Characterization of autohydrolysis aspen (<i>P</i>. <i>tremuloides</i>) lignins. Part 3. Infrared and ultraviolet studies of extracted autohydrolysis lignin

Chua, Miranda G. S.; Wayman, Morris

doi:10.1139/v79-421

Cited by 50 publications

(38 citation statements)

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“…The increase of absorption with increasing time agrees with the predominance of lower molecular weight materials at longer times in agreement with the gpc studies. The carboxylic acid groups are attributed to the incorporation into the lignin of low molecular weight carboxylic acids generated by the hydrolysis of the corresponding esters; this has also been proposed in the studies of autohydrolysis wood lignins (18 The low absorption at 1700-1720 cm-I shown by the DI samples suggests that the P-keto groups appearing in the DSEI fraction participated in condensation reactions leading to the formation of DI materials. The absence of keto groups in the DI samples agrees with the low values of O/C, exhibited by the insoluble materials.…”

Section: Dbcussionmentioning

confidence: 57%

“…Previous studies of the reactions affecting lignin during autohydrolysis (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) have used wood, and thereby the wood carbohydrates or their deldvatives were present to react with the lignin. In order to avoid such reactions, it was decided to study the effects of autohydrolysis on isolated lignin.…”

Section: Introductionmentioning

confidence: 99%

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Autohydrolysis of aspen milled wood lignin

Lora¹,

Wayman²

1980

Can. J. Chem.

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669 (1980). In order to obtain further understanding of the nature of lignin reactions during autocatalysed hydrolysis (autohydrolysis) of wood, milled wood lignin (MWL) was isolated from aspen (Populus tremuloides) and treated under autohydrolysis conditions. By this means reactions of the lignin itself could be distinguished from those taking place between lignin and the carbohydrate or other components of the wood. The material after the reaction was separated into a dioxane insoluble fraction (DI), a dioxane soluble but ether insoluble fraction (DSEI), and an ether soluble fraction (ES). Studies were carried out on the DI and DSEI fractions; no direct study was made of the small ES fraction.The formation of DI material increased linearly during the first 7.5 min at 170°C and then levelled off. At the same time DSEI decreased and then levelled off. Gel permeation chromatography of the DSEI fraction suggested that during autohydrolysis there is an initial generation of low molecular weight fragments which recombine to form first a high molecular weight soluble fraction and from this the insoluble product. The DSEI fraction contained increased conjugated and unconjugated keto groups. Carboxylic acids were also detected; they have been attributed to the reincorporation of low molecular weight aromatic acids generated by the hydrolysis of the corresponding esters. The dioxane insoluble (DI) fraction had fewer unconjugated keto groups than the DSEI fraction, indicating that these groups participated in the condensation reactions leading to the formation of insoluble material. These probably involve position 6 of the aromatic ring. JAIRO H. LORA et MORRIS WAYMAN. Can. J. Chem. 58,669 (1980). Dans le but d'obtenir de plus amples informations sur la nature des reactions de la lignine lors de I'hydrolyse autocatalysee (autohydrolyse) du bois, on a isole du peuplier (Populus tremuloides) la lignine de bois moulu (LBM) et on l'a soumise a une autohydrolyse. Par ces reactions de la lignine on peut distinguer celles qui ont lieu entre la lignine et les carbohydrates ou d'autres derives du bois. Les produits de la reaction sont separes en fraction insoluble dans le dioxanne (ID), fraction soluble dans le dioxanne mais insoluble dans l'tther (SDIE) et en une fraction soluble dans l'ether (SE). On a etudie les fractions ID et SDIE mais on n'a pas fait d'etudes directes sur la petite fraction SE.La formation de produits ID augmente lineairement durant les 7.5 premieres minutes puis se stabilise. En mcme temps la fraction §DIE dirninue puis se stabilise. La chromatographie sur gel de la fraction SDIE suggere que lors de l'autohydrolyse il y aformation initiale de fragments de faibles poids moleculaires qui se recombinent d'abord pour donner la fraction soluble de poids moleculaire eleve e t a partir duquel se forme le produit insoluble. La fraction SDIE contient des groupes cetoniques conjugues et non conjugues. On a egalement decele des acides carboxyliques et on les attribue a la reincorporation d'acides aromatiques de faib...

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Section: Dbcussionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Autohydrolysis of aspen milled wood lignin

Lora¹,

Wayman²

1980

Can. J. Chem.

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“…It is well understood that lignin undergoes competing polymerization and depolymerization reactions under acidic conditions [68][69][70][71][72]. It was seen from our previous study that extensive cross-linking compromised tensile strength in lignin based adhesive blends [28].…”

Section: Use Of Recovered Reclpilot As An Antioxidantmentioning

confidence: 99%

Toward Complete Utilization of Miscanthus in a Hot-Water Extraction-Based Biorefinery

et al. 2017

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Miscanthus (Miscanthus sp. Family: Poaceae) was hot-water extracted (two h, at 160 • C) at three scales: laboratory (Parr reactor, 300 cm 3 ), intermediate (M/K digester, 4000 cm 3 ), and pilot (65 ft 3 -digester, 1.841 × 10 6 cm 3 ). Hot-water extracted miscanthus, hydrolyzate, and lignin recovered from hydrolyzate were characterized and evaluated for potential uses aiming at complete utilization of miscanthus. Effects of scale-up on digester yield, removal of hemicelluloses, deashing, delignification degree, lignin recovery and purity, and cellulose retention were studied. The scale-dependent results demonstrated that before implementation, hot-water extraction (HWE) should be evaluated on a scale larger than a laboratory scale. The production of energy-enriched fuel pellets from hot-water extracted miscanthus, especially in combination with recovered lignin is recommended, as energy of combustion increased gradually from native to hot-water extracted miscanthus to recovered lignin. The native and pilot-scale hot-water extracted miscanthus samples were also subjected to enzymatic hydrolysis using a cellulase-hemicellulase cocktail, to produce fermentable sugars. Hot-water extracted biomass released higher amount of glucose and xylose verifying benefits of HWE as an effective pretreatment for xylan-rich lignocellulosics. The recovered lignin was used to prepare a formaldehyde-free alternative to phenol-formaldehyde resins and as an antioxidant. Promising results were obtained for these lignin valorization pathways.

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“…This may be due to the condensation of aromatic rings of lignin with furfural (Chua and Wayman 1979). Therefore, the reduction of sugars dissolved in PEL under severe extraction conditions should result from the formation of furfural or its derivatives.…”

Section: Degradation and Conversion Of Carbohydrates The Content Of Dmentioning

confidence: 99%

“…At the same time, sugardegradation products such as furfural and hydroxymethyl furfural also have an influence on the condensation of lignin. Chua and Wayman (1979) observed an obvious condensation of lignin during HWE of the aspen wood, and they attributed this phenomenon to the reaction between lignin aromatic rings (with high charge density at C6), furfural, and hydroxymethyl furfural. In addition, the redeposition of dissolved lignin occurred along with increasing the extraction conditions (Mašura 1987).…”

Section: Introductionmentioning

confidence: 99%

Degradation and Redeposition of the Chemical Components of Aspen Wood during Hot Water Extraction

Chen

Wang

et al. 2015

BioResources

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Hot water extraction (HWE) prior to pulping of wood is a promising method in constructing a platform for traditional pulping or for biorefinery processing. In this study, HWE of aspen wood at a maximum reaction temperature (Treaction) between 140 and 180 ºC was investigated to obtain an optimal extraction condition for wood-derived products. The effect of extraction temperature and reaction time on the extraction performance of the chemical constituents was evaluated, and the degradation and redeposition of lignin and carbohydrates during the HWE process were assessed. Results showed that a minimum Treaction of 160 ºC was necessary for satisfactory carbohydrate removal. The dissolution and readsorption of sugars reached a balance, such that no more sugars in pre-extraction liquor (PEL) were adsorbed on the wood surface under more severe extraction conditions. The reduction of sugars dissolved in PEL should result from the formation of furfural or its derivatives. At the final extraction stage, the dissolved lignin in PEL could redeposit on the exothecium rather than the endothecium of the wood chips.

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Characterization of autohydrolysis aspen (P. tremuloides) lignins. Part 3. Infrared and ultraviolet studies of extracted autohydrolysis lignin

Cited by 50 publications

References 1 publication

Autohydrolysis of aspen milled wood lignin

Autohydrolysis of aspen milled wood lignin

Toward Complete Utilization of Miscanthus in a Hot-Water Extraction-Based Biorefinery

Degradation and Redeposition of the Chemical Components of Aspen Wood during Hot Water Extraction

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