Fractional isolation and physico-chemical characterization of alkali-soluble lignins from fast-growing poplar wood

Sun, Run‐Cang; Tomkinson, J.; Sun, Xiaofang; Wang, N.J

doi:10.1016/s0032-3861(00)00190-7

Cited by 52 publications

(27 citation statements)

References 18 publications

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“…Before each experiment, the raw material was dried and ground into coarse powder approximately 0.15-0.18 mm in size. The isolation of AL was based on the method proposed by Sun et al (2000), where the NaOH concentration was 5% and the process was performed at 50°C for 6 h. KL was obtained from the acid-insoluble fraction by NREL standard procedures (Sluiter et al, 2008). In the method previously described by Pan et al (2006), OL was extracted by adding a small amount of sulfuric acid (1.2 wt% of raw biomass) to a mixed solution of ethanol and water (65:35, v/v) at 170°C for 80 min.…”

Section: Methodsmentioning

confidence: 99%

Pyrolysis behaviors of four lignin polymers isolated from the same pine wood

Wang

Lin

et al. 2015

Bioresource Technology

311

132

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Section: Methodsmentioning

confidence: 99%

Pyrolysis behaviors of four lignin polymers isolated from the same pine wood

Wang

Lin

et al. 2015

Bioresource Technology

311

132

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“…This suggests that the non-conjugated phenolic groups and the conjugated phenolic groups of LW and LL were not substituted by the oxygen-containing groups in lignin, and were slightly damaged. At the same time, the much lower absorption at 320 nm LS, LE, and LB revealed that the conditions given substantially cleaved the ester or ether bonds between p-coumaric acid and ferulic acid, and lignin during ethanol pretreatments (Sun et al 2000). This finding also echoed the variation observed in the weak bands in the FT-IR spectra at 1708 and 1654 cm −1 , which were associated with the non-conjugated and conjugated carbonyl/carboxyl stretching, respectively.…”

Section: Ft-ir and Uv Spectra Analysismentioning

confidence: 67%

“…Strong absorption peaks were observed between 1600 and 1508 cm −1 derived from the skeletal and stretching vibrations of the benzene rings. The peak multiplicity at 1267 cm −1 is a representative signal of the p-hydroxyphenyl structures of herbage lignin (Sun et al 2000).…”

Section: Ft-ir and Uv Spectra Analysismentioning

confidence: 99%

Structural Changes of Lignin from Wheat Straw by Steam Explosion and Ethanol Pretreatments

et al. 2016

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Effects of the pretreatment of wheat straw by steam explosion and ethanol were evaluated relative to the structural changes of lignin from the pretreated pulp. The lignin from steam explosion pulp (LS), lignin from steam blasting residual liquid (LL), lignin from ethanol pretreatment pulp (LE), lignin from black liquor (LB), and lignin from wheat straw (LW) were separated, and the structural characteristics of the lignin fractions were compared based on analyses of Fourier transform-infrared, ultraviolet, thermogravimetric, and 1 H and 13 C nuclear magnetic resonance spectra. The proportions of the three structural units in all lignin fractions clearly changed during the pretreatment process because of inter-conversion reactions. The conjugated structure of lignin was destroyed in the pretreatment process and was also affected by the alkali extraction process. The alcoholic hydroxyl links on the aliphatic side chain were partly transformed into carbonyl groups during ethanol pretreatment. Demethoxylation occurred in all lignin fractions during the ethanol pretreatment and steam explosion process. The thermal stability of the LB fraction was relatively high because of the condensation reaction.

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“…Absorbances at 200 to 500 nm of the extracts obtained using the subcritical 50% and 75% (v/v) ethanol/water mixtures were higher than that obtained using subcritical ethanol. The absorbance at 280 nm suggests the presence of phenolic compounds, which may be derived from lignin (Morrison, 1971;Sun et al, 2010). The lower absorbance around 250 nm indicates non-lignin materials, such as the decomposition products of carbohydrates and other extractives (Xiao et al, 2001).…”

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confidence: 99%

Properties of Rice Stem Extracts Obtained by Subcritical Water/Ethanol Treatment

Tangkhavanich

Oishi

Kobayashi

et al. 2013

FSTR

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Rice straw stem was treated with subcritical water, ethanol, or a mixture at 170℃ to 230℃. The yield, total carbohydrate content, UV-Vis absorption spectra, phenolic content, radical scavenging activity, and HPLC analysis of the extracts were determined. Higher stem extract yield and total carbohydrate content were achieved when the stem was treated using a subcritical ethanol/water mixture with high ethanol content and at the higher temperature. A maximum yield and total carbohydrate content of 0.387 ± 0.004 g/g-stem and 0.219 ± 0.021 g/g-stem, respectively, were achieved when the stem was treated with 50% (v/ v) ethanol at 230℃. The extract obtained using 75% (v/v) ethanol at 230℃ had the highest total phenolic content and radical scavenging activity of 45.2 ± 1.1 mg-gallic acid equiv./g-stem and 0.308 ± 0.022 mmolvitamin C equiv./g-stem, respectively.Keywords: extraction, radical scavenging, rice straw, subcritical fluid *To whom correspondence should be addressed. E-mail: adachi@kais.kyoto-u.ac.jp IntroductionRice straw is very abundant and is considered an agricultural waste (Dominguez-Escriba and Parcar, 2010;Kadam et al., 2000). Many applications of rice straw have been investigated; however, the amount of rice straw utilized remains very low compared to the worldwide annual production. The three major components of rice straw are cellulose, hemicellulose, and lignin, which are considered to contain promising substances (Lawther et al., 1996). Due to the hydrogen bonds between the glucose molecules of cellulose and the covalent bonds in lignin, rice stem is only slightly soluble in water at ambient temperature (Xiao et al., 2001). At high temperatures (100℃ to 374℃), water can maintain its liquid state under pressurized conditions, and is called subcritical water or compressed hot water. The ion product of subcritical water increases to over 1 × 10 3 fold greater than that of water at room temperature (Marshall and Franck, 1981;Wagner and Pruß, 2002). Due to high concentrations of hydroxium and hydroperoxide ions, subcritical water has the ability to hydrolyze hemicellulose, lignin, and the amorphous part of cellulose. Another feature is its low dielectric constant, which can be adjusted by controlling the temperature. The dielectric constant of water decreases from 80 at ambient temperature to 27 at 250℃. The dielectric constant of subcritical water matches that of ethanol or acetone at room temperature. With these features, water under subcritical conditions can liberate phenolic compounds, which are bonded to the carbohydrate backbone (Bobleter, 1994;Kumar et al., 2010). Chiou et al. (2012) reported that a subcritical water/ethanol mixture could more effectively extract protein, carbohydrate, and phenolic compounds from defatted rice bran than subcritical water or ethanol alone. The addition of ethanol enhances extraction efficiency because constituents with different polarities in the extract are obtained by the ethanol and water (Durling et al., 2007;Richter et al., 1996). Other advantages of ethanol...

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Fractional isolation and physico-chemical characterization of alkali-soluble lignins from fast-growing poplar wood

Cited by 52 publications

References 18 publications

Pyrolysis behaviors of four lignin polymers isolated from the same pine wood

Pyrolysis behaviors of four lignin polymers isolated from the same pine wood

Structural Changes of Lignin from Wheat Straw by Steam Explosion and Ethanol Pretreatments

Properties of Rice Stem Extracts Obtained by Subcritical Water/Ethanol Treatment

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