Effect of ultrasound on the physicochemical properties of organosolv lignins from wheat straw

Sun, Run‐Cang; Sun, Xiaofang; Xu, Xiangya

doi:10.1002/app.10670

Cited by 27 publications

(21 citation statements)

References 38 publications

(42 reference statements)

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“…However, there appeared to be no discernable trend within our results. Based on the nitrobenzene oxidation data, the relatively low S/G ratio could mean that lignin fractions with more guaiacyl units were easier to extract than the lignin fractions with more syringyl units or that the guaiacyl units were less condensed or cross linked than the syringyl units [ 33 , 34 ].…”

Section: Resultsmentioning

confidence: 99%

Characteristics of Lignin from Flax Shives as Affected by Extraction Conditions

Ross

Mazza

2010

IJMS

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Lignin, a polyphenolic molecule, is a major constituent of flax shives. This polyphenolic molecular structure renders lignin a potential source of a variety of commercially viable products such as fine chemicals. This work compares the performance of different lignin isolation methods. Lignin from flax shive was isolated using both conventional alkaline extraction method and a novel experimental pressurized low polarity water (PLPW) extraction process. The lignin yields and chemical composition of the lignin fractions were determined. The conventional alkali treatment with 1.25 M NaOH, heated at 80 °C for 5 h, extracted 92 g lignin per kg flax shives, while lignin yields from the PLPW extracts ranged from 27 to 241 g lignin per kg flax shives. The purity and monomeric composition of the lignins obtained from the different extraction conditions was assessed via UV spectroscopy and alkaline nitrobenzene oxidation. Lignin obtained from conventional alkali treatment with 1.25 M NaOH, heated at 80 °C for 5 h was of low purity and exhibited the lowest yields of nitrobenzene oxidation products. With respect to alkali assisted PLPW extractions, temperature created an opposing effect on lignin yield and nitrobenzene oxidation products. More lignin was extracted as temperature increased, yet the yield of nitrobenzene oxidation products decreased. The low yield of nitrobenzene oxidation products may be attributed to either the formation of condensed structures or the selective dissolution of condensed structures of lignin during the pressurized alkaline high temperature treatment. Analytical pyrolysis, using pyroprobe GC-MS, was used to investigate the molecular composition of the lignin samples. The total yield of pyrolysis lignin products was 13.3, 64.7, and 30.5% for the 1.25 M NaOH extracted lignin, alkaline assisted PLPW extracted lignin, and the unprocessed flax shives, respectively. Key lignin derived compounds such as guaiacol, 4-vinyl guaiacol, 4-methyl guaiacol, syringol, eugenol, isoeugenol, catechol, homocatechol, and vanillin were detected in all of the samples.

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Section: Resultsmentioning

confidence: 99%

Characteristics of Lignin from Flax Shives as Affected by Extraction Conditions

Ross

Mazza

2010

IJMS

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“…Yield of Crude and Purified Cellulose. Environmental concerns in the pulp industry have forced the removal of elemental chlorine from both delignification and bleaching processes, and this has enable the use of organic solvent and alkaline peroxide to become an industrial reality (22). Organic solvent based on delignification provides an interesting alternative to the commercial technologies used for chemical pulp manufacture.…”

Section: Resultsmentioning

confidence: 99%

“…The residue was filtered off and washed thoroughly with water and methanol until the filtrate was neutral. The solubilized hemicelluloses and lignin in the supernatants were isolated by a two step precipitation method and were characterized as previously reported ( , ). The remaining hemicelluloses and lignin were extracted from the eight corresponding residues with 2% H 2 O 2 −0.2% TAED (tetraacetylethylenediamine) at pH 11.8 for 12 h at 48 °C, respectively.…”

Section: Methodsmentioning

confidence: 99%

Comparative Study of Crude and Purified Cellulose from Wheat Straw

Sun

et al. 2004

J. Agric. Food Chem.

119

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A sequential totally chlorine-free procedure for isolation of cellulose from wheat straw was proposed in this study. The dewaxed straw was pretreated with 0.5 M NaOH in 60% methanol at 60 degrees C for 2.5 h under ultrasonic irradiation for 0-35 min and sequentially posttreated with 2% H(2)O(2)-0.2% TAED at pH 11.8 for 12 h at 48 degrees C, which together solubilized 85.3-86.1% of the original hemicelluloses and 91.7-93.2% of the original lignin, respectively. The yield of crude cellulose ranged between 46.2 and 49.2% on a dry weight basis related to wheat straw, which contained 11.2-12.2% residual hemicelluloses and 2.5-2.9% remaining lignin. Further treatment of the corresponding crude cellulosic preparations with 80% acetic acid-70% nitric acid under the condition given yielded 36.8-37.7% of the purified cellulose, which contained minor amounts of bound hemicelluloses (2.5-2.8%) and was relatively free of associated lignin (0.1-0.2%). The isolated crude and purified cellulose samples were comparatively studied by FT-IR and CP/MAS (13)C NMR spectroscopy, and the relative crystallinity was also estimated. The final stage treatment with 80% acetic acid-70% nitric acid decreased the hemicelluloses and lignin associated in the crude cellulose but led to 3.1-5.4% degradation of the original cellulose; in addition, the purity of the obtained cellulose was high. However, it was found that the final stage treatment is not severe enough to cause decrystallization of cellulose. The thermal stability of the purified cellulose is higher than that of the corresponding crude cellulose.

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“…Isolation of lignin has been investigated using alkali or acidic solutions and organic solvents as well as steam explosion from cereal straws, such as wheat straw 10,11 and rice straw, 12 and these strong physic and chemical methods have resulted in the structural change of macromolecule, therefore they cannot used as a standard method for isolation and characterization of lignin polymer. MS and SCB are the most abundant residues from agricultural industry in the world.…”

Section: Introductionmentioning

confidence: 99%

Extraction and characterization of lignins from maize stem and sugarcane bagasse

Sun

Wang

Zhang

et al. 2011

J of Applied Polymer Sci

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Lignins were isolated from maize stem and sugarcane bagasse by using mild dioxane or acidic dioxane solution. The result of nitrobenzene oxidation of the isolated lignins shows that there is a high proportion of phydroxyphenyl alcohol in the lignins of maize stem and sugarcane bagasse. The lignins isolated from maize stem and sugarcane bagasse have relatively same value of the weight-average (M w ¼ 3405-3868 g mol À1 ) and number-average (M n ¼ 1411-1612 g mol À1 ) molecular weights, and polydispersity (M w /M n ¼ 2.24-2.51). Acidic dioxane treatment did attack the b-aryl ether structures in lignins, in particular for b-aryl syringyl ethers, and broke the ester bonds between arabinose and ferulic acid that etherified to lignins, and it also cleaved lots of bonds in hemicellulosic polymer. The proportion of b-O-4 (threo) guaiacyl units is higher than that of b-O-4 (erthreo) guaiacyl units. The phenyl glycoside and benzyl ether linkages between lignin and hemicelluloses are also demonstrated in NMR analysis.

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Effect of ultrasound on the physicochemical properties of organosolv lignins from wheat straw

Cited by 27 publications

References 38 publications

Characteristics of Lignin from Flax Shives as Affected by Extraction Conditions

Characteristics of Lignin from Flax Shives as Affected by Extraction Conditions

Comparative Study of Crude and Purified Cellulose from Wheat Straw

Extraction and characterization of lignins from maize stem and sugarcane bagasse

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