Reactions of Lignin with Peroxymonophosphoric Acid: The Degradation of Lignin Model Compounds
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T. Zhu
Summary
Peroxymonophosphoric acid (Pp) has been shown to be an excellent delignification chemical for kraft pulps. However, the reaction mechanism of Pp with lignin has not been elucidated. Therefore, the reactions of Pp with non-phenolic lignin model compounds have been investigated at 70 and 90°C and compared to those of peroxymonosulfuric acid (Px). Pp and Px appear to follow similar reaction pathways, however, the reaction kinetics are significantly different. Both Pp and Px react with 1,2-Dimethoxy-4-methyl-benzene as electrophiles, with aromatic hydroxylation being the main initial reaction. For 1-(3,4-Dimethoxy-phenyl)-ethanone, both Px and Pp react via the Baeyer-Villiger reaction, in which the initial step is nucleophilic attack by the peracid.The reaction with 1-(3,4-Dimethoxy-phenyl)-ethanol occurs primarily via carbocation formation followed by subsequent reactions with the peracid. Changes in pH dramatically affect the reaction rates of Pp with all the model compounds investigated, whereas with the exception of the Baeyer-Villiger reaction, changes in pH did not affect the Px reactions. Below pH 2, Pp is a better electrophile than Px, but above pH 2, Px is better. In addition, while Px remains reactive, Pp is not reactive at pH above 7 for the model compounds investigated.
Copyright © 2003 by Walter de Gruyter GmbH & Co. KG
Articles in the same Issue
- The Relationship Between Variability of Cell Wall Mass of Earlywood and Latewood Tracheids in Larch Tree-Rings, the Rate of Tree-Ring Growth and Climatic Changes
- How Variability in OSB Mechanical Properties Affects Biological Durability Testing
- Microfibril Angles Inside and Outside Crossfields of Norway Spruce Tracheids
- Reactivity of a Fungal Laccase Towards Lignin in Softwood Kraft Pulp
- Lignans and Lipophilic Extractives in Norway Spruce Knots and Stemwood
- Investigation of Lignin Oligomers Using Electrospray Ionisation Mass Spectrometry
- Reactions of Lignin with Peroxymonophosphoric Acid: The Degradation of Lignin Model Compounds
- The Reactions of Lignin Model Compounds with Hydrogen Peroxide at Low pH
- Spin Distribution in Dehydrogenated Coniferyl Alcohol and Associated Dilignol Radicals
- Ultrastructural Localisation of Glucomannan in Kraft Pulp Fibres
- New Method for Quantitative Preparation of Lignin- Carbohydrate Complex from Unbleached Softwood Kraft Pulp: Lignin-Polysaccharide Networks I
- Peroxide Bleaching of Parquet Blocks and Glue Lams
- Easily Degradable Chlorinated Compounds Derived from Glucuronoxylan in Filtrates from Chlorine Dioxide Bleaching of Eucalyptus globulus Kraft Pulp
- Non-Deterministic Description of Wood Radio Frequency Vacuum Drying
- Bending Creep of High-Temperature Dried Spruce Timber
- Optimization of a Violin Top with a Combined Laminate Theory and Honeycomb Model of Wood
- Optimisation of Soda Pulping Variables for Preparation of Dissolving Pulps from Oil Palm Fibre
Articles in the same Issue
- The Relationship Between Variability of Cell Wall Mass of Earlywood and Latewood Tracheids in Larch Tree-Rings, the Rate of Tree-Ring Growth and Climatic Changes
- How Variability in OSB Mechanical Properties Affects Biological Durability Testing
- Microfibril Angles Inside and Outside Crossfields of Norway Spruce Tracheids
- Reactivity of a Fungal Laccase Towards Lignin in Softwood Kraft Pulp
- Lignans and Lipophilic Extractives in Norway Spruce Knots and Stemwood
- Investigation of Lignin Oligomers Using Electrospray Ionisation Mass Spectrometry
- Reactions of Lignin with Peroxymonophosphoric Acid: The Degradation of Lignin Model Compounds
- The Reactions of Lignin Model Compounds with Hydrogen Peroxide at Low pH
- Spin Distribution in Dehydrogenated Coniferyl Alcohol and Associated Dilignol Radicals
- Ultrastructural Localisation of Glucomannan in Kraft Pulp Fibres
- New Method for Quantitative Preparation of Lignin- Carbohydrate Complex from Unbleached Softwood Kraft Pulp: Lignin-Polysaccharide Networks I
- Peroxide Bleaching of Parquet Blocks and Glue Lams
- Easily Degradable Chlorinated Compounds Derived from Glucuronoxylan in Filtrates from Chlorine Dioxide Bleaching of Eucalyptus globulus Kraft Pulp
- Non-Deterministic Description of Wood Radio Frequency Vacuum Drying
- Bending Creep of High-Temperature Dried Spruce Timber
- Optimization of a Violin Top with a Combined Laminate Theory and Honeycomb Model of Wood
- Optimisation of Soda Pulping Variables for Preparation of Dissolving Pulps from Oil Palm Fibre
