kraft lignins synthesized using different methylation chemistries. Our data show that (when used as specified) dimethyl sulfate in aqueous NaOH selectively converts the phenolic hydroxyl groups of kraft lignin to its methylated derivatives without apparent side reactions. In contrast, methyl iodide (in the presence of excess K2CO3 in N,N-dimethylformamide) was found to be rather ineffective and unselective. Various milder methylation conditions were also examined for both softwood and hardwood kraft lignins using dimethyl sulfate, and the details of this work are documented. In addition, a series of oxypropylation reactions were also carried out using propylene oxide in aqueous NaOH. Propylene oxide was shown to selectively add (at room temperature, 0.5 M NaOH, 18 h) less than two units on average per phenolic hydroxyl group without significant additional polymerization or other side reactions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301848j