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The role of hydroxyl and oxyl anion radicals in selectivity of oxygen delignification
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Jean Bouchard
Published/Copyright:
January 14, 2010
Abstract
The concentration of the hydroxyl radical generated during oxygen delignification was measured with a radical trapping agent. The N,N′-(5-nitro-1,3-phenylene)-bisglutaramide (NPG) was found to be effective but the experiments revealed that at pH higher than 11.5 the anionic form of hydroxyl radical – the oxyl anion radical – causes up to four times more chain cleavage than the hydroxyl radical. It was also found that the effect of both radicals in the pulp moderated at higher partial oxygen pressure and in the presence of hemicelluloses. The implications are that selectivity can be improved by maintaining a moderate alkaline pH profile, increasing the oxygen partial pressure, and retaining hemicelluloses in the brownstock.
Keywords: bleached pulp; bleaching; cellulose degradation; delignification; hydroxyl groups; oxygen radicals; selectivity
Received: 2009-3-10
Accepted: 2009-9-28
Published Online: 2010-01-14
Published Online: 2010-01-14
Published in Print: 2010-02-01
©2010 by Walter de Gruyter Berlin New York
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Articles in the same Issue
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- Recombinant manganese peroxidase (rMnP) from Pichia pastoris. Part 1: Kraft pulp delignification
- Recombinant manganese peroxidase (rMnP) from Pichia pastoris. Part 2: Application in TCF and ECF bleaching
- The role of hydroxyl and oxyl anion radicals in selectivity of oxygen delignification
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- Synchrotron X-ray fiber diffraction study on the thermal expansion behavior of cellulose crystals in tension wood of Japanese poplar in the low-temperature region
- Studies on the dehydrogenative polymerization of monolignol β-glycosides. Part 6: Monitoring of horseradish peroxidase-catalyzed polymerization of monolignol glycosides by GPC-PDA
- Reactivity of syringyl quinone methide intermediates in dehydrogenative polymerization. Part 2: pH effect in horseradish peroxidase-catalyzed polymerization of sinapyl alcohol
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- Alteration of the unsteady sorption behaviour of maple (Acer pseudoplatanus L.) and spruce (Picea abies (L.) Karst.) due to thermal modification
- Towards improved understanding of PEG-impregnated waterlogged archaeological wood: A model study on recent oak
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- Obituary
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Keywords for this article
bleached pulp;
bleaching;
cellulose degradation;
delignification;
hydroxyl groups;
oxygen radicals;
selectivity
Articles in the same Issue
- Original Papers
- Recombinant manganese peroxidase (rMnP) from Pichia pastoris. Part 1: Kraft pulp delignification
- Recombinant manganese peroxidase (rMnP) from Pichia pastoris. Part 2: Application in TCF and ECF bleaching
- The role of hydroxyl and oxyl anion radicals in selectivity of oxygen delignification
- Thermal aging of 1-alkyl-3-methylimidazolium ionic liquids and its effect on dissolved cellulose
- Synchrotron X-ray fiber diffraction study on the thermal expansion behavior of cellulose crystals in tension wood of Japanese poplar in the low-temperature region
- Studies on the dehydrogenative polymerization of monolignol β-glycosides. Part 6: Monitoring of horseradish peroxidase-catalyzed polymerization of monolignol glycosides by GPC-PDA
- Reactivity of syringyl quinone methide intermediates in dehydrogenative polymerization. Part 2: pH effect in horseradish peroxidase-catalyzed polymerization of sinapyl alcohol
- Fractionation, analysis, and PCA modeling of properties of four technical lignins for prediction of their application potential in binders
- New model for predicting tensile strength and density of eucalyptus handsheets based on an activation parameter calculated from fiber distribution characteristics
- Extractives of the tropical wood wallaba (Eperua falcata Aubl.) as natural anti-swelling agents
- Surface properties of extracts from cork black condensate
- Effect of helium DBD plasma treatment on the surface of wood samples
- Preparation of thermoplastic molding from steamed Japanese beech flour
- Alteration of the unsteady sorption behaviour of maple (Acer pseudoplatanus L.) and spruce (Picea abies (L.) Karst.) due to thermal modification
- Towards improved understanding of PEG-impregnated waterlogged archaeological wood: A model study on recent oak
- Determination of the change in appearance of lumber surfaces illuminated from various directions
- A study of water exchange in wood by means of 2D NMR relaxation correlation and exchange
- Measurement of surface growth stress in Eucalyptus nitens Maiden by splitting a log along its axis
- Obituary
- Dion Chen-Loung Chen (1930–2009)
- Meetings
- Meetings
