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Effect of autohydrolysis of Eucalyptus globulus wood on lignin structure. Part 2: Influence of autohydrolysis intensity
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Moritz Leschinsky
Published/Copyright:
November 6, 2008
Abstract
Three different levels of autohydrolysis intensity, expressed as the prehydrolysis (P)-factor, were applied to Eucalyptus globulus wood at a liquor/wood ratio of 5:1. Lignin fractions were isolated from the wood residue as milled wood lignin (MWL), from the hydrolysate by centrifugation (insoluble fraction) and by ethyl acetate extraction (soluble fraction), and from the reactor wall as precipitate. With increasing autohydrolysis duration, a decrease in the content of aliphatic hydroxyl groups and of β-O-4 structures was detected in all lignin fractions, whereas the content of phenolic hydroxyl groups increased in the same order. MWL isolated from wood residue after autohydrolysis at the highest P-factor contained only half the β-O-4 structures contained in native lignin. Molecular weight distribution measurements revealed that fragmentation reactions dominated over condensation reactions in all lignin samples investigated. However, low-molecular-weight lignin dissolved in autohydrolysate exhibited extremely high reactivity towards acid-catalysed condensation reaction, which inevitably leads to the formation of sticky precipitates during storage at elevated temperature under the acid conditions prevailing.
Keywords: autohydrolysis; biorefinery; lignin degradation; milled wood lignin (MWL); NMR; prehydrolysis (P)-factor; prehydrolysis kraft pulping
Received: 2008-6-14
Accepted: 2008-8-15
Published Online: 2008-11-06
Published in Print: 2008-11-01
©2008 by Walter de Gruyter Berlin New York
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Keywords for this article
autohydrolysis;
biorefinery;
lignin degradation;
milled wood lignin (MWL);
NMR;
prehydrolysis (P)-factor;
prehydrolysis kraft pulping
Articles in the same Issue
- Original Papers
- Soda–AQ delignification of poplar wood. Part 1: Reaction mechanism and pulp properties
- Soda-AQ delignification of poplar wood. Part 2: Further degradation of initially dissolved lignins
- Effect of autohydrolysis of Eucalyptus globulus wood on lignin structure. Part 1: Comparison of different lignin fractions formed during water prehydrolysis
- Effect of autohydrolysis of Eucalyptus globulus wood on lignin structure. Part 2: Influence of autohydrolysis intensity
- Extraction of galactoglucomannan from spruce wood with pressurised hot water
- Determination of ethylenic residues in wood and TMP of spruce by FT-Raman spectroscopy
- Quantitative assessment of total phenol contents of European oak (Quercus petraea and Quercus robur) by diffuse reflectance NIR spectroscopy on solid wood surfaces
- Valence band spectroscopy on lignin
- Analysis of acids and degradation products related to iron and sulfur in the Swedish warship Vasa
- Fenton-induced degradation of polyethylene glycol and oak holocellulose. A model experiment in comparison to changes observed in conserved waterlogged wood
- Towards novel wood-based materials: Chemical bonds between lignin-like model molecules and poly(furfuryl alcohol) studied by NMR
- Manufacture of laminated strand veneer (LSV) composite. Part 1: Optimization and characterization of thin strand veneers
- Manufacture of laminated strand veneer (LSV) composite. Part 2: Elastic and strength properties of laminate of thin strand veneers
- Flexural, in-plane shear and nail shear properties of falcataria-rubberwood laminated veneer board for flooring
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- Sorption and thermodynamic properties of juvenile Pinus sylvestris L. wood after 103 years of submersion
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- Short Notes
- Analysis of thermally treated wood samples using dynamic FT-IR-spectroscopy
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- Book review
- Identification of the timbers of Southeast Asia and the Western Pacific
- Personalia
- Prof. Dr. Olaf Schmidt retired at 65
- Contents Volume 62
- Contents Volume 62 (2008)
- Meeting
- Meetings
- Acknowledgement
- Acknowledgement
- Author index
- Author index
- Species index (scientific names)
- Species index (scientific names)
- Subject index
- Subject index
