New Method to Follow the Dimerisation Reaction Occuring during Oxidation of 4-Ethylguaiacol
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V. Sippola
Summary
4-Ethylguaiacol is a phenolic model compound used to study the oxidation of lignin. A new method was developed to determine 4,4′-diethyl-6,6′-biguaiacol, an unwanted side-product, in the oxidation of 4-ethylguaiacol. The sample is extracted with ethyl acetate to separate 4,4′-diethyl-6,6′-biguaiacol from the water-soluble oxidation catalyst. No other treatment is required before analysis with a standard UV-Vis spectrophotometer. The spectrophotometer is calibrated to measure concentrations of 4,4′-diethyl-6,6′-biguaiacol up to 0.3 mM. With the new method, the concentrations of 4,4′-diethyl-6,6′-biguaiacol can be reliably determined over a wide alkaline pH range. The performance of the method was demonstrated in experiments investigating the formation of 4,4′-diethyl-6,6′-biguaiacol in the autoxidation and cobalt-sulphosalen catalysed oxidation of 4-ethylguaiacol. In the conditions of the studies (1 bar oxygen pressure and 50°C), a low (0.01 mM) concentration of Co-sulphosalen clearly increased the total conversion of 4-ethylguaiacol. However, relative to autoxidation, the conversions achieved in the presence of the catalyst were just as sensitive to pH, and the yields of the undesired dimeric product, 4,4′-diethyl-6,6′-biguaiacol, were higher.
Copyright © 2002 by Walter de Gruyter GmbH & Co. KG
Articles in the same Issue
- Subject Index
- Author Index
- Contents
- Species Index
- Molecular Identity of Species and Isolates of the Coniphora Cellar Fungi
- Seasonal Variation of Oleoresin Terpenoids from Pinus halepensis and Pinus pinea and Host Selection of the Scale Insect Marchalina hellenica (Homoptera, Coccoidea, Margarodidae, Coelostonidiinae)
- Modification of Spruce Lignans with Trametes hirsuta Laccase
- Formation of 13C-Enriched Cell-Wall DHP Using Isolated Soft Xylem from Picea abies
- Alkaline Hydrolysis of Nonphenolic β-0-4 Lignin Models: Substituent Effect of the A-Ring on the Rate
- Photosensitized Delignification of Residual Lignin and Chemical Pulp from Eucalyptus grandis Wood
- New Method to Follow the Dimerisation Reaction Occuring during Oxidation of 4-Ethylguaiacol
- Methylation Analysis as a Tool for Structural Analysis of Wood Polysaccharides
- Surface Chemistry of Eucalyptus Wood Pulp Fibres: Effects of Chemical Pulping
- Delignification Mechanism during High-Boiling Solvent Pulping. Part 2. Homolysis of Guaiacylglycerol-β-Guaiacyl Ether
- The Further Chemistry of Ellagic Acid III: The Effect of Wick Action upon Moisture Uptake and Movement in Ellagate Treated Pinus radiata Wood
- Influence of Heat and Loading Time on the Mechanical Properties of Calamus merrillii Becc.
- Magnetic Resonance Studies of Thermally Modified Wood
- Dielectric Relaxation Based on Adsorbed Water in Wood Cell Wall under Non-Equilibrium State. Part 3. Desorption
- Influence of Coating Additives on Water Vapour Absorption and Desorption in Norway Spruce
- In situ Longitudinal Tensile Tests of Pine Wood in an Environmental Scanning Electron Microscope
- Literature Reports
Articles in the same Issue
- Subject Index
- Author Index
- Contents
- Species Index
- Molecular Identity of Species and Isolates of the Coniphora Cellar Fungi
- Seasonal Variation of Oleoresin Terpenoids from Pinus halepensis and Pinus pinea and Host Selection of the Scale Insect Marchalina hellenica (Homoptera, Coccoidea, Margarodidae, Coelostonidiinae)
- Modification of Spruce Lignans with Trametes hirsuta Laccase
- Formation of 13C-Enriched Cell-Wall DHP Using Isolated Soft Xylem from Picea abies
- Alkaline Hydrolysis of Nonphenolic β-0-4 Lignin Models: Substituent Effect of the A-Ring on the Rate
- Photosensitized Delignification of Residual Lignin and Chemical Pulp from Eucalyptus grandis Wood
- New Method to Follow the Dimerisation Reaction Occuring during Oxidation of 4-Ethylguaiacol
- Methylation Analysis as a Tool for Structural Analysis of Wood Polysaccharides
- Surface Chemistry of Eucalyptus Wood Pulp Fibres: Effects of Chemical Pulping
- Delignification Mechanism during High-Boiling Solvent Pulping. Part 2. Homolysis of Guaiacylglycerol-β-Guaiacyl Ether
- The Further Chemistry of Ellagic Acid III: The Effect of Wick Action upon Moisture Uptake and Movement in Ellagate Treated Pinus radiata Wood
- Influence of Heat and Loading Time on the Mechanical Properties of Calamus merrillii Becc.
- Magnetic Resonance Studies of Thermally Modified Wood
- Dielectric Relaxation Based on Adsorbed Water in Wood Cell Wall under Non-Equilibrium State. Part 3. Desorption
- Influence of Coating Additives on Water Vapour Absorption and Desorption in Norway Spruce
- In situ Longitudinal Tensile Tests of Pine Wood in an Environmental Scanning Electron Microscope
- Literature Reports
