Spruce Lignin Research Articles

On the Acid-catalysed Alkylation of Lignins

Acid-catalysed alkylation of spruce lignin and model compounds has been studied. Alkylation of veratrylglycerol-β-guaiacyl ether in a mixture of equimolar amounts of metanol, ethanol and 2,2,2-trifluoroethanol resulted in a preferential formation of methyl benzyl ether; the yield of ethyl ether was slightly lower while only trace amounts of the trifluoroethyl ether was formed. When 2,2,2-trifluoroethanol was used as reaction medium, condensation reactions occurred

Characterization of Lignins from Organosolv Pulping According to the Organocell Process. Part 4. Molecular Weight Determination and Investigation of Fractions Isolated by GPC

Abstract Soluble and residual spruce lignins were subjected to permanganate oxidation and thioacidolysis to elucidate changes in lignin's structure during Organocell pulping. As expected degradation reactions known from soda pulping are dominant especially in stage 2, including extensive enol ether formation. The chemical effect of methanol appears to be restricted to a minor methylation of the α-C-atom which prevents quinone methide formation and thus suppresses subsequent condensation reactions. Other beneficial effects of methanol such as liquor diffusion into the chips and a better lignin solubility obviously contribute to the successful delignification of softwoods in Organocell pulping.

Mineralization of the methoxyl carbon of isolated lignin by brown-rot fungi under solid substrate conditions

The objectives of this work were to begin developing an experimental system for studying the demethylation of lignin by brown-rot fungi and to examine the influence of selected culture parameters. As substrate for demethylation, we used partially 3-O-demethylated lignin that had been isolated earlier from brown-rotted spruce wood; we remethylated with14CH3I, giving a lignin with both [3-14C]methoxyl and [4-14C]methoxyl groups. This lignin was added to pine wood flakes, which were incubated with selected brown-rot fungi, and the evolved14CO2 was trapped and measured. Of eight fungi examined,Gloeophyllum trabeum andWolfiporia cocos gave the highest rates of mineralization of the14C-methoxyl carbons. With the former but not the latter fungus, methoxyl mineralization was over twice as fast in an atmosphere of O2 than in air. Amending the cultures with ammonium tartrate suppressed mineralization to some extent. Further studies withG. trabeum showed that glutamate lowered the rate of mineralization and that glucose and glycerol sharply suppressed it. Addition of Fe2+ and Mn2+ slightly increased the rate of mineralization. Our results suggest that in unsupplemented cultures the rate-limiting step in methoxyl mineralization is the initial demethylation. Thus the two likely initial C1 products, methanol and formaldehyde (as14C compounds), were mineralized much more rapidly than the methoxyl carbon of the lignin (as was formic acid), and no low molecular weight labeled intermediates from the [14C]-methoxyl lignin accumulated in the cultures. Our results also provide evidence that the spruce lignin was partially polymerized byG. trabeum. Mineralization of the methoxyl carbon of a synthetic [3-14C]-methoxyl lignin was slower than that of the spruce lignin, suggesting either that the synthetic lignin was more recalcitrant or that the [4-14C]methoxyl group in the [3,4-14C]-methoxyl spruce lignin was attacked more readily.

The Role of the Diarylpropane Structure as a Minor Constituent in Spruce Lignin

The amount of the diarylpropane type structure in spruce lignin was determined by the use of an ozonation method. Ozonation of both the diarylpropane and the phenylcoumaran type structures resulted in the formation of a dicarboxylic acid which possesses the original configurative structure of the side-chain. By determining yields and ratios of erythro and threo isomers of this dicarboxylic acid formed from model compounds and MWL, it was elucidated that the diarylpropane type structure can not be one of the major structures in spruce lignin

Lignins released from Picea abies suspension cultures—true native spruce lignins?

Suspension-cultured cells of Picea abies release lignin in the nutrient medium. Chemical analyses, 1H and 13C NMR spectroscopy of this material show that they represent carbohydrate-free guaiacyl type lignins with a high proportion of cinnamyl alcohol side chains a somewhat lower methoxyl content than milled wood lignin from spruce. The molecular weight distribution determined by HPSEC gave a weight average M r of 14 200 and a number average weight close to 4000. These are the first conifer lignin samples to be characterized without chemical or mechanical degradation.

Biomass electrochemistry: Anodic oxidation of an organo-solv lignin in the presence of nitroaromatics

The temperature required for the anodic conversion of an organo-solv spruce lignin, in aqueous alkaline solution, may be lowered by the addition of nitrobenzene or 1,3-dinitrobenzene. The additives cause significant and reproducible changes in the Tafel plot for the reaction. Preparativescale experiments are less reproducible although the range of phenolic products is generally similar to that produced by conventional nitrobenzene oxidation or by anodic oxidation at higher temperatures.

C—13 NMR Studies of a Dehydropolymer (DHP) from Isoeugenol; Comparison with Spruce Lignin

C—13 NMR Studies of a Dehydropolymer (DHP) from Isoeugenol; Comparison with Spruce Lignin

Biodegradation of Lignin in Spruce Wood byPhanerochaete chrysosporium:Quantitative Analysis of Biodegraded Spruce Lignins by13C NMR Spectroscopy

Article Biodegradation of Lignin in Spruce Wood by Phanerochaete chrysosporium: Quantitative Analysis of Biodegraded Spruce Lignins by 13C NMR Spectroscopy was published on January 1, 1989 in the journal Holzforschung (volume 43, issue 5).

Influence of Molecular Size and Ligninase Pretreatment on Degradation of Lignins by Xanthomonas sp. Strain 99

The purpose of this study was to examine the relationship between the molecular size of lignin in several preparations and extent of degradation (mineralization) by Xanthomonas sp. strain 99. The influence of ligninase pretreatment was also examined. Five synthetic lignins and one C-methylated spruce lignin were used. The extent of mineralization to CO(2) was greatest for the samples containing the most low-molecular-weight material, and the low-molecular-weight portions were preferentially (or perhaps solely) degraded. Pretreatment of the five synthetic lignins with crude ligninase increased their molecular size and decreased their degradability by the xanthomonad. Pretreatment of the methylated spruce lignin with crude ligninase caused both polymerization and depolymerization but resulted in a net decrease in bacterial degradability. Our results suggest that the xanthomonad can degrade lignins only up to a molecular weight of 600 to 1,000.

On the Occurrence of β-1 Structures in Lignins

Abstract 1H NMR spectral evidence for the occurrence of β-1 structures in lignins it presented. The number of β-1 side chains may be 1–2% in spruce lignin and perhaps as much as 5% in birch lignin.

Structural features of lignins and humic substances as revealed by spin-echo and broadband decoupled C-13 NMR spectroscopy

The C-13 NMR spectra of native aspen and native spruce lignin were used to interpret the spectra of Kraft lignins and selected humic substances. The nature and extent of side chain degradation, as well as changes in phenolic content, were clearly revealed in the Kraft lignin spectra. Evidence for residual lignin fragments was obvious in the spectra of the peat humic substances. Stream fulvic acid spectra revealed clear evidence of aromatic CH character. Soil fulvic acid, on the other hand, appeared to have a more highly condensed aromatic ring character than stream fulvic acid. The simplest spectrum was shown by the ground water fulvic acid.

Preparative Thioacidolysis of Spruce Lignin: Isolation and Identification of Main Monomeric Products

Structure des diastereoisomeres de type thioethylphenylpropane issus des thioacidolyses de lignine par chromatographie preparative combinee a la RMN et la spectroscopie de masse haute resolution

Effects of Cα -Oxidation in the Fungal Metabolism of Lignin

Abstract Cα-Oxidation (benzyl alcohol oxidation) is a prominent reaction in the degradation of lignin by white-rot fungi. This study showed that such oxidation markedly retards metabolism of a nonphenolic β-O-4 model compound, 1-(3-methoxy-4-ethoxyphenyl)-2-(o-methoxyphenoxy)propane-1,3-diol, by cultures of Phanerochaete chrysosporium Burds. Surprisingly, however, selective chemical Cα -oxidation of spruce lignins enhanced their depolymerization by the cultures. Thus the decrease in intrinsic degradability of substructures is more than compensated by another effect of Cα-oxidation in lignin. One possibility is that the oxidation increases the accessibility of the lignin to enzymes by decreasing its steric complexity. This study also revealed that the β-O-4 model, like lignin in wood, is degraded in part via Cα-oxidation by P. chrysosporium. Reduction of the α-carbonyl groups thus formed does not occur. Addition of L-glutamate to ligninolytic cultures completely suppresses their competence to degrade the m...

Pyrolysis-gas chromatography-mass spectrometry of isolated, synthetic and degraded lignins

Curie-point pyrolysis-gas chromatography-mass spectrometry was applied to study the chemical structure of sound and fungus degraded, industrial and synthetic lignins. Pyrolysis products reflected in some detail the structural units present in the lignin polymer. Thus, sound spruce lignin yielded trans-isoeugenol coniferaldehyde and trans-coniferyl alcohol as major pyrolysis products. Biodegraded lignin yielded oxidized units, including vanillin, acetoguaiacone, methyl vanillate, propioguaiacone, vanilloyl methyl ketone and vanillic acid as major products. Kraft lignin also showed evidence of oxidation, although not as much as the biodegraded lignin. Major products from this industrial lignin were guaiacol, methylguaiacol, vinylguaiacol and homovanillic acid. Results indicated that synthetic lignin duplicates fairly well the structure of natural lignin. However, coniferylaldehyde and trans-coniferyl alcohol were the dominant products only from the synthetic lignin, indicating the presence of large amounts of coniferyl alcohol and coniferylaldehyde end groups.

Decomposition of C-Labeled Maple and Spruce Lignin by Marine Fungi

Decomposition of C-Labeled Maple and Spruce Lignin by Marine Fungi

13C NMR Spectroscopic Study of Spruce Lignin DegradedPhanerochaete chrysosporium- II. Synthesis and Chemical Shifts of Model Compounds

Article 13C NMR Spectroscopic Study of Spruce Lignin Degraded Phanerochaete chrysosporium - II. Synthesis and Chemical Shifts of Model Compounds was published on January 1, 1982 in the journal Holzforschung (volume 36, issue 5).

Comparative studies in the ozonolysis of lignin and coal

The ozonizer used is illustrated and described. The experimental procedure for the ozonolysis of a spruce lignin sample and three bituminous coal samples in the temperature range 25–40°C is provided. The rate of reaction was found to vary between first and pseudo-zero order depending on the ozone concentration. (Supporting evidence was gained by paper chromatographic and potentiometric titrimetric studies of the reaction products.) A discussion on the structure of coal is given.

ChemInform Abstract: NMR STUDIES OF LIGNINS. 4. INVESTIGATION OF SPRUCE LIGNIN BY PROTON NMR SPECTROSCOPY

Chemischer InformationsdienstVolume 11, Issue 22 Natural Products ChemInform Abstract: NMR STUDIES OF LIGNINS. 4. INVESTIGATION OF SPRUCE LIGNIN BY PROTON NMR SPECTROSCOPY K. LUNDQUIST, K. LUNDQUISTSearch for more papers by this author K. LUNDQUIST, K. LUNDQUISTSearch for more papers by this author First published: June 3, 1980 https://doi.org/10.1002/chin.198022329AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume11, Issue22June 3, 1980 RelatedInformation

NMR Studies of Lignins. 4. Investigation of Spruce Lignin by 1H NMR Spectroscopy.

NMR Studies of Lignins. 4. Investigation of Spruce Lignin by 1H NMR Spectroscopy.

Organic geochemistry of silicified wood, Petrified Forest National Park, Arizona

Lignin derivatives have been isolated for the first time from carbonaceous sections of the silicified (~90% SiO 2) conifer Araucarioxylon arizonicum. The products released by sequential high vacuum pyrolysis and identified by combined gas chromatography-mass spectrometry (GC-MS) include a wide variety of alkyl-substituted, phenolic and condensed aromatic compounds. Brauns spruce lignin was pyrolized and analyzed by GC-MS as a comparison for the fossil wood data. The primary pyrolyzates at the 300°C step were CO 2, H 2O, ethanol and propanol. The main product at 450°C was 4-methyl-2-methoxyphenol (methyl guaiacol), but at 600°C the pyrolyzates were similar both in product composition and in relative abundance to those from silicified wood. The results suggest that the fossil wood experienced a mild thermal event during which the ether bonds were ruptured and loss of oxygen occurred along with the rearrangement of the original wood into a highly stable polymer.