Kraft lignin fractionation by organic solvents: Correlation between molar mass and higher heating value

Araújo, Luísa Carvalho Pereira; Yamaji, Fábio Minoru; Lima, Vitor; Botaro, Vagner Roberto

doi:10.1016/j.biortech.2020.123757

Cited by 46 publications

(31 citation statements)

References 29 publications

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“…This yield is not high compared to the lignin content (20 -30%) in lignocellulosic materials. However, it is in agreement with the previous study proving that lignin's yield strongly depends on the value of pH treatment [24].…”

Section: Lignin Productionsupporting

confidence: 93%

“…Indeed, the conversion of the lignin's fractions is easier than real lignin 22 . Therefore, lignin's fractionation is very interested in recent years 23,24 , in which lignin can be fractionated into different fractions with different molecular weights [23][24][25] . The lignin's fractions with different molecular weights can be applied for different purposes and transformed into chemicals and fuels with a suitable condition.…”

Section: Introductionmentioning

confidence: 99%

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Fractionation of lignin produced from the Earleaf Acacia tree by sequential industrial organic solvents

Nguyen

et al. 2021

Sci. Tech. Dev. J.

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Introduction: Understanding the fractions of lignin is important for further conversion of lignin into valuable products. Herein, the “home-made” lignin from Earleaf Acacia tree was extracted by sequential industrial organic solvent and characterized each fraction to reveal its properties for further catalytic applications. Methods: In this work, lignin was prepared from the Earleaf Acacia tree using the soda method. Then, the prepared lignin was fractionated by sequential solvents of ethyl acetate, ethanol, methanol, and acetone. Each lignin fractions were characterized by FT-IR and GPC. Results: The FT-IR results confirmed the soda method can produce lignin from woodchips. The fractionation of lignin separated the lignin mixture into different molecular weight fraction from light – medium into heavy compounds. Conclusion: Lignin was produced from woodchips using the soda method successfully. The fractionation using the sequential organic solvents showed the separation of different molecular weight of lignin, which allow to apply for the further conversion into useful products.

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Section: Lignin Productionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Fractionation of lignin produced from the Earleaf Acacia tree by sequential industrial organic solvents

Nguyen

et al. 2021

Sci. Tech. Dev. J.

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“…The stretching vibration peak of -OH in the cellulose, hemicellulose, and lignin was at 3405 cm −1 ; it was a broad peak for lignin, and the absorption of lignins of high CDF (>4000) has low intensity, which means the hydroxyl groups decreased. At 2940 cm −1 , there are CH stretching vibration absorption peaks of the methyl group, methylene group and methine group, and the absorption intensity varied a little as well [ 31 , 32 ]. At 1655 cm −1 , there is the conjugated C=O stretching vibration absorption peak, where the absorption peak is reduced, indicating that the relative content of p-hydroxy phenylpropane units is low.…”

Section: Resultsmentioning

confidence: 99%

“…TG and DTG profiles are shown in Figure 9 . The thermal stability of lignin can be expressed by the maximum weight loss rate of lignin [ 31 , 32 ]. The maximum weight loss temperature of the hydrotropic lignin is basically in the range of 330–350 °C; this is due to the complex structure of lignin with phenolic hydroxyl and carbonyl groups and benzylic hydroxyl.…”

Section: Resultsmentioning

confidence: 99%

Valorization of Rice Straw via Hydrotropic Lignin Extraction and Its Characterization

Yin

Wang

et al. 2021

Molecules

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Rice straw hydrotropic lignin was extracted from p-Toluene sulfonic acid (p-TsOH) fractionation with a different combined delignification factor (CDF). Hydrotropic lignin characterization was systematically investigated, and alkaline lignin was also studied for the contrast. Results showed that the hydrotropic rice straw lignin particle was in nanometer scopes. Compared with alkaline lignin, the hydrotropic lignin had greater molecular weight. NMR analysis showed that β-aryl ether linkage was well preserved at low severities, and the unsaturation in the side chain of hydrotropic lignin was high. H units and G units were preferentially degraded and subsequently condensed at high severity. High severity also resulted in the cleavage of part β-aryl ether linkage. 31P-NMR showed the decrease in aliphatic hydroxyl groups and the increasing carboxyl group content at high severity. The maximum weight loss temperature of the hydrotropic lignin was in the range of 330–350 °C, higher than the alkaline lignin, and the glass conversion temperature (Tg) of the hydrotropic lignin was in the range of 107–125 °C, lower than that of the alkaline lignin. The hydrotropic lignin has high β-aryl ether linkage content, high activity, nanoscale particle size, and low Tg, which is beneficial for its further valorization.

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“…The content of each element of the EHL was analyzed using an Elemantar Vario EL cube (Elementar Analysensysteme GmbH, Langenselbold, Germany) organic elemental analyzer. EHL was acetylated according to the method of Pereira Araujo et al [ 23 ]. The molecular weight of EHL was analyzed using ambient gel permeation chromatograph (GPC, Agilent PL-GPC50 am, Agilent Technologies, Inc., Santa Clara, CA, USA) with polystyrene (PS) specimens with molecular weights of 6,570,000, 3,152,000, 920,000, 468,300, 9820, 4910, 1300, 580 and 162 g/mol.…”

Section: Methodsmentioning

confidence: 99%

Preparation of Molded Fiber Products from Hydroxylated Lignin Compounded with Lewis Acid-Modified Fibers Its Analysis

et al. 2021

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In this study, molded fiber products (MFPs) were prepared from lignin compounded with Lewis acid-modified fibers using enzymatic hydrolysis lignin (EHL) as a bio-phenol. The fibers were modified and compounded entirely through hot-pressing. To improve the reactivity of enzymatic lignin, hydroxylated enzymatic hydrolysis lignin (HEHL) was prepared by hydroxylation modification of purified EHL with hydrogen peroxide (H2O2) and ferrous hydroxide (Fe(OH)3). HEHL was mixed uniformly with Lewis acid-modified fibers on a pressure machine and modified during the molding process. The purpose of Lewis acid degradation of hemicellulose-converted furfural with HEHL was to generate a resin structure to improve the mechanical properties of a MFPs. The microstructure of the MFP was shown to be generated by resin structure, and it was demonstrated that HEHL was compounded on Lewis acid-modified fibers during the molding process. The thermal stability of the MFP with composite HEHL did not change significantly owing to the addition of lignin and had higher tensile strength (46.28 MPa) and flexural strength (65.26 MPa) compared to uncompounded and modified MFP. The results of this study are expected to promote the application of high lignin content fibers in molded fibers.

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Kraft lignin fractionation by organic solvents: Correlation between molar mass and higher heating value

Cited by 46 publications

References 29 publications

Fractionation of lignin produced from the Earleaf Acacia tree by sequential industrial organic solvents

Fractionation of lignin produced from the Earleaf Acacia tree by sequential industrial organic solvents

Valorization of Rice Straw via Hydrotropic Lignin Extraction and Its Characterization

Preparation of Molded Fiber Products from Hydroxylated Lignin Compounded with Lewis Acid-Modified Fibers Its Analysis

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