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A. V. Rokhin L. V. Kanitskaya D. F. Kushnarev G. A. Kalabin L. S. Smirnova Kh. A. Abduazimov B. Kh. Pulatov 《Chemistry of Natural Compounds》1994,30(6):745-753
A comparative analysis has been made of the dioxane lignins of the stems, seedling shoots, and seed coats of the cotton plant. The ratio of p-hydroxyaromatic, guaiacyl, and syringyl units in the macromolecules of the lignins has been determined, and so have the amounts of functional groups and bonds. It has been established that the main difference between the dioxane lignins from seedling shoots and seed coats of the cotton plant, on the one hand, and the lignin from the woody stems, on the other hand is a lower content of syringyl and guaiacyl units in the former. 相似文献
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L. B. Belykh Yu. Yu. Titova A. V. Rokhin F. K. Shmidt 《Russian Journal of Applied Chemistry》2010,83(11):1911-1918
A new approach to synthesis of nickel catalysts under the action of lithium tetrahydroaluminate was proposed which allows
preparation of high-performance nanosized catalytic systems with well-reproducible properties. The major stages of formation
and the nature of catalytically active species and inhibitors formed in the Ni(acac)2-LiAlH4 system were determined. The catalytic properties of the nickel nanoclusters were studied in relation to the nature and concentration
of the proton-containing compounds. Factors responsible for the promoting action exhibited by these compounds were analyzed. 相似文献
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Galactomannans with galactose:mannose ratios 1:1.48 and 1:1.33, [α]D +67.9 and +76.4°, [η] 870.3 and 1337.1 mL/g, and molecular weights 999 and 1549 kDa, respectively, were isolated in 0.59
and 4.65% yields (of seed mass) from seeds of Astragalus alpinus and A. tibetanus (Fabaceae). Physicochemical methods (CrO3 oxidation; methylation–GC/MS; IR, NMR, and 13C spectroscopy) found that the main polysaccharide chain consisted of 1,4-β-D-mannopyranose units substituted 67.5% (A. alpinus) and 75.2% (A. tibetanus) at the C-6 position by single α -D-galactopyranose units. The contents of mannobiose blocks Man–Man, (Gal)Man–Man/Man–Man(Gal), and (Gal)Man–Man(Gal) variously
substituted with galactose were according to 13C NMR spectroscopy 15.9, 55.5, and 28.6% in A. alpinus galactomannan and 9.9, 42.3, and 47.8% in A. tibetanus galactomannan. 相似文献
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L. S. Smirnova A. V. Rokhin L. V. Kanitskaya D. F. Kushnarev G. A. Kalabin Kh. A. Abduazimov B. Kh. Pulatov 《Chemistry of Natural Compounds》1996,32(2):205-207
A schematic structure has been proposed for an average fragment of the macromolecule of cottonplant dioxane lignin on the basis of the results of a chemical study and quantitative1H and13C NMR spectroscopy.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 234–236, March–April, 1996. Original article submitted June 27, 1994. 相似文献
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Seeds of Astragalus cicer L. (Fabaceae) afforded a galactomannan (5.90% yield of seed mass) of molecular weight 1064 kDa, solutions of which had high
viscosity [η] 925.5 mL/g and optical activity [α]D +71.9°. The galactomannan consisted of galactose and mannose units in a 1:1.39 ratio. Physicochemical methods established
that the main chain of the polysaccharide consisted of 1,4-β-D-mannopyranose units substituted at 72% of the C-6 positions by single α-D-galactopyranose units. The content of variously substituted galactose mannobiose units Man–Man, (Gal)Man–Man/Man–Man(Gal)
and (Gal)Man–Man(Gal) in the galactomannan were 18.7, 19.8, and 61.5%, respectively. 相似文献
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L. B. Belykh N. I. Skripov L. N. Belonogova A. V. Rokhin F. K. Shmidt 《Russian Journal of General Chemistry》2009,79(1):92-97
Reaction of palladium bisacetylacetonate with elemental phosphorus in an inert atmosphere is shown to proceed as a redox process forming palladium phosphides of different compositions: PdP2, Pd5P2, Pd4,8P, and Pd12P3,2. The conversion of Pd(acac)2 and the composition of palladium phosphides formed in benzene is established to be affected by water. A tentative scheme of the formation of palladium phosphides is suggested. 相似文献
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L. B. Belykh T. V. Goremyka A. V. Rokhin Yu. Yu. Titova V. A. Umanets F. K. Schmidt 《Russian Journal of Coordination Chemistry》2005,31(10):719-724
Reactions of Pd(Acac)2 and Pd(Acac)2PPh3 complexes with triethylaluminium in an inert atmosphere are studied by the NMR and IR, electronic microscopy, and X-ray powder diffraction methods. The final products of conversion of the initial Pd(II) complexes are the Pd(0) nanoparticles with the predominant diameter 2–4 nm. The main factors determining the size of Pd(0) particles and the nature of the ligand shell are considered. 相似文献
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Mazyar N. L. Annenkov V. V. Kruglova V. A. Anan'ev S. M. Danilovtseva E. N. Rokhin A. V. Zinchenko S. V. 《Russian Chemical Bulletin》2000,49(12):2013-2017
The interaction of poly(1-vinylimidazole) and poly(1-vinyl-1,2,4-triazole) with HCl and alkalies in aqueous and water-salt solutions was investigated by potentiometric titration, viscosimetry, 1H and 13C NMR, and UV spectroscopy. The effect of the nature and concentration of low-molecular counterions was found. The interaction of poly(1-vinylazoles) with the acid results in the protonation of the azole cycle. The interaction of poly(1-vinylazoles) with alkalies is stipulated by the capability of the pyridine N atom of forming a coordination bond with the metal ion and that of the unsaturated pi-system of the heterocycle of coordinating with the anions. 相似文献