Gas—liquid chromatography—mass spectrometry studies on pine kraft black liquors : III. The liberation of carboxylic acids in the initial phase of pulping
✍ Scribed by Klaus Niemelä
- Publisher
- Elsevier Science
- Year
- 1988
- Tongue
- English
- Weight
- 416 KB
- Volume
- 446
- Category
- Article
- ISSN
- 1873-3778
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✦ Synopsis
Pine-wood chips were treated with sodium hydroxide at a rather low temperature (40°C) and the products obtained in solution were analysed by capillary gasliquid chromatography-mass spectrometry. In addition to fatty and resin acids, which were the main products, 22 hydroxy monocarboxylic, 18 dicarboxylic and 6 aromatic carboxylic acids were identified as their trimethylsilyl derivatives. Hydroxy monocarboxylic acids (0.09-O. 16% of wood) were primarily carbohydrate degradation products, whereas the dicarboxylic acid fraction (0.07-0.10% of wood) was mainly composed of oxalic and C5-C r0 alkanedioic acids, which were obviously autoxidation products of fatty acids. Aromatic acids included benzoic acid and five lignin-related compounds, of which guaiacylglycolic and guaiacylglyceric acids had not been identified earlier after alkali treatment of softwood.