Lignin Degradation in Oxygen Delignification Catalysed by [PMo7V5O40]8- Polyanion. Part I. Study on Wood Lignin
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D.V. Evtuguin
, C. Pascoal Neto and J. Rocha
Summary
The behaviour of lignin in wood delignification by oxygen in acidic media in the presence of the molybdovanadophosphate heteropolyanion [PMO7V5O40]8−as studied using wet chemistry methods, solid and liquid state 13C NMR spectroscopy. Lignin is oxidised by [PMO7V5O40]8− almost completely to carbon dioxide, with a minor yield of intermediate low-molecular weight aromatic products. The analysis of the reaction products shows that the lignin acidolysis and homolysis involving the oxygen participation in oxidation take place. The residual lignin in the wood residue is more “condensed” and richer in guaiacyl structural units than that in the initial wood. The analysis of “condensed” structures issued from permanganate oxidation of residual lignins suggests that these are formed predominantly by acid-catalysed reactions. The use of an organic solvent, such as ethanol, in the pulping solution favours the oxidative delignification, protecting the lignin against competing reactions (condensation).
Copyright © 2000 by Walter de Gruyter GmbH & Co. KG
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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