Quantitative<sup>13</sup>C NMR Characterization of Milled Wood Lignins Isolated by Different Milling Techniques

Holtman, Kevin M.; Chang, Hou‐min; Jameel, Hasan; Kadla, John F.

doi:10.1080/02773810600582152

Cited by 174 publications

(143 citation statements)

References 12 publications

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“…The remaining wide peak associated with the acetyl methyl group of cellulose at 0-40 ppm suggested that alkyl carbon was still present. The small peaks associated with lignin and the methoxyl groups of lignin at approximately 140 and 56 ppm (Holtman et al, 2006;Park et al, 2013), respectively, were also more distinguishable after carbonization at 260 °C for 5 h most likely due to the decomposition of carbohydrates. The relatively low increase in the intensity of aromatic peaks indicated that sludge carbonization was mainly governed by dehydration, depolymerization and decarboxylation rather than polymerization and aromatization of sludge components.…”

Section: Chemical Structure Of Sludge and Hydrocharmentioning

confidence: 98%

“…In addition, a minor signal at approximately 85 ppm indicated the presence of C-4 carbons and a wellresolved peak at 105 ppm the anomeric C-1 carbon of sugars (Bardet et al, 1986;Wikberg and Maunu, 2004). No noticeable peaks were found with untreated sludge within 120-160 ppm which are generally characteristic for sp2 carbon atoms in the C=C double and O-C=C oxygen bonds (Holtman et al, 2006). Nor did the spectra support the presence of C=O groups in either carboxylic acids (170-200 ppm) or ketones and aldehydes (200-220 ppm) of hemicellulose.…”

Section: Chemical Structure Of Sludge and Hydrocharmentioning

confidence: 99%

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Hydrothermal carbonization of industrial mixed sludge from a pulp and paper mill

Mäkelä

Benavente

Fullana

2016

Bioresource Technology

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Please cite this article as: Mäkelä, M., Benavente, V., Fullana, A., Hydrothermal carbonization of industrial mixed sludge from a pulp and paper mill, Bioresource Technology (2015), doi: http://dx.doi.org/10.1016/j.biortech. 2015.10.062 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractMixed sludge from a pulp and paper mill was hydrothermally carbonized at 180-260 °C for 0.5-5 h with the use of HCl or NaOH for determining the effect of acid and base additions during sludge carbonization. Based on the results carbonization was mainly governed by dehydration, depolymerization and decarboxylation of sludge components.Additive type had a statistically significant effect on hydrochar carbon content and carbon and energy yield, of which especially energy yield increased through the use of HCl. The theoretical energy efficiencies of carbonization increased with decreasing reaction temperature, retention time and the use of HCl and suggested that the energy requirement could be covered by the energy content of attained hydrochar. The BOD 5 /COD -ratios of analyzed liquid samples indicated that the dissolved organic components could be treated by conventional biological methods.

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Section: Chemical Structure Of Sludge and Hydrocharmentioning

confidence: 98%

Section: Chemical Structure Of Sludge and Hydrocharmentioning

confidence: 99%

Hydrothermal carbonization of industrial mixed sludge from a pulp and paper mill

Mäkelä

Benavente

Fullana

2016

Bioresource Technology

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“…The lignin samples (2 mg) without acetylation were dissolved in 4 mL of tetrahydrofuran (THF), and 20 μL lignin solutions were injected. The solution-state NMR spectra of the lignin samples were acquired on a 400 MHz NMR spectrometer (AVIII 400, Bruker, Karlsruhe, Germany) at 25 °C using 140 mg of lignin in 0.5 mL of DMSO-d6 for 13 C NMR spectra and 40 mg of lignin in 0.5 mL of DMSO-d6 for HSQC NMR spectra (Holtman et al 2006;Rencoret et al 2008).…”

Section: Analysis Proceduresmentioning

confidence: 99%

Structural Characterization of Lignin Isolated from Wheat-Straw during the Alkali Cooking Process

Tian

Wang

et al. 2017

BioResources

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aTo investigate the behavior of lignin during the alkali cooking process with different alkali doses, this work demonstrated the structural characteristics illustrated by spectroscopic analyses. Gel permutation chromatography (GPC) and nuclear magnetic resonance (NMR) indicated that the lignin was composed of typical structures for a grass, generally with S and G units and small amounts of H units. The main substructures present were β-O-4 aryl ether linkages, and there were lower amounts of β-β and β-5 linkages. Alkali treatment conditions had evident effects on the chemical structures and properties of lignin. Moreover, NMR indicated that alkali cooking caused lignin to depolymerize more easily with increasing severity and to condense.

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“…The peak assignments of lignin were based on previous literature (Lin and Dence 1992;Holtman et al 2006). In the 13 C-NMR spectra of RL and ILL, the characteristic tertiary carbon resonances from syringylpropane (S) (signals centered at 104.9 ppm) and guaiacylpropane (G) units (signals centered at 111.5 ppm and 119.3 ppm) were observed.…”

Section: Nuclear Magnetic Resonance Spectroscopymentioning

confidence: 99%

Structural Changes of Lignin after Ionic Liquid Pretreatment

et al. 2017

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Changes of lignin's structure were investigated resulting from an ionic liquid ([Bmim]Cl,1-butyl-3-methylimidazolium chloride salt) pretreatment. The purified lignin was pretreated by [Bmim]Cl under the following conditions: the ionic liquid to lignin mass ratio was 10:1, the temperature was 85 °C, and the processing time was 2 h and 4 h. The chemical structure of lignin was studied via Ultraviolet (UV) spectra, Fourier Transform infrared (FT-IR) spectra, Nuclear Magnetic Resonance Spectroscopy ( 13 C-NMR), Gel Permeation Chromatography (GPC), X-ray photoelectron spectroscopy (XPS), and Thermogravimetric Analysis (TG). The total content of phenolic hydroxyl increased with increased time. Moreover, the contents of [OHI] and [OHII] (types of phenolic hydroxyl groups) groups were disproportionately increased. The main structure of lignin still was present after the [Bmim]Cl pretreatment. The β-O-4 linkages were broken apart. The degree of lignin degeneration increased with increased time, after being pre-treated with [Bmim]Cl. Simultaneously, a condensation reaction also took place during the pretreatment. Understanding the chemical changes to wheat straw lignin during an ionic liquid pretreatment provides an important theoretical basis for its further industrial use.

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Quantitative¹³C NMR Characterization of Milled Wood Lignins Isolated by Different Milling Techniques

Cited by 174 publications

References 12 publications

Hydrothermal carbonization of industrial mixed sludge from a pulp and paper mill

Hydrothermal carbonization of industrial mixed sludge from a pulp and paper mill

Structural Characterization of Lignin Isolated from Wheat-Straw during the Alkali Cooking Process

Structural Changes of Lignin after Ionic Liquid Pretreatment

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Quantitative13C NMR Characterization of Milled Wood Lignins Isolated by Different Milling Techniques

Cited by 174 publications

References 12 publications

Hydrothermal carbonization of industrial mixed sludge from a pulp and paper mill

Hydrothermal carbonization of industrial mixed sludge from a pulp and paper mill

Structural Characterization of Lignin Isolated from Wheat-Straw during the Alkali Cooking Process

Structural Changes of Lignin after Ionic Liquid Pretreatment

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Product

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Quantitative¹³C NMR Characterization of Milled Wood Lignins Isolated by Different Milling Techniques