Characterization of non-cellulosic glucans in Eucalyptus globulus Labill. wood and kraft pulp

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 478-482 ◽  
Author(s):  
Sara A. Lisboa ◽  
Dmitry V. Evtuguin ◽  
Carlos Pascoal Neto
Keyword(s):  
Eucalyptus Globulus ◽  
Fiber Surface ◽  
2D Nmr ◽  
Structural Features ◽  
Kraft Pulping ◽  
Hot Water ◽  
Pulp Yield ◽  
Naoh Solution ◽  
Nmr Techniques

Abstract The amount of non-cellulosic glucans in Eucalyptus globulus wood (approx. 4.5%) was assessed by extraction of sawdust with a 0.5 M NaOH solution at 90–120°C and the structural features were elucidated in a glucan-enriched polysaccharide fraction isolated by hot water extraction (120°C, 2 h). Isolated soluble glucans were characterized by wet chemistry methods and a set of 1D and 2D NMR techniques. The major proportion of glucans consisted of amylose (20%) and amylopectin (80%), although a small proportion of β-(1→3)-glucan (<0.2% on wood weight) was also detected. Although glucans are easily removed in the initial phase of kraft pulping, notable amounts were found in unbleached pulp and it was supposed that in the final stage of kraft pulping a fraction of α-glucan is precipitated onto the fiber surface and contributes to the pulp yield.

Polysulfide-borohydride modification of southern pine alkaline pulping integrated with hydrothermal pre-extraction of hemicelluloses

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 9-16
Author(s):  
SUNG-HOON YOON ◽  
HARRY CULLINAN ◽  
GOPAL A. KRISHNAGOPALAN
Keyword(s):  
Loblolly Pine ◽  
Sodium Borohydride ◽  
Kraft Pulping ◽  
Hot Water ◽  
Pulp Yield ◽  
Paper Strength ◽  
Southern Pine ◽  
Two Stage ◽  
Simultaneous Treatment ◽  
Process Modification

We studied three process modifications to investigate their effects on the property and yield recovery capabilities of kraft pulping integrated with hemicellulose pre-extraction of southern pine. Loblolly pine chips were pre-extracted with hot water until the sugar extraction yield reached the targeted value of 10% and then subjected to conventional and modified kraft pulping. Modification included polysulfide pretreatment; polysulfide-sodium borohydride dual pretreatment, and polysulfide followed by polysulfide-sodium borohydride dual pretreatment two-stage pretreatments prior to kraft pulping. In the first modification, about 5% of the lost pulp yield (total 7%) caused by hemicellulose pre-extraction could be recovered with 15%-20% polysulfide pretreatment. Complete recovery (7%) was achieved with simultaneous pretreatment using 15% polysulfide and 0.5% sodium borohydride with 0.1% anthraquinone in polysulfide-sodium borohydride dual pretreatment. Two-stage pretreatment using recycled 15% polysulfide followed by simultaneous treatment of 6% polysulfide and 0.4%–0.5% sodium borohydride with 0.1% anthraquinone also achieved 100% yield recovery. Continuous recycling of 15% polysulfide employed in the two-stage process modification maintained its yield protection efficiency in a repeated recycling cycle. No significant changes in paper strength were found in handsheets prepared from the three process modifications, except for a minor reduction in tear strength.

scholarly journals Chemical characteristics and Kraft pulping of tension wood from Eucalyptus globulus labill

2012 ◽  
Vol 36 (6) ◽  
pp. 1163-1172 ◽  
Author(s):  
María Graciela Aguayo ◽  
Regis Teixeira Mendonça ◽  
Paulina Martínez ◽  
Jaime Rodríguez ◽  
Miguel Pereira
Keyword(s):  
Eucalyptus Globulus ◽  
Lignin Content ◽  
Strength Properties ◽  
Kraft Pulping ◽  
Pulp Yield ◽  
Chemical Characteristics ◽  
Kraft Pulps ◽  
Opposite Wood ◽  
Alkali Consumption ◽  
Pulp Strength

Tension (TW) and opposite wood (OW) of Eucalyptus globulus trees were analyzed for its chemical characteristics and Kraft pulp production. Lignin content was 16% lower and contained 32% more syringyl units in TW than in OW. The increase in syringyl units favoured the formation of β-O-4 bonds that was also higher in TW than in OW (84% vs. 64%, respectively). The effect of these wood features was evaluated in the production of Kraft pulps from both types of wood. At kappa number 16, Kraft pulps obtained from TW demanded less active alkali in delignification and presented slightly higher or similar pulp yield than pulps made with OW. Fiber length, coarseness and intrinsic viscosity were also higher in tension than in opposite pulps. When pulps where refined to 30°SR, TW pulps needed 18% more revolutions in the PFI mill to achieve the same beating degree than OW pulps. Strength properties (tensile, tear and burst indexes) were slightly higher or similar in tension as compared with opposite wood pulps. After an OD0(EO)D1 bleaching sequence, both pulps achieved up to 89% ISO brightness. Bleached pulps from TW presented higher viscosity and low amount of hexenuronic acids than pulps from OW. Results showed that TW presented high xylans and low lignin content that caused a decrease in alkali consumption, increase pulp strength properties and similar bleaching performance as compared with pulps from OW.

Structural characterization of milled wood lignins from different eucalypt species

Holzforschung ◽  
2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Jorge Rencoret ◽  
Gisela Marques ◽  
Ana Gutiérrez ◽  
David Ibarra ◽  
Jiebing Li ◽  
...  
Keyword(s):  
Eucalyptus Globulus ◽  
Chemical Structure ◽  
2D Nmr ◽  
Analytical Pyrolysis ◽  
Additional Information ◽  
Diaryl Ether ◽  
Heteronuclear Single Quantum Correlation ◽  
Relative Abundances ◽  
Type 3

Abstract The chemical structure of milled-wood lignins from Eucalyptus globulus, E. nitens, E. maidenii, E. grandis, and E. dunnii was investigated. The lignins were characterized by analytical pyrolysis, thioacidolysis, and 2D-NMR that confirmed the predominance of syringyl over guaiacyl units and only showed traces of p-hydroxyphenyl units. E. globulus lignin had the highest syringyl content. The heteronuclear single quantum correlation (HSQC) NMR spectra yielded information about relative abundances of inter-unit linkages in the whole polymer. All the lignins showed a predominance of β-O-4′ ether linkages (66–72% of total side-chains), followed by β-β′ resinol-type linkages (16–19%) and lower amounts of β-5′ phenylcoumaran-type (3–7%) and β-1′ spirodienone-type linkages (1–4%). The analysis of desulfurated thioacidolysis dimers provided additional information on the relative abundances of the various carbon-carbon and diaryl ether bonds, and the type of units (syringyl or guaiacyl) involved in each of the above linkage types. Interestingly, 93–94% of the total β-β′ dimers included two syringyl units indicating that most of the β-β′ substructures identified in the HSQC spectra were of the syringaresinol type. Moreover, three isomers of a major trimeric compound were found which were tentatively identified as arising from a β-β′ syringaresinol substructure attached to a guaiacyl unit through a 4-O-5′ linkage.

scholarly journals Synthesis and Characterization of Low-Cost Cresol-Based Benzoxazine Resins as Potential Binders in Abrasive Composites

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2995
Author(s):  
Artur Jamrozik ◽  
Mateusz Barczewski ◽  
Grzegorz Framski ◽  
Daniel Baranowski ◽  
Paulina Jakubowska ◽  
...  
Keyword(s):  
Low Cost ◽  
2D Nmr ◽  
Additional Analysis ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Voc Emission ◽  
Chemical Structures ◽  
Oxazine Ring ◽  
Nmr Techniques

A series of cresol-based benzoxazines were synthesized for potential application as a polymer matrix in abrasive composites. The chemical structures of the obtained benzoxazine resins were investigated in detail using Fourier transform infrared spectroscopy (FTIR) and hydrogen-1 as well as carbon-13 nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR) with an additional analysis using two-dimensional NMR techniques (2D NMR 1H-1H COSY, 1H-13C gHSQC and gHMBC). Structural analysis confirmed the presence of vibrations of -O-C-N- at ~950 cm−1 wavenumber, characteristic for an oxazine ring. The thermal properties of benzoxazine monomers were examined using differential scanning calorimetry (DSC) analysis. The polymerization enthalpy varied from 143.2 J/g to 287.8 J/g. Thermal stability of cresol-based benzoxazines was determined using thermogravimetry (TGA) analysis with additional analysis of the amount of volatile organic compounds (VOC) emitted from the synthesized benzoxazines during their crosslinking by static headspace coupled with gas chromatography technique (HS-GC). The amount of residual mass significantly differed between all synthesized polybenzoxazines in the range from 8.4% to 21.2%. The total VOC emission for benzoxazines decreased by 46–77% in reference to a conventional phenolic binder. The efficiency of abrasive composites with the benzoxazine matrix was evaluated based on abrasion tests. Performed analyses confirmed successful synthesis and proper chemical structure of cresol-based benzoxazines. All the experiments indicated that benzoxazines based on different cresol isomers significantly differ from each other. Good thermal performance and stability of the abrasive composites with the polybenzoxazine matrix and significantly lower VOC emission allow us to state that benzoxazines can be a promising and valuable alternative to the phenolics and a new path for the development of modern, eco-friendly abrasives.

Characterization of Lignin-Carbohydrate Fractions Isolated from the Wood Parasite Cistance deserticola Y.C. Ma

Holzforschung ◽  
1999 ◽  
Vol 53 (1) ◽  
pp. 33-38 ◽  
Author(s):  
B. Kosiková ◽  
A. Ebringerová ◽  
R. Naran
Keyword(s):  
Chemical Analysis ◽  
Hot Water ◽  
Klason Lignin ◽  
Sequential Extractions ◽  
Pectic Polysaccharides ◽  
Sugar Analysis ◽  
Cistanche Deserticola ◽  
Naoh Solution

Summary Chemical analysis of Cistanche deserticola showed the presence of 7.5% of Klason lignin. Different lignin-carbohydrate fractions have been isolated from the methanol pre-extracted and depectinated Cistanche drug by sequential extractions using dioxane-water, cold and hot water, and 4% NaOH solution. 13CNMR spectroscopy in combination with sugar analysis were used to characterize the isolated fractions. The proportions of the guaiacyl-, syringyl- and p-hydroxyphenyl units in the lignin-rich fractions differ significantly from those of both hardwood and softwood lignins and resemble more those of gramineous lignins. The carbohydrate portion consists of xylan, starch, pectic polysaccharides, and cellulose in proportions which are not typical of wood tissues.

scholarly journals Isolation and Characterization of Two New Antimicrobial Acids from Quercus incana (Bluejack Oak)

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Rizwana Sarwar ◽  
Umar Farooq ◽  
Sadia Naz ◽  
Nadia Riaz ◽  
Syed Majid Bukhari ◽  
...  
Keyword(s):  
Ethyl Acetate Fraction ◽  
Structural Formula ◽  
2D Nmr ◽  
Spectroscopic Technique ◽  
Pentanoic Acid ◽  
One Dimensional ◽  
Isolation And Characterization ◽  
Nmr Techniques ◽  
New Compounds

Two new compounds [1-2] were purified from ethyl acetate fraction of Quercus incana. The structure of these compounds is mainly established by using advanced spectroscopic technique such as UV, IR, one-dimensional (ID) and two-dimensional (2D) NMR techniques, and EI mass. The structural formula was deduced to be 4-hydroxydecanoic acid [1] and 4-hydroxy-3-(hydroxymethyl) pentanoic acid [2]. Both isolated compounds were tested for their antimicrobial potential and showed promising antifungal activity against Aspergillus niger and Aspergillus flavus.

scholarly journals Versatile1H−31P−31P COSY 2D NMR Techniques for the Characterization of Polyphosphorylated Small Molecules

2010 ◽  
Vol 75 (10) ◽  
pp. 3214-3223 ◽  
Author(s):  
Ananya Majumdar ◽  
Yan Sun ◽  
Meha Shah ◽  
Caren L. Freel Meyers
Keyword(s):  
Small Molecules ◽  
2D Nmr ◽  
Nmr Techniques

scholarly journals HSQC-NMR analysis of lignin in woody (Eucalyptus globulus and Picea abies) and non-woody (Agave sisalana) ball-milled plant materials at the gel state 10th EWLP, Stockholm, Sweden, August 25–28, 2008

Holzforschung ◽  
2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Jorge Rencoret ◽  
Gisela Marques ◽  
Ana Gutiérrez ◽  
Lidia Nieto ◽  
J. Ignacio Santos ◽  
...  
Keyword(s):  
Picea Abies ◽  
Eucalyptus Globulus ◽  
2D Nmr ◽  
Structural Features ◽  
Rapid Screening ◽  
Nmr Analysis ◽  
Plant Materials ◽  
General Terms ◽  
Whole Plant ◽  
Agave Sisalana

Abstract In situ analysis of lignin by 2D NMR of whole plant material was carried out by swelling finely ball-milled samples in deuterated dimethylsulfoxide (DMSO-d6 ) and sonicated so that a gel was formed in the NMR analysis tube. Solution HSQC NMR spectra of different plant materials representative for hardwood (Eucalyptus globulus), softwood (Picea abies), and non-woody plants (Agave sisalana) are presented here. The spectra show signals corresponding to those of the main plant constituents, such as lignin and polysaccharides. The lignin signals were assigned by comparing the HSQC spectra of the whole plant materials with the HSQC spectra of their respective milled-wood lignins (MWLs). In general terms, the major lignin structural features, such as the relative abundances of the main lignin substructures, the syringyl/guaiacyl ratios and the extent of γ-acetylation of the lignin side-chain observed in the HSQC spectra of the whole plant materials, matched those obtained from the HSQC spectra of the isolated MWLs. Therefore, this technique, which needs only minor amounts of lignocellulosic material and minimal sample preparation, can be useful for the rapid screening of plant lignins without the need for tedious and time-consuming lignin isolation procedures.

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