Atmospheric Acetic Acid Pulping of Rice Straw IV: Physico-Chemical Characterization of Acetic Acid Lignins from Rice Straw and Woods. Part 1. Physical Characteristics
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Xue-Jun Pan
Summary
Lignins obtained by atmospheric acetic acid delignification of rice straw, birch and fir were characterized by molecular weight, solubility and thermomechanical analysis, and by ultraviolet (UV), Fourier transform infra-red (FTIR) and 13C-NMR spectroscopy. Rice straw lignins (rice lignins) were very different from birch and fir lignins. The former was difficult to dissolve in most tested solvents and infusible on heating, while the latter had a good solubility and fusibility. FTIR spectra indicated that the rice lignins had more conjugated and fewer unconjugated carbonyl groups than the wood lignins. 13C-NMR spectra showed that rice lignins had more polysaccharides associated to the lignin and more p-coumaric and ferulic acid than the wood lignins. Concentrations of acetic acid and choice of catalyst (sulfuric or hydrochloric acid) had a considerable effect on the characteristics of rice lignins. Rice lignin obtained with 90% acetic acid than that obtained with 80% acetic acid, and the lignin obtained with sulfuric acid as catalyst than that obtained with hydrochloric acid, had lower molecular weight, better solubility, lower glass-transition temperature and lower UV absorptivity. 80% acetic acid delignified rice straw less effectively than 90% acetic acid.
Copyright © 1999 by Walter de Gruyter GmbH & Co. KG
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- Literature Reports
Artikel in diesem Heft
- The Significance of Accelerated Laboratory Testing Methods Determining the Natural Durability of Wood
- The Thermomechanical Behaviour of Wood Subject to Fungal Decay
- Fixation of Chromium in Wood from Trivalent Chromium Salt Solutions
- Spatial Distribution of Metal Ions in Spruce Wood by Synchrotron Radiation Microbeam X-Ray Fluorescence Analysis
- Chemical Composition of Lipophilic Extractives from Eucalyptus globulus Labill. Wood
- Antifungal Compounds in the Ethyl Acetate Soluble Fraction of the Extractives of Taiwania (Taiwania cryptomerioides Hayata) Heartwood
- Efficacy of Pinosylvins against White-Rot and Brown-Rot Fungi
- Investigations into Laccase-Mediator Delignification of Kraft Pulps
- Cell-Wall-Associated Oxidases from the Lignifying Xylem of Angiosperms and Gymnosperms: Monolignol Oxidation
- Atmospheric Acetic Acid Pulping of Rice Straw IV: Physico-Chemical Characterization of Acetic Acid Lignins from Rice Straw and Woods. Part 1. Physical Characteristics
- Lignin-Polyphenol Interaction in Azobe (Lophira alata) Heartwood. A Study on Milled Wood Lignin (MWL) and Klason Residues
- Electrospray Ionization Mass Spectrometry as a Tool for Lignins Molecular Weight and Structural Characterisation
- Determination of Phenolic Hydroxyl Groups in Lignin by Combined Use of 1H NMR and UV Spectroscopy
- The Effective Diffusion Coefficient and Mass Transfer Coefficient of Nordic Softwoods as Calculated from Direct Drying Experiments
- Stress Relaxation of Sugi (Cryptomeria japonica D.Don) Wood in Radial Compression under High Temperature Steam
- Structural Performance of Fire-Retardant Treated Plywood: Effect of Elevated Temperature
- Sorption Behaviour and Dimensional Changes of Wood-Coating Composites
- Literature Reports
