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Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
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Biljana Bujanovic
Veröffentlicht/Copyright:
8. August 2007
Abstract
Commercial softwood kraft pulp with kappa number 30.5 (KP30.5) was delignified with polyoxometalates (POM, Na5(+2)[SiV1(-0.1)MoW10(+0.1)O40]), and POM-treated kraft pulp of kappa number 23.6 was obtained (KPPOM,23.6). Residual lignin from pulps was isolated by mild acid hydrolysis and characterized by analytical and spectral methods to gain insight into lignin reactions taking place during the initial delignification phase. Lignin from POM-delignified pulp was isolated in lower yield. Comparative analysis of residual lignins (RL-KP30.5, RL-KPPOM,23.6) showed that POM leads to products enriched in carbonyl/carboxyl groups and carbohydrates. POM lignins have a lower molecular mass and a lower content of phenolic hydroxyl and methoxyl groups. Based on these results and FTIR spectra, we suggest that aromatic ring cleavage and quinone formation occur during POM delignification. The degree of lignin-cellulose association increases after POM delignification. Lignin-cellulose association was found to be partially unstable under mild alkaline conditions, as residual lignin isolated after alkaline extraction of KPPOM,23.6 pulp (RL-KPPOM/NaOH) exhibited lower glucose content, higher Klason lignin content, and less extraneous material.
Keywords: acid hydrolysis; commercial softwood kraft pulp; lignin-cellulose association; polyoxometalate delignification; residual lignin
Received: 2006-11-22
Accepted: 2007-6-5
Published Online: 2007-08-08
Published in Print: 2007-8-1
©2007 by Walter de Gruyter Berlin New York
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Artikel in diesem Heft
- Meetings
- Chemical composition of 36 Brazilian Amazon forest wood species
- Characterization of non-cellulosic glucans in Eucalyptus globulus Labill. wood and kraft pulp
- Study of the phenolic compounds formed during pretreatment of sugarcane bagasse by wet oxidation and steam explosion
- Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
- Synthesis of light-colored rosin glycerol ester
- Studies on fluorescence of cellulosics
- Fluorescence spectroscopy for chromophore studies on bleached kraft pulps
- Influence of surface structure on wetting of coated offset papers
- Fundamental study of the interaction of Ti atoms with spruce surfaces
- Surface analysis of groundwood paper treated by diffuse coplanar surface barrier discharge (DCSBD) type atmospheric plasma in air and in nitrogen
- Ultrastructural aspects of fibre development during the stone groundwood process: New insights into derived pulp properties
- Stabilization of peracetic acid with aspartic acid diethoxy succinate (AES)
- Stabilization of H2O2 in the presence of Fe(II) and Mn(II) impurities under alkaline conditions
- Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0–95°C: Hardwood vs. softwood and normal wood vs. reaction wood
- Thermoforming of wood veneer composite sheets
- A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood
- Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test
- Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test
- Determination of Young's modulus and shear modulus by means of deflection curves for wood beams obtained in static bending tests
- Insecticidal activity of essential oil from Chamaecyparis formosensis Matsum
- Knotwood as a window to the indirect measurement of the decay resistance of Scots pine heartwood
- Field assessment of wood stake decomposition in forest soil
Schlagwörter für diesen Artikel
acid hydrolysis;
commercial softwood kraft pulp;
lignin-cellulose association;
polyoxometalate delignification;
residual lignin
Artikel in diesem Heft
- Meetings
- Chemical composition of 36 Brazilian Amazon forest wood species
- Characterization of non-cellulosic glucans in Eucalyptus globulus Labill. wood and kraft pulp
- Study of the phenolic compounds formed during pretreatment of sugarcane bagasse by wet oxidation and steam explosion
- Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
- Synthesis of light-colored rosin glycerol ester
- Studies on fluorescence of cellulosics
- Fluorescence spectroscopy for chromophore studies on bleached kraft pulps
- Influence of surface structure on wetting of coated offset papers
- Fundamental study of the interaction of Ti atoms with spruce surfaces
- Surface analysis of groundwood paper treated by diffuse coplanar surface barrier discharge (DCSBD) type atmospheric plasma in air and in nitrogen
- Ultrastructural aspects of fibre development during the stone groundwood process: New insights into derived pulp properties
- Stabilization of peracetic acid with aspartic acid diethoxy succinate (AES)
- Stabilization of H2O2 in the presence of Fe(II) and Mn(II) impurities under alkaline conditions
- Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0–95°C: Hardwood vs. softwood and normal wood vs. reaction wood
- Thermoforming of wood veneer composite sheets
- A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood
- Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test
- Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test
- Determination of Young's modulus and shear modulus by means of deflection curves for wood beams obtained in static bending tests
- Insecticidal activity of essential oil from Chamaecyparis formosensis Matsum
- Knotwood as a window to the indirect measurement of the decay resistance of Scots pine heartwood
- Field assessment of wood stake decomposition in forest soil
