Inhomogeneities in the Chemical Structure of Spruce Lignin

Holzforschung ◽  
2003 ◽  
Vol 57 (2) ◽  
pp. 165-170 ◽  
Author(s):  
H. Önnerud ◽  
G. Gellerstedt
Keyword(s):  
Chemical Structure ◽  
Kraft Pulp ◽  
Periodate Oxidation ◽  
Middle Lamella ◽  
Size Exclusion ◽  
Thermomechanical Pulp ◽  
Normal Wood ◽  
Mechanical Grinding ◽  
Spruce Wood ◽  
Exclusion Chromatography

Summary Thioacidolysis, periodate oxidation and size exclusion chromatography (SEC) were used for the analysis of spruce lignin samples. The standard thioacidolysis method was modified by including a pre-swelling of the lignocellulosic sample before the reaction, and this gave a higher yield of monomer products. Middle lamella and compression wood lignin was found to contain a larger amount of oligomers after thioacidolysis than normal wood lignin. Analysis by thioacidolysis of a thermomechanical pulp (TMP) revealed that approximately 10% of the β-O-4 structures in the lignin were cleaved due to the mechanical grinding effect. From kraft pulp, the mixture of thioacidolysis products contains a major fraction having a considerably larger molecular mass than the products from spruce wood and TMP. The structure of this material is still unknown.

Inhomogeneities in the Chemical Structure of Hardwood Lignins

Holzforschung ◽  
2003 ◽  
Vol 57 (3) ◽  
pp. 255-265 ◽  
Author(s):  
H. Önnerud ◽  
G. Gellerstedt
Keyword(s):  
Secondary Wall ◽  
Lignin Content ◽  
Middle Lamella ◽  
Size Exclusion ◽  
Wall Material ◽  
Thermomechanical Pulp ◽  
Aryl Ether ◽  
Spruce Wood ◽  
Exclusion Chromatography ◽  
The Difference

Summary Bauer-McNett fractions of an aspen chemi-thermomechanical pulp showed a significant variation with respect to lignin content and sugar composition, and two of the fractions were found to be particularly rich in middle lamella and secondary wall material, respectively. The secondary wall lignin of aspen was found to contain larger amounts of non-condensed β-O-4 aryl ether structures than the middle lamella lignin and the difference was attributed to a larger amount of syringyl structures as revealed by thioacidolysis. Size exclusion chromatography of the thioacidolysis products from birch and spruce wood showed a larger part of lignin oligomers being present in the degraded spruce lignin. Moreover, birch lignin had a lower phenolic content than both aspen and spruce lignin. Thioacidolysis followed by Raney-nickel desulphuration was used for the analysis of hardwood lignin trimers.

scholarly journals Chemical Structure–Antioxidant Activity Relationship of Water–Based Enzymatic Polymerized Rutin and Its Wound Healing Potential

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1566 ◽  
Author(s):  
Pivec ◽  
Kargl ◽  
Maver ◽  
Bračič ◽  
Elschner ◽  
...  
Keyword(s):  
Wound Healing ◽  
Chemical Structure ◽  
Water Solubility ◽  
Hacat Cell ◽  
Radical Scavenging ◽  
Water Soluble ◽  
Size Exclusion ◽  
Exclusion Chromatography ◽  
Relationship Of ◽  
Stable Free Radicals

The flavonoid rutin (RU) is a known antioxidant substance of plant origin. Its potential application in pharmaceutical and cosmetic fields is, however, limited, due to its low water solubility. This limitation can be overcome by polymerization of the phenolic RU into polyrutin (PR). In this work, an enzymatic polymerization of RU was performed in water, without the addition of organic solvents. Further, the chemical structure of PR was investigated using 1H NMR, and FTIR spectroscopy. Size-exclusion chromatography (SEC) was used to determine the molecular weight of PR, while its acid/base character was studied by potentiometric charge titrations. Additionally, this work investigated the antioxidant and free radical scavenging potential of PR with respect to its chemical structure, based on its ability to (i) scavenge non biological stable free radicals (ABTS), (ii) scavenge biologically important oxidants, such as O2•, NO•, and OH•, and (iii) chelate Fe2+. The influence of PR on fibroblast and HaCaT cell viability was evaluated to confirm the applicability of water soluble PR for wound healing application.

scholarly journals Partial Chemical Characterization of Immunomodulatory Polysaccharides from Plantago palmata Hook. f. s. Leaves

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Gabriel Biringanine ◽  
Moustapha Ouedraogo ◽  
Bernard Vray ◽  
Anne Berit Samuelsen ◽  
Pierre Duez
Keyword(s):  
Chemical Structure ◽  
Chemical Characterization ◽  
Biologically Active ◽  
Size Exclusion ◽  
Plantago Major ◽  
Activated Macrophages ◽  
Exclusion Chromatography ◽  
Very High ◽  
Partial Chemical

A previous work on Plantago palmata polysaccharides (PS) attributed immunomodulatory properties of leaves to a polysaccharide fraction (PS50) that stimulated NO and TNF-α production by interferon gamma- (IFN-γ-) activated macrophages. The present work aims to elucidate the chemical structure of these immunomodulatory polysaccharides. Size exclusion chromatography showed that the active polymers present an active fraction with a very high molecular weight (about 1200 kDa). These polysaccharides are pectic in nature, with a predominantly unbranched galacturonan domain and with a domain bearing side chains that consist of highly branched arabinan, galactan, and/or arabinogalactan. Comparatively to the well-known Plantago major biologically active PS, Plantago palmata PS50 contained less arabinogalactan-proteins (AGPs) and had a different composition in glucose, galactose, and galacturonic acid. DNA contamination of the polysaccharide was estimated at about 0.04%, a concentration much lower than those reported immunomodulatory in hyaluronic acid preparations (3 to 15%). Therefore, the eventuality of a contaminating DNA-mediated biological activity could be ruled out.

Size exclusion chromatographic and UV-VIS absorption analyses of unbleached and bleached softwood kraft pulps using LiCl/1,3-dimethyl-2-imidazolidinone as a solvent

Holzforschung ◽  
2007 ◽  
Vol 61 (3) ◽  
pp. 236-241 ◽  
Author(s):  
Masahiro Yanagisawa ◽  
Akira Isogai
Keyword(s):  
Kraft Pulp ◽  
Total Yield ◽  
Degree Of Polymerization ◽  
Size Exclusion ◽  
Kraft Pulps ◽  
Residual Lignin ◽  
Light Scattering Detection ◽  
Exclusion Chromatography ◽  
Photodiode Array ◽  
Sulfite Pulp

Abstract Unbleached and bleached kraft pulps and holocellulose prepared from softwood were totally soluble in 8% LiCl/1,3-dimethyl-2-imidazolidinone (LiCl/DMI). The solutions were analyzed by size exclusion chromatography with photodiode array and multi-angle laser light scattering detection (SEC-PDA-MALLS). The mobile phase consisted of 1% LiCl/DMI. The degree of polymerization (DP) and DP distribution of the softwood kraft pulps were determined, as well as the DP distribution of residual lignins based on their UV-VIS absorption patterns. Changes in DP for kraft pulps after a conventional bleaching sequence were evaluated, and the residual lignins were analyzed in the same way. Approximately half of the residual lignin in unbleached and bleached kraft pulps was present in polysaccharide fractions with high DP, which represented approximately 90% of the total yield. Some characteristic differences in the UV-VIS absorption pattern were observed between kraft pulps bleached with oxygen and chlorine. DP, DP distribution of polysaccharides, and distribution of residual lignin were clearly different for unbleached kraft pulp, unbleached sulfite pulp, and holocellulose. An unbleached kraft pulp prepared from hardwood showed different properties to the corresponding softwood preparation. The UV-VIS absorption patterns due to residual lignins were also very characteristic for the various pulps and holocellulose.

Modification of Spruce Lignans with Trametes hirsuta Laccase

Holzforschung ◽  
2002 ◽  
Vol 56 (6) ◽  
pp. 579-584 ◽  
Author(s):  
J. Buchert ◽  
A. Mustranta ◽  
T. Tamminen ◽  
P. Spetz ◽  
B. Holmbom
Keyword(s):  
Gas Chromatography ◽  
Size Exclusion Chromatography ◽  
Uv Spectroscopy ◽  
Size Exclusion ◽  
Trametes Hirsuta ◽  
Spruce Wood ◽  
Exclusion Chromatography

Summary The effect of Trametes hirsuta laccase on isolated spruce wood lignans was evaluated. Lignans were isolated from the heartwood of spruce branches and treated with different laccase dosages and treatment times. The effect of the treatment was monitored by gas chromatography, size exclusion chromatography and ionization difference UV spectroscopy. Lignans were efficiently oxidized by T. hirsuta laccase. About half of the phenolic groups present in lignans remained intact during the treatment. The oxidation of phenolic groups in lignans produced oligomeric structures containing approximately 4–5 lignan units (i.e., 8–10 phenyl propane units). Precipitation of the formed oligomeric structures probably prevented further polymerization.

scholarly journals Application of Monopotassium Dipropylene Glycoxide for Homopolymerization and Copolymerization of Monosubstituted Oxiranes: Characterization of Synthesized Macrodiols by MALDI-TOF Mass Spectrometry

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2795
Author(s):  
Zbigniew Grobelny ◽  
Justyna Jurek-Suliga ◽  
Sylwia Golba
Keyword(s):  
Chemical Structure ◽  
Normal Pressure ◽  
Size Exclusion ◽  
Complexing Agent ◽  
Thermoplastic Polyurethanes ◽  
Maldi Tof ◽  
Glycidyl Ethers ◽  
Exclusion Chromatography ◽  
Tetrahydrofuran Solution

Monopotassium dipropylene glycoxide, activated by a 18-crown-6 cation complexing agent (K-DPG/L, where DPG (dipropylene glycol) is a mixture of isomers) was used as an effective initiator of the homopolymerization and copolymerization of several monosubstituted oxiranes, i.e., propylene oxide (PO), 1.2-butylene oxide (BO), and some glycidyl ethers such as allyl, isopropyl, phenyl, and benzyl ones (AGE, IPGE, PGE, and BGE, respectively). The copolymers are novel and can be prospectively used for the fabrication of new thermoplastic or crosslinked polyurethanes. All processes were carried out in homogeneous mild conditions, i.e., tetrahydrofuran solution at room temperature and normal pressure. They resulted in new unimodal macrodiols with Mn = Mcalc in the range of 1500–8300, low dispersity Mw/Mn = 1.08–1.18 and a chemical structure well defined by several techniques, i.e., MALDI-TOF, size exclusion chromatography (SEC), 13C NMR, and FTIR. Monopotassium salts of homopolyether-diols, i.e., PPO-diol, PBO-diol, and PAGE-diol, appeared to be useful macroinitiators for the preparation of new triblock copolyether-diols by polymerization of glycidyl ethers. In BO/BGE random copolymerization initiated with K-DPG/L, macromolecules of copolyether-diol were exclusively formed. Macromolecules of copolyether-diol accompanied by homopolyether PPO-diol were identified in the PO/PGE system. However, AGE and PGE reacted by giving random copolyether-diol as well as homopolymer-diols, i.e., PAGE-diol and PPGE-diol. Macromolecules of prepared copolyether-diols contain various numbers of mers deriving from comonomers; the kind of comonomer determines the composition of the product. Several prepared homopolyether-diols and copolyether-diols could be useful for the synthesis of new thermoplastic polyurethanes.

scholarly journals Fragmentation of Chitosan by Acids

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammad Reza Kasaai ◽  
Joseph Arul ◽  
Gérard Charlet
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Kinetic Data ◽  
Chemical Structure ◽  
Size Exclusion ◽  
Experimental Conditions ◽  
First Order ◽  
H Nmr ◽  
Exclusion Chromatography ◽  
Kinetics Of

Fragmentation of chitosan in aqueous solution by hydrochloric acid was investigated. The kinetics of fragmentation, the number of chain scissions, and polydispersity of the fragments were followed by viscometry and size exclusion chromatography. The chemical structure and the degree of N-acetylation (DA) of the original chitosan and its fragments were examined by1H NMR spectroscopy and elemental analysis. The kinetic data indicates that the reaction was of first order. The results of polydispersity and the DA suggest that the selected experimental conditions (temperature and concentration of acid) were appropriate to obtain the fragments having the polydispersity and the DA similar to or slightly different from those of the original one. A procedure to estimate molecular weight of fragments as well as the number of chain scissions of the fragments under the experimental conditions was also proposed.

Lignin-carbohydrate network in wood and pulps: A determinant for reactivity

Holzforschung ◽  
2007 ◽  
Vol 61 (6) ◽  
pp. 668-674 ◽  
Author(s):  
Gunnar Henriksson ◽  
Martin Lawoko ◽  
Maria Eugenia Eugenio Martin ◽  
Göran Gellerstedt
Keyword(s):  
Kraft Pulp ◽  
Structural Changes ◽  
Aqueous Sodium Hydroxide ◽  
Complete Recovery ◽  
Size Exclusion ◽  
Sodium Borate ◽  
Precipitation Process ◽  
Analytical Technique ◽  
Chemical Pulp ◽  
Exclusion Chromatography

Abstract Pretreatment of wood or kraft pulp with endoglucanase followed by swelling in urea leaves a non-crystalline residue that can be dissolved in strong aqueous sodium hydroxide-sodium borate solution. A stepwise precipitation process employing acid and barium ions can separate lignin-carbohydrate complexes enriched in individual polysaccharides. This procedure has been applied to eucalypt and birch wood and to the corresponding kraft pulps. Thioacidolysis of the various lignin-carbohydrate complexes was used as the major analytical technique to obtain information about the structure and structural changes in lignin. A combination of thioacidolysis and size exclusion chromatography was used to obtain knowledge on the degree of depolymerisation and repolymerisation of lignin when going from wood to chemical pulp. In contrast to spruce wood and kraft pulp, complete recovery of the lignin-carbohydrate complexes could not be obtained from hardwood samples.

Isolation and structural elucidation of norlignan polymers from the heartwood of Cryptomeria japonica

Holzforschung ◽  
2015 ◽  
Vol 69 (3) ◽  
pp. 281-296 ◽  
Author(s):  
Yu Yanase ◽  
Kazuyuki Sakamoto ◽  
Takanori Imai
Keyword(s):  
Cryptomeria Japonica ◽  
High Performance ◽  
Chemical Structure ◽  
Size Exclusion ◽  
Spectrometric Data ◽  
Chemical Structures ◽  
Flight Mass Spectrometry ◽  
Exclusion Chromatography ◽  
Model Dimer ◽  
First Time

Abstract The norlignan (NorL) is a class of secondary metabolites, which occurs in the heartwood (hW) of certain softwood species. Although the NorL is often assumed to be secondarily altered (e.g., oxidized and/or polymerized in the hW over time), the formation and the chemical structure of oxidized/polymerized products remained unclear. In this study, we focused on the question whether an NorL oligomer/polymer exists in the hW of Cryptomeria japonica. First, NorL model polymers were prepared by horseradish peroxidase-catalyzed oxidation and their chemical structures were investigated by size exclusion chromatography-high-performance liquid chromatography (SEC-HPLC), nuclear magnetic resonance (NMR), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Second, methanol (MeOH) extracted from the hW of C. japonica was fractionated, and one of the fractions contained NorL polymers as demonstrated by its chromatographic and spectrometric data in comparison with those of model polymers. Third, five kinds of agatharesinol (AGA) model dimers were synthesized and their chemical structures were determined. 13C-NMR signals corresponding to the model dimer structures were observed in the NMR spectrum of the natural polymer fraction. In summary, an NorL polymer was found in the hW of C. japonica, and its preliminary chemical structure was proposed for the first time.

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