| 1. |
- Larsson, Kenneth, et al.
(författare)
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Methanolysis of galacturonic acid
- 1974
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Ingår i: Carbohydrate Research. ; 34, s. 323-329
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Tidskriftsartikel (refereegranskat)abstract
- Dimethyl acetals of galacturono-6,3-lactone and methyl galacturonate are formed during methanolysis of galacturonic acid. The products of methanolysis were studied by ion exchange and gas chromatography. Trimethylsilyl (TMS) derivatives were used in gas chromatography. Structure determinations were made from mass spectra of the TMS derivatives. The course of methanolysis was investigated by means of a gas chromatographic study of the composition of the reaction mixture as a function of time.
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| 2. |
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| 3. |
- Petersson, Göran, 1941
(författare)
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Branched deoxyaldaric acids from alkaline degradation of carbohydrates: Structure determination by mass spectrometry of trimethylsilyl derivatives
- 1975
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Ingår i: Carbohydrate Research. ; 43, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- The deoxyaldaric acids corresponding in structure to the 3-deoxy-2-C-(hydroxymethyl)aldonic (isosaccharinic) acids have been identified as products of treatment of various carbohydrates with alkali and oxygen-alkali. The structures of the acids were determined from the mass spectra of their Me3Si derivatives on the basis of previously known, specific fragmentation reactions. The g.l.c.-m.s. technique was used, and g.l.c. retention data are given. The identified species are 2-deoxy-3-C-(hydroxymethyl)tetraric, 3-deoxy-2-C-hydroxymethyl-erythro-pentaric, 3-deoxy-2-C-hydroxymethyl-threo-pentaric, 2-methyltartronic, 2-(2-hydroxyethyl)tartronic, and 2-(2,3-dihydroxypropyl)tartronic acids. Their formation from 4-O-substituted uronic and ulosonic acids is briefly discussed.
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| 4. |
- Petersson, Göran, 1941, et al.
(författare)
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Formation of 1,4-anhydro-3-deoxypentitol-2-carboxylic acids by alkaline degradation of cellulose
- 1976
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Ingår i: Acta Chemica Scandinavica B. ; 30, s. 27-30
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Tidskriftsartikel (refereegranskat)abstract
- An anhydroisosaccharinic acid obtained in large amounts by end-wise degradation of cellulose in alkaline media, and in small amounts in hydrolysates of cellulose, has been identified as a 1,4-anhydro-3-deoxypentitol-2-carboxylic acid (3-hydroxy-5-(hydroxymethyl)oxolane-3-carboxylic acid). Structural evidence was obtained by GC-MS studies of the compounds (as Me3Si derivatives) obtained on degradation of the acid to 1,4-anhydro-3-deoxypentitol by reduction of the methyl ester followed by periodate oxidation and borohydride reduction. In aqueous alkali, the acid is likely to be formed from a dicarbonyl precursor by benzilic acid rearrangement.
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| 5. |
- Havlicek, Jaroslav, et al.
(författare)
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Partition chromatography and mass spectrometry of tetrulose and pentuloses
- 1972
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Ingår i: Acta Chemica Scandinavica. ; 26, s. 2205-2215
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Tidskriftsartikel (refereegranskat)abstract
- Partition chromatography on ion exchange resins in aqueous ethanol is an excellent tool for the separation of tetrulose and pentuloses for both analytical and preparative purposes. The analysis of complex mixtures is facilitated by the fact that the ketoses are recorded by both the orcinol and periodate-formaldehyde methods whereas under proper conditions aldoses are only recorded in the orcinol channel. In gas chromatography the trimethylsilylated 3-pentuloses gave rise to only one prominent peak which as revealed by mass spectrometry corresponded to the keto form. Tetrulose and the 2-pentuloses gave two or more peaks. The 1,2-enediol derivative obtained from tetrulose was identical with that recorded for threose.
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| 6. |
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| 7. |
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| 8. |
- Löwendahl, Lars, 1940, et al.
(författare)
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Dicarboxylic acids produced by oxygen-alkali treatment of birch xylan
- 1975
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Ingår i: Acta Chem. Scand. B. ; 29:4, s. 526-527
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Tidskriftsartikel (refereegranskat)abstract
- C-(2-Hydroxyethyl)tartronic acid is predominant among the dicarboxylic acids and its formation in 12 % yield makes it a major product from xylan. The structure indicates that it is formed from terminal, oxidized xylose units by beta-elimination at C-4 and subsequent benzilic acid rearrangement. It is proposed that 2-ulosonic acid end-groups or ulosono-1,5-lactone end-groups, related in structure to ascorbic acid, are formed as precursors.
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| 9. |
- Löwendahl, Lars, 1940, et al.
(författare)
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Oxygen-alkali treatment of cellobiose
- 1975
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Ingår i: Acta Chem. Scand. B. ; 29:9, s. 975-980
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Tidskriftsartikel (refereegranskat)abstract
- C-(2,3-Dihydroxypropyl)tartronic acid is a major dicarboxylic acid formed during O2-NaOH and O2-NaHCO3 treatment of cellobiose. The observation that this acid is the main reaction product after alkali treatment ofascorbic acid in O2-free medium supports the conclusion that it is formed via an aglycon moiety related to ascorbic acid. Other dicarboxylic acids from cellobiose are oxalic, tartronic, deoxytetraric, C-(hydroxymethyl)tartronic, and succinic acids.The temperature, pH and additions of iron and cobalt salts strongly influence the product composition. The formation of aldobionic acids from cellobiose parallels the formationof aldonic acid end groups during oxygen bleaching of cellulose.
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| 10. |
- Löwendahl, Lars, 1940, et al.
(författare)
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Phenolic compounds in kraft black liquor
- 1978
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Ingår i: Svensk Papperstidning. ; 81:12, s. 392-396
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Tidskriftsartikel (refereegranskat)abstract
- The prominent phenolic compounds with one aromatic ring in kraft black liquor were analysed by a combination of liquid chromatography, gas chromatography and mass spectrometry. Extracted spruce meal was cooked both under mild, conventional conditions and under extremely severe conditions. In all, the analyzed phenolic compounds amounted to 0.6 kg per 100 kg of dry wood under conventional conditions. In addition to 2-methoxyphenol, vanillin and 4-hydroxy-3-methoxyacetophenone, several phenolic alcohols and carboxylic acids with the same aromatic substitution were isolated and identified. The yield of related 3,4- dihydroxyphenylsubstituted compounds increased under severe conditions.
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