Precipitation Fractionation

Francuskiewicz, Frieder

doi:10.1007/978-3-642-78704-1_5

Cited by 4 publications

(9 citation statements)

References 8 publications

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“…GPC findings confirmed that lignin fractionation was predominantly influenced by lignin molecular weight. The GPC profiles exhibited a marked shift towards lower molecular mass material with increasing anti-solvent addition, in agreement with previous reports from organic solvent and fractional precipitation studies 4,[13][14][15] . Lignin with higher molecular weights were obtained after the addition of 0.25 to 1 eq of water, with a large proportion of material having molar mass > 30000 g mol -1 .…”

Section: Molecular Weight Characterization By Gpcsupporting

confidence: 92%

“…8 A fractional precipitation scheme for lignin was first proposed by Cui et al, 14 based on partial solubility of lignin polymers in a solvent/antisolvent mixture. 15 They demonstrated the use of a continuous solvent gradient involving two miscible organic solvents, one being a good solvent for Kraft lignin (acetone) and the other poor (hexane). A relatively monodisperse fraction with Mw of 1500 g/mol and polydispersity approaching 1.1 was successfully isolated in yields ranging between 10 and 20% w/w.…”

Section: ■ Introductionmentioning

confidence: 99%

“…An alternative method is dissolving lignin in a pure or aqueous solvent, followed by fractional precipitation using an anti-solvent 8 . A fractional precipitation scheme for lignin was first proposed by Cui et al 14 , based on partial solubility of lignin polymers in a solvent/anti-solvent mixture 15 . They demonstrated the use of a continuous solvent gradient involving two miscible organic solvents, one being a good solvent for Kraft lignin (acetone) and the other poor (hexane).…”

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Fractionation by Sequential Antisolvent Precipitation of Grass, Softwood, and Hardwood Lignins Isolated Using Low-Cost Ionic Liquids and Water

Chambon

Fitriyanti

Verdía

et al. 2020

ACS Sustainable Chem. Eng.

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In this study, fractionation by sequential anti-solvent precipitation was applied to ionoSolv lignins for the first time. Pretreatment with the aqueous low-cost protic ionic liquid N,Ndimethylbutylammonium hydrogen sulfate ([DMBA][HSO 4 ], 80 wt% in water) was applied to Miscanthus (herbaceous), willow (hardwood) and pine (softwood) to extract lignin.Then, lignin was sequentially precipitated by addition of water as anti-solvent.Fractionation appeared to be controlled by molecular weight of lignin polymers. Fractions isolated with minimal water volumes were shown to have high molecular weight, polydispersity, thermal stability and T g (178 °C). Later precipitates were more monodisperse, had high phenolic and total hydroxyl content, lower thermal stability and T g (136 °C). Addition of 1 g of water per g of dry IL was able to precipitate up to 90 wt% Page 2 of 52 ACS Paragon Plus Environment ACS Sustainable Chemistry & Engineering 3 of lignin. Fractional precipitation represents a novel lignin isolation technique that can be performed as part of the lignin recovery procedure enabling a high degree of control of lignin properties. The effect of the fractionation on lignin structural, chemical and thermal properties was thoroughly examined by 2D HSQC NMR, GPC, TGA and DSC and compared to the unfractionated lignin precipitate obtained by addition of an excess of water.

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Section: Molecular Weight Characterization By Gpcsupporting

confidence: 92%

Section: ■ Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Fractionation by Sequential Antisolvent Precipitation of Grass, Softwood, and Hardwood Lignins Isolated Using Low-Cost Ionic Liquids and Water

Chambon

Fitriyanti

Verdía

et al. 2020

ACS Sustainable Chem. Eng.

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“…To date, three different fractionation approaches have been applied that include sequential organic solvent extraction (most frequent), selective precipitation at reduced pH values, and membrane ultrafiltration. ,− Mörck et al adopted a series of solvents to extract both softwood and hardwood kraft lignins in an order of an increasing Hildebrand Solubility Parameter, and Thring et al extracted Alcell hardwood lignin into fractions with solvents of increasing hydrogen-bonding capability in both cases with remarkable results. Major limitations, however, are imposed by the sequential solvent extraction approach because only a limited set of available solvent types exist offering only limited possibilities of fractionation.…”

Section: Introductionmentioning

confidence: 99%

“…The work described in this effort embarks from our view that economical and industrially feasible processes for lignin fractionation are essential for consistently delivering homogeneous reactive polyphenols of well-defined narrow molecular weight polymers and oligomers based on lignin. Consequently, we developed a novel fractionation methodology that is used for synthetic polymers but largely neglected for technical lignins best described as fractional precipitation. , …”

Section: Introductionmentioning

confidence: 99%

Fractional Precipitation of Softwood Kraft Lignin: Isolation of Narrow Fractions Common to a Variety of Lignins

Cui

Sun

Argyropoulos

2014

ACS Sustainable Chem. Eng.

182

189

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In a manner similar to crude oil, technical lignins need refining if their potential as reactive polyphenols of well-defined molecular weight polymers and oligomers is to be actualized. In this paper, we demonstrate that a continuum of narrow fractions can be isolated by the incremental addition of a nonpolar solvent (hexanes) in a polar (acetone) solution of softwood wood kraft lignin. Three distinct commercial samples of softwood kraft lignin were used to examine the validity of the developed protocol using detailed chromatographic and quantitative functional group analytical methods. It was shown that all samples contain a common relatively monodisperse fraction of a polyphenolic material that can be isolated from the different lignins in yields ranging between 10 and 20% w/w. The versatility of the developed fractional precipitation protocol was further validated by creating artificial physical mixtures of the examined lignins in different proportions and isolating from them precisely calculated fractions of nearly identical molecular weight distributions and composition. Overall, the fractional precipitation approach described here offers the possibility that representative specific narrow fractions, common to a variety of softwood kraft lignins, can be isolated irrespective of the manufacturing details of the pulping process. As such, the otherwise known heterogeneous kraft lignin material, whose composition is relatively unpredictable due to manufacturing variations in making pulp, may now offer consistently homogeneous lignin streams with significant commercial ramifications.

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Structural Characterization of Rubber from Jackfruit and Euphorbia as a Model of Natural Rubber

et al. 2004

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A structural study of low molecular weight rubbers from Jackfruit (Artocarpus heterophyllus) and Painted spurge (Euphorbia heterophylla) was carried out as model compounds of natural rubber from Hevea brasiliensis. The rubber content of latex from Jackfruit was 0.4-0.7%, which is very low compared with that of 30-35% in the latex from Hevea tree. The rubber from Jackfruit latex was low molecular weight with narrow unimodal molecular weight distribution (MWD), whereas that obtained from E. heterophylla showed very broad MWD. The 1H and 13C NMR analyses showed that Jackfruit rubber consists of a dimethylallyl group and two trans-isoprene units connected to a long sequence of cis-isoprene units. The alpha-terminal group of Jackfruit rubber was presumed to be composed of a phosphate group based on the presence of 1H NMR signal at 4.08 ppm corresponding to the terminal =CH-CH2OP group.

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Precipitation Fractionation

Cited by 4 publications

References 8 publications

Fractionation by Sequential Antisolvent Precipitation of Grass, Softwood, and Hardwood Lignins Isolated Using Low-Cost Ionic Liquids and Water

Fractionation by Sequential Antisolvent Precipitation of Grass, Softwood, and Hardwood Lignins Isolated Using Low-Cost Ionic Liquids and Water

Fractional Precipitation of Softwood Kraft Lignin: Isolation of Narrow Fractions Common to a Variety of Lignins

Structural Characterization of Rubber from Jackfruit and Euphorbia as a Model of Natural Rubber

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