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61.
Changes in the acid-base properties of titanium(IV), zirconium(IV), iron(III), chromium(III), and indium(III) hydrogels of
oxide hydroxides induced by aging in sodium chloride and sulfate solutions were studied by the point of zero charge method.
On aging in a solution of the sulfate electrolyte the hydrogels loose their basic properties much more rapidly than in the
chloride solution. The most changes were observed in the region of high pH of the point of zero charge of the hydrogels. The
changes in the acid-base properties can be explained by a decrease in the content of surface OH groups with are displaced
by the supporting electrolyte ions, and due to the oxolation of the hydrogels.
Published inIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1329–1332, August, 2000. 相似文献
62.
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
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N. N. Kruk A. S. Starukhin N. Zh. Mamardashvili V. B. Sheinin Yu. B. Ivanova 《Journal of Applied Spectroscopy》2007,74(6):831-837
We have studied quenching of the fluorescence of the diprotonated form of 3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrin
by iodide ions in solutions. We have established that there is both static quenching of fluorescence when nonfluorescent complexes
are formed with the iodide ions, as a result of an internal heavy atom effect, and also dynamic diffusion-controlled quenching.
Based on analysis of the dependences of the fluorescence intensity and fluorescence lifetime on the iodide ion concentration
in solution, we suggest using the diprotonated form of this porphyrin as the base compound for designing a fluorescent molecular
receptor for halide ions.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 750–755, November–December, 2007. 相似文献
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Marina V. Bukhtiyarova Aleksandra S. Ivanova Lyudmila M. Plyasova Galina S. Litvak Anna A. Budneva Evgenii A. Paukshtis 《Reaction Kinetics and Catalysis Letters》2008,93(2):375-387
Hexaaluminates SrAl12O19, BaAl12O19 and LaAl11O18 were prepared by co-precipitation of soluble nitrates of Sr, Ba, or La and Al using NH4HCO3 as a precipitating agent with subsequent calcination at 700–1400°C. The samples were characterized by adsorption methods,
thermal analysis (TA and DTG), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy of adsorbed probe
molecules (CO and CDCl3). It was shown that calcination at 1200°C resulted in the formation of single-phase hexaaluminates in all the samples except
for LaAl11O18, where an additional phase was found. The specific surface area of the samples was obtained in the range 16–22 m2/g. After the treatment at comparable conditions, the total concentrations of both surface Lewis acid sites and basic sites
were found to increase in the series: BaAl12O19 < SrAl12O19 < LaAl11O18. However, the strongest basic sites were detected on the surface of BaAl12O19. 相似文献
68.
用共沉淀法制备的镁铝水滑石(Mg/Al物质的量比为3),经一定温度焙烧后,得到“笼”状结构的复合氧化物,并采用反相气相色谱法(IGC)对复合氧化物和混合氧化物(氧化镁和氧化铝)的表面性质进行了研究。实验测得一系列探针分子在复合氧化物和混合氧化物上的保留时间,可计算出其吸附热力学函数(吸附自由能(ΔG?),吸附焓(ΔH?),吸附熵(ΔS?)),表面能色散组分(γSd)及复合氧化物的表面酸碱参数(KA,KD),并探讨了探针分子在复合氧化物上的吸附机理。结果表明,探针分子进入复合氧化物的“笼”状结构后,可以减小温度对探针分子吸附过程的影响。此外,计算出复合氧化物的表面酸碱参数KA=3.21及KD=21.02,定量地表明镁铝复合氧化物是一种两性偏碱的材料。 相似文献
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