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Enthalpies of formation of 1,10-phenanthrolinium ion and ferrous-1,10-phenanthroline (tris) complex in dioxane—water and ethanol—water media at 25°C have been determined by calorimetry. Results are discussed in the light of ion—solvent and solvent—solvent interactions. 相似文献
47.
Tara Chandra Gupta Abani K. Bhattacharya 《Fresenius' Journal of Analytical Chemistry》1960,172(6):428-430
Summary The only method recommended for the direct estimation of ferric iron in presence of HCl is to reduce the ferric iron to ferrous iron and then to titrate against KMnO4 solution by adding Reinhardt-Zimmermann reagent (MnSO4 + H2SO4 + H3PO4). The solubility of the phosphato complexes of ferric chloride and phosphoric acid is much reduced by adding a nonaqueous solvent, ethyl alcohol or acetone. This property has been availed of to find out a method of estimating ferric iron directly against standard solution of phosphoric acid in aqueous-nonaqueous medium using K4Fe(CN)6 or cupferron as external indicators. A slight discrepancy at the end point, however, exists in the direct titration but it can be removed by applying a correction factor determined from the estimated results. 相似文献
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From the roots of oat (Avena sativa) a second antibiotic active glycoside, avenacine B, was isolated in addition to the main glycoside avenacine A. In the aglycone of A the double bond could not be established contrary to the statement in the literature but an aldehyde group in addition to the keto group was identified and therefore the proposed structure has to be revised. In the aglycone of B the —CH2OH-group of A has been substituted by CH3. The structures of the sugar chains in both glycosides have been determined, in avenacine A as [β-d-gluco-pyranosyl(1 → 4)-[β-d-glucopyranosyl (1 → 2)]-α-l-arabinosyl (1)- and in B as [β-d-glucopyranosyl (1 → 4)]-β-d-glucopyranosyl (1)-. 相似文献
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A density-functional theory is presented to study the structure of polymers, having attractive interactions, confined between attractive surfaces. The theory treats the ideal-gas free-energy functional exactly and uses weighted density approximation for the hard-chain contribution to the excess free-energy functional. The bulk interactions of freely jointed hard spheres are obtained from generalized Flory equation of state and the attractive interactions are calculated using the direct correlation function obtained from the polymer reference interaction site model theory along with the mean spherical approximation closure. The theoretical predictions are found to be in quite good agreement with the Monte Carlo simulation results for varying densities, chain lengths, and different interaction potentials. The results confirm important implications of using different approximations for the hard-sphere and attractive interactions. 相似文献
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Abstract —Chloride anions, when added to DCMU [3-(3,4-dichlorophenyl)-1,1-dimethylurea]-treated spinach chloroplasts, change the rate of decay of the delayed light emission in the seconds region but do not change the shape or the temperature dependence of the decay. Benzoate anions, on the other hand, change both the rate and the shape of the decay of the delayed light emission. These results are consistent with a model in which the membrane potential and the structure of the reaction center affect the decay kinetics of the delayed light emission in the seconds region. 相似文献