Kinetic Study on Delignification of Kraft-AQ Pine Pulp with Hydrogen Peroxide Catalyzed by Mn(IV)-Me4DTNE
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Yu Cui
Summary
The kinetics of delignification of a kraft-AQ southern pine pulp with hydrogen peroxide catalyzed by [LMn(IV)(μ-O)3Mn(IV)](ClO4)2 (1), where L = 1,2-bis(4,7-dimethyl-1,4,7-triazacyclonon-1-yl)ethane was studied. The degree of delignification was significantly improved by using the catalyst. The pulp was bleached for 2 hours at 80°C, in 10% consistency with 2% NaOH, 4% H2O2 and 60 ppm catalyst charges on pulp (O.D.). Kappa number of the pulp was reduced from 31.6 to 16.8 corresponding to a degree of delignification of approximately 4%, while GE brightness was increased from 24.2 to 44.7. At the same time, viscosity of the resulting pulp was reduced from 31.1 mPa•s to 20.1 mPa•s compared to the reduction from 31.1 mPa•s to 20.1 mPa•s in the uncatalyzed bleaching under the same reaction condition. This indicates that the degradation of the carbohydrates was moderate in the catalyzed bleaching compared to the uncatalyzed bleaching. The delignification was found to follow pseudo first order kinetics with respect to kappa number, i.e., residual lignin, in the initial phase and quickly slowed down after 30 minutes (residual phase) under all the reaction temperatures investigated. The delignification rate constants in the initial phase were 0.17, 0.18, and 0.21 min−1 at 50, 60, and 80°C, respectively. Degree of delignification at the delignification time of 30 minutes is approximately 40% at 80°C. The possible delignification mechanism was discussed on the basis of the kinetic studies and lignin model compound experiments.
Copyright © 2000 by Walter de Gruyter GmbH & Co. KG
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- Degradation of Model Compounds for Cellulose and Lignocellulosic Pulp during Ozonation in Aqueous Solution
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- Kinetic Study on Delignification of Kraft-AQ Pine Pulp with Hydrogen Peroxide Catalyzed by Mn(IV)-Me4DTNE
- An Analysis of Rolling Shear of Spruce Wood by the Iosipescu Method
- An Investigation of the Crack Tendency on Wood Surfaces After Different Machining Operations
- Microfibril Angle Determination of Rattan Fibers and its Influence on the Properties of the Cane
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- Literature Reports
Articles in the same Issue
- Dielectrically Observed Consequences of Microbial Treatment of Wood and Bamboo
- Adsorption of Cr(VI) from Dichromate Solutions onto Black Locust Leaves
- Electron Paramagnetic Resonance Spectroscopic (EPR) Study of Copper Amine Treated Southern Pine in Wood Preservation
- Comparative Studies of Hemicelluloses Solubilized during the Treatments of Maize Stems with Peroxymonosulfuric Acid, Peroxyformic Acid, Peracetic Acid, and Hydrogen Peroxide. Part 1. Yield and Chemical Characterization
- Homolytic Scission of Interunitary Bonds in Lignin Induced by Ultrasonic Irradiation of MWL Dissolved in Dimethylsulfoxide
- Eucalyptus globulus Kraft Pulp Residual Lignins. Part 1. Effects of Extraction Methods upon Lignin Structure
- Lignin Behavior During the Autocatalyzed Methanol Pulping of Eucalyptus globulus Changes in Molecular Weight and Functionality
- Lignin Degradation in Oxygen Delignification Catalysed by [PMo7V5O40]8- Polyanion. Part I. Study on Wood Lignin
- Biobleaching of Pulp with Dioxygen in the Laccase-Mediator System. Part 1. Kinetics of Delignification
- Degradation of Model Compounds for Cellulose and Lignocellulosic Pulp during Ozonation in Aqueous Solution
- Application of a Catalyst in Peroxide Bleaching of Eucalyptus Kraft Pulp
- Kinetic Study on Delignification of Kraft-AQ Pine Pulp with Hydrogen Peroxide Catalyzed by Mn(IV)-Me4DTNE
- An Analysis of Rolling Shear of Spruce Wood by the Iosipescu Method
- An Investigation of the Crack Tendency on Wood Surfaces After Different Machining Operations
- Microfibril Angle Determination of Rattan Fibers and its Influence on the Properties of the Cane
- Effects of Element Size and Orientation in the Production of High Strength Resin Impregnated Wood Based Materials
- Literature Reports
