Photosensitized Delignification of Residual Lignin and Chemical Pulp from Eucalyptus grandis Wood

Holzforschung ◽  
2002 ◽  
Vol 56 (6) ◽  
pp. 595-600 ◽  
Author(s):  
D. Da Silva Perez ◽  
A. Castellan ◽  
A. Nourmamode ◽  
S. Grelier ◽  
R. Ruggiero ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Methylene Blue ◽  
Eucalyptus Grandis ◽  
Photochemical Reactions ◽  
Size Exclusion ◽  
Residual Lignin ◽  
Bleaching Process ◽  
Chemical Pulp ◽  
Exclusion Chromatography ◽  
Unbleached Pulp

Summary Bleached pulps were obtained from a Eucalyptus grandis peroxyformic/formic acid chemical pulp using oxygen, hydrogen peroxide, photosensitizers (methylene blue, Fe (II) 4,4′,4″,4‴-tetrasulfophthalocyanine, hemin, hematoporphyrin) and/or TiO2. Residual lignin of unbleached pulp, isolated and characterized by size exclusion chromatography, 31P NMR and thioacidolysis, was used to study the photochemical reactions occurring during the bleaching process. The main reactions were conversion of phenolic aromatic units into carboxylic acids and cleavage of the β-O-4 ether bonds leading to a depolymerization of the lignin framework into smaller fragments.

Behavior of xylans from the Eucalyptus species. Part 2. Characterization of 4-O-methylglucuronoxylans isolated from black liquors of kraft pulping of Eucalyptus grandis and E. urophylla

Holzforschung ◽  
2013 ◽  
Vol 67 (2) ◽  
pp. 123-128
Author(s):  
Andréia S. Magaton ◽  
Teresa Cristina F. Silva ◽  
Jorge Luiz Colodette ◽  
Dorila Piló-Veloso ◽  
Flaviana Reis Milagres ◽  
...  
Keyword(s):  
Average Molecular Weight ◽  
Eucalyptus Grandis ◽  
Kraft Pulping ◽  
Raw Material ◽  
Size Exclusion ◽  
Eucalyptus Species ◽  
Exclusion Chromatography ◽  
Ft Ir ◽  
Black Liquors

Abstract 4-O-methylglucuronoxylans isolated from Eucalyptus grandis and Eucalyptus urophylla kraft black liquors (KBLs) were chemically characterized by Fourier transform infrared spectroscopy (FT-IR), size exclusion chromatography (SEC), and nuclear magnetic resonance (NMR) spectroscopy. Doses of alkali charge, expressed as active alkali (AA), were 16, 17, and 18% while the sulfidity was kept at 25%. Kappa numbers of 19.1, 17.5, and 16.1 for E. grandis and 20.4, 16.8, and 15.4 for E. urophylla were obtained. At higher alkali charges, the recovery of xylans from the KBLs was lower and the degree of substitution of xylans with uronic acids decreased. The average molecular weight (Mw) of the recovered xylans was greater under conditions of mild pulping, i.e., in the case of pulps with higher kappa numbers. Mw of xylans ranged from 16.1 to 19.1 kDa for E. grandis and from 15.4 to 20.4 kDa for E. urophylla. The xylans from KBL may be useful as pulp modifying agents or as a raw material for advanced applications.

Hyphenated Size Exclusion Chromatography to Study Residual Lignin in Alkali Extracted Xylans from Paper Pulps

2017 ◽  
Vol 4 (1) ◽  
pp. 66-75
Author(s):  
Christian Hutterer ◽  
Gerhard Kliba ◽  
Karin Fackler ◽  
Stefan Bohmdorfer ◽  
Antje Potthast
Keyword(s):  
Size Exclusion Chromatography ◽  
Size Exclusion ◽  
Residual Lignin ◽  
Exclusion Chromatography ◽  
Paper Pulps

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.

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.

Decomposition of GFRP in Nitric Acid and Hydrogen Peroxide Solution for Chemical Recycling

2002 ◽  
Vol 18 (1) ◽  
pp. 49-68 ◽  
Author(s):  
Weirong Dang ◽  
Masatoshi Kubouchi ◽  
Takuya Maruyama ◽  
Hideki Sembokuya ◽  
Ken Tsuda
Keyword(s):  
Hydrogen Peroxide ◽  
Nitric Acid ◽  
Glass Fiber ◽  
Picric Acid ◽  
Hydrogen Peroxide Solution ◽  
Size Exclusion ◽  
Chemical Recycling ◽  
Chemical Structures ◽  
Glass Fiber Reinforced ◽  
Exclusion Chromatography

Decomposition of Glass Fiber Reinforced epoxy resin cured with amine in nitric acid and hydrogen peroxide solution has been investigated. After specimens were immersed in above solutions for a specific time, glass fiber could be separated from matrix resulting from the decomposition of matrix resin. The chemical structures and molecular weight distributions of the decomposed products were analyzed by FT-IR and size exclusion chromatography (SEC). When nitric acid was used, the resin was mainly decomposed into 2,4,6-trinitrophenol (picric acid) and quasi-monomer. In the case of hydrogen peroxide, the backbone of resin was broken into monomer and dimer, or peracetic acid, depending on immersion time. On the other hand, glass fiber exhibited low corrosion resistance to nitric acid, while it was hardly degraded in hydrogen peroxide. Based on analyzing the decomposed products and observing the degradation of glass fiber, the chemical recycling method on GFRP was proposed.

Isolation and characterization of lignins from Eucalyptus grandis Hill ex Maiden and Eucalyptus globulus Labill. by enzymatic mild acidolysis (EMAL)

Holzforschung ◽  
2008 ◽  
Vol 62 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Anderson Guerra ◽  
Lucian A. Lucia ◽  
Dimitris S. Argyropoulos
Keyword(s):  
Eucalyptus Globulus ◽  
Eucalyptus Grandis ◽  
Raw Material ◽  
Size Exclusion ◽  
Hydroxyl Groups ◽  
Aryl Ether ◽  
Isolation And Characterization ◽  
White Fir ◽  
Exclusion Chromatography

Abstract Despite the growing importance of Eucalyptus wood as raw material for pulp and paper, there is a lack of knowledge on the chemistry of their macromolecular components. The present paper addresses this issue by applying the recently developed protocol for isolating enzymatic mild acidolysis lignins (EMAL) from Eucalyptus grandis, Eucalyptus globulus and the softwood species Douglas fir and white fir, which were used for comparative purposes. The structures of EMALs were investigated by quantitative 31P NMR, DFRC/31P NMR (derivatization followed by reductive cleavage followed by quantitative 31P NMR) and size exclusion chromatography (SEC). Overall, the yields of EMALs isolated from Eucalyptus were higher than those from the softwoods examined. Lignin from E. globulus was found to contain higher contents of arylglycerol-β-aryl ether structures, free phenolic hydroxyl groups and syringyl-type units than lignin from E. grandis. New insights provided by the DFRC/31P NMR revealed that up to 62.2% of arylglycerol-β-aryl ether structures in E. globulus are uncondensed, while in E. grandis the amount of such uncondensed structures was found to be lower than 48%. SEC analyses showed that lignins from E. grandis and softwoods associate in greater extension than lignin from E. globulus.

CHARACTERIZATION OF A NEW LCAT MUTATION CAUSING FAMILIAL LCAT DEFICIENCY (FLD) AND THE ROLE OF APOE AS A MODIFIER GENE OF THE FLD PHENOTYPE

2009 ◽  
Vol 32 (6S) ◽  
pp. 3
Author(s):  
A Baass ◽  
H Wassef ◽  
M Tremblay ◽  
L Bernier ◽  
R Dufour ◽  
...  
Keyword(s):  
Modifier Gene ◽  
Size Exclusion ◽  
Plasma Lipoproteins ◽  
Lipoprotein Profile ◽  
Exclusion Chromatography ◽  
Low Hdl ◽  
Lcat Deficiency ◽  
Apoe Genotypes

Introduction: LCAT (lecithin:cholesterol acyltransferase ) is an enzyme which plays an essential role in cholesterol esterification and reverse cholesterol transport. Familial LCAT deficiency (FLD) is a disease characterized by a defect in LCAT resulting in extremely low HDL-C, premature corneal opacities, anemia as well as proteinuria and renal failure. Method: We have identified two brothers presenting characteristics of familial LCAT deficiency. We sequenced the LCAT gene, measured the lipid profile as well as the LCAT activity in 15 members of this kindred. We also characterized the plasma lipoproteins by agarose gel electrophoresis and size exclusion chromatography and sequenced several candidate genes related to dysbetalipoproteinemia in this family. Results: We have identified the first French Canadian kindred with familial LCAT deficiency. Two brothers affected by FLD, were homozygous for a novel LCAT mutation. This c.102delG mutation occurs at the codon for His35 causing a frameshift that stops transcription at codon 61 abolishing LCAT enzymatic activity both in vivo and in vitro. It has a dramatic effect on the lipoprotein profile, with an important reduction of HDL-C in both heterozygotes (22%) and homozygotes (88%) and a significant decrease in LDL-C in heterozygotes (35%) as well as homozygotes (58%). Furthermore, the lipoprotein profile differed markedly between the two affected brothers who had different APOE genotypes. We propose that APOE could be an important modifier gene explaining heterogeneity in lipoprotein profiles observed among FLD patients. Our results suggest that a LCAT-/- genotype associated with an APOE ?2 allele could be a novel mechanism leading to dysbetalipoproteinemia.

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