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| 4. |
- Sjöblom, Rolf
(författare)
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Molecular reorientations in some hydrogen bonded solids
- 1975
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Proton magnetic resonance second moments and relaxation times at various temperatures are reported for tri- and dimethyl ammonium iodide, bromide, chloride and hydrogen oxalate, and for most of the twenty common amino acids. A general procedure is described for the calculation of theoretical second moments and relaxation times in dipolar solids. In several cases, this procedure is applied to determine the molecular reorientations present as well as the corresponding activation barriers. The results are discussed with particular reference to hydrogen bonding.
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| 5. |
- 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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| 7. |
- 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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| 8. |
- 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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| 9. |
- Petersson, Göran, 1941, et al.
(författare)
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Formation of glucopyranosylglycolic acids during the hydrolysis of cellulose
- 1969
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Ingår i: Svensk Papperstidning. ; 72:7, s. 222-225
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Tidskriftsartikel (refereegranskat)abstract
- A solution of glucose and glycolic acid in hydrochloric acid gives rise to the alpha- and beta forms of glucopyranosylglycolic acid when evaporated. Polymerized glycolic acid is formed as well. These reactions complicate analysis of cellulose degradation materials.
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| 10. |
- Abrahamsson, Jonas, 1954, et al.
(författare)
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Cholesteryl sulphate and phosphate in the solid state and in aqueous systems.
- 1977
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Ingår i: Chemistry and physics of lipids. - 0009-3084. ; 19:3, s. 213-22
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Tidskriftsartikel (refereegranskat)abstract
- Cholesteryl sodium sulphate (CS) crystallizes as the dihydrate, the crystal structure of which is known. On heating the dihydrate, solid state phase transitions are observed at 65 degrees C and 95 degrees C and melting occurs at 165 degrees C. The structure of the high temperature phase has not been determined. Cholesteryl dihydrogen phosphate (CP) is not isostructural with any phases of CS. It undergoes a phase transition at 50 degrees C and melts at 190 degrees C. In systems with water CS is unstable whereas it was possible to determine the phase diagram of CP. In most of the composition range a crystalline hydrate is in equilibrium with a gel-phase. The latter has remarkable properties in that lamellar order exists with the 46 A lipid bilayer interleaved with water layers up to 1000 A. The monofilm behaviour of CS and CP at different pH levels is also reported.
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