Metal chelate exchange in the organic phase-II Extraction and exchange constants of dithizonates and diethyldithiocarbamates

Dithizonates and diethyldithiocarbamates of Ag, Tl(I), Cu(II), Zn, Cd, Hg(II), Pb, Fe(II), Co(II), Ni, Pd(II), In(III), As(III), Sb(III), Bi, Se(IV) and Te(IV) have been prepared and their reactions in carbon tetrachloride have been studied spectrophotometrically. From the exchange constants determined, the extraction constants of metal diethyldithiocarbamates have been calculated. Where formation of mixed chelates has been observed, corresponding exchange constants have been determined. Finally, the influence of organic solvents (CCl(4), CHCl(3), C(6)H(6) and C(6)H(5)Cl) on the exchange reaction of zinc diethyldithiocarbamate with dithizone has been investigated.     

Magnetic moments and the high field susceptibilities of MnFe2O4

An extended version of the noncollinear spin model bySawatzky et al. is developed to derive a dependence of the differential high field susceptibility on the degree of inversion of the ferrite MnFe₂O₄. Using the available data on the main molecular field coefficients it is shown that the present model imposes restrictions on values of. Determination of from the measurements of the field dependence of the saturated moments at low temperatures on samples with varying degrees of inversion reveals good quantitative agreement with the present model.     

Extraction of Am(III) in the presence of lanthanides and yttrium by benzyldimethyldodecylammonium nitrate from acidic nitrate solutions

We have investigated the effect of coextraction of lanthanides and yttrium on the distribution coefficients D_Am in the extraction of americium by benzyldimethyldodecylammonium nitrate (BDMLNNO₃) from nitrate solutions. In the coextraction of lanthanides, the extraction of Am(NO₃)₃ is suppressed, which is markedly manifested in the extraction of light lanthanides (La, Ce, Pr); of the series of lanthanides their extraction is the highest. The effect of nitric acid and the possibility of separation of lanthanides and americium by the application of three-stage multiple extraction is discussed.     

Distribution of fallout radionuclides through soil surface layer

The distribution of¹³⁷Cs through soil layers has been investigated by field sampling. The investigation deals with¹³⁷Cs concentration found after the Chernobyl accident. The relationship between important soil characteristics, total precipitation and cesium distribution are analyzed. Cesium is strongly sorbed in the top soil layer and its migration downward is limited. Measurements performed over a 3-year period revealed that approximately 20–38 per cent of total¹³⁷Cs is located in the upper soil layer.     

Preparation and stereoselectivity of 1,3-dipolar cycloaddition ofD-glucose-derived nitrones to N-arylmaleimides

Summary Nitrones2 derived fromD-glucose oxime and benzaldehydes without employing any protection of hydroxyl group were isolated in pure state. The 1,3-dipolar cycloaddition of2 to N-arylmaleimides gave predominantly theanti isoxazolidines3 and was rationalized byZ/E isomerization of N-glycosylnitrones2. The structure and steric configuration of the products have been assigned on the basis of¹H- and¹³C-NMR spectroscopy. AM1 calculations of the nitrones and MM2 calculations of the adducts were performed.

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Darstellung und Stereoselektivität der 1,3-dipolaren Cycloaddition vonD-Glucose-abgeleiteten Nitronen an N-Arylmaleimiden

Zusammenfassung Die Nitrone2 wurden ausD-Glucoseoxim und Benzaldehyden ohne Schutz von Hydroxylgruppen in reinem Zustand erhalten. Die 1,3-dipolare Cycloaddition von2 an N-Arylmaleimiden ergab bevorzugt dieanti-Isoxazolidine3; dies wurde über eineZ/E-Isomerisierung der N-Glycosylnitrone2 rationalisiert. Struktur und Stereochemie wurden auf Basis von¹H- und¹³C-NMR-Spektroskopie ermittelt. Außerdem wurden AM1-Berechnungen an den Nitronen und MM2-Rechnungen an den Addukten ausgeführt.

     

Die Reaktion der Ferrisalze mit der Isonitroso-thioglykolsäure

Zusammenfassung Die Farbreaktion der Ferrisalze mit der Isonitroso-thioglykolsäure wurde durch die Isolierung dreier basischer innerer Komplexsalze mit 1 bzw. 2 Mol der Säure aufgeklärt (I, II, III). Das Eisen bindet mit der Hauptvalenz das Schwefelatom, mit der Nebenvalenz den Sauerstoff der Carbonylgruppe. Erfassungsgrenze der blauen Färbung 3 Eisen bei der Grenzkonzentration 1:7333000.

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Summary The colour reaction of the ferric salts with the isonitrosothioglycolic acid was enlightened by the insulation of three basic inner complex salts with 1, respectively 2 moles of the acid (I, II, III). The iron is fixed by the principal valency to the sulphur atom, by the secondary valency to the oxygen of the carbonyl group. Limit of identification of the blue colour 3 Fe; concentration limit 1:7333000.

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Résumé (W) Le réaction colorée des sels ferriques avec l'acide isonitrosothioglycolique a été expliquée en isolant trois sels complexes internes basiques, avec respectivement une ou deux molécules d'acide (I. II, III). Le fer avec valence principale, se lie à l'atome de soufre, tandis qu'avec une valence secondaire, il se lie à l'oxygène du groupe carbonyle. Limite de perceptibilité: 3 de fer, avec une limite de dilution: 1:7333000.

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(Experimentell ausgeführt vonB. Mareth.)

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XVI. Mitteilung: Chem. Listy34, 307 (1940)     

Improved flask-combustion method for phosphorus in petroleum products

Summary An electrical assembly for the oxygen-flask combustion of lubricants and similar petroleum products is described. The pyrolysis is performed in two consecutive steps. After the ignition and burning of the sample (sorbed on sodium carbonate) the combustion is completed by further heating. The sample weight should not exceed 140 mg. In this way the sensitivity of phosphorus determination of the tentative IP standard procedure is enhanced from 0.01 to 0.001% phosphorus if the volume of solution for the final spectrophotometric measurement is reduced.

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Zusammenfassung Ein elektrisches Gerät für die Verbrennung von Schmierölen und ähnlichen Erdölprodukten im Schöniger-Kolben wurde beschrieben. Die Pyrolyse erfolgt in zwei aufeinander folgenden Schritten. Nach der Entflammung der an Natriumcarbonat adsorbierten Probe und nach Erlöschen der Flamme erfolgt die vollständige Verbrennung von Einwaagen, die 140 mg nicht überschreiten. So konnte die Empfindlichkeit der Phosphorbestimmung nach der tentativen IP-Standardmethode von 0,01% auf 0,001% Phosphor gesteigert werden, wenn man die spektrophotometrische Messung mit vermindertem Lösungsvolumen durchführt.

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Herrn Professor Dr. H. Lieb zum 90. Geburtstag gewidmet.     

Contributions to the basic problems of complexometry-XXI: determination of nickel in the presence of cobalt

A new method for the determination of nickel in the presence of cobalt, based on the masking of the cobalt with potassium cyanide and hydrogen peroxide, is proposed. The yellow, or orange-yellow, complex of cobalt(III) is formed, from which cobalt is not displaced upon the addition of silver nitrate. Tetracyanonickelate, however, reacts quantitatively with silver nitrate, and the displaced nickel can be determined directly with EDTA, using Murexide as indicator. Up to 30 mg of cobalt can be tolerated in the solution.     

Some thermodynamic aspects of highT c superconductors

Thermochemical and thermodynamical properties of HTSC phases are reviewed for the Y-Ba-Cu-O system and also presented for the newly calculated Bi-Sr-Cu-O system stressing out stoichiometric and phenomenological viewpoints. Simulated data are listed for (H ₂₉₈ ^o -H _o ^o , phase transformation temperatures, standard entropies, standard enthalpies of formation, heat capacities in crystalline phase, etc. Pseudobinary phase diagrams are treated showing the effect of oxygen partial pressure particularly illustrated on the (Sr, Bi, Ba)-Cu-O system.The work was carried out under the project No. A 2010532 supported by the Grant Agency of Academy of Sciences of the Czech Republic and the grant No. 104/97/0589 financed by the Grant Agency of the Czech Republic.     

Dilute solution properties of polylaurolactam

For a number of fractions and unfractionated samples of polylaurolactam, molecular weights ($\text{M}{}_{\mathrm{<mtext>w</mtext>}}\text{= 1 × 10}{}^4\text{?12·5 × 10}{}^4$) were measured by the light-scattering method in a mixed solvent of m-cresol with 60 vol. % 2,2,3,3-tetrafluoropropanol; intrinsic viscosities were determined in m-cresol and 96% H₂SO₄, and the constants of the Mark-Houwink equation were calculated. The calculated values of the characteristic ratio of unperturbed dimensions (virtually identical for m-cresol and 96% H₂SO₄) were compared with the respective values for polypyrrolidone and polycaprolactam. It was found that the higher frequency of the CONH-groups reduces the rigidity of the polyamide chain.