The retention behavior of radionuclides on copper(ii)sulfide

The adsorption properties of copper(II) sulfide in various acid solutions for different radiotracers are described. Column and batch equilibration methods are discussed. Copper(II) is selectively adsorbed on CuS; the decontamination factor exceeds 10⁶ for column operations in 6 M hydrochloric acid solution. Among the 30 ions tested in 6 M hydrochloric acid, only copper and gold are adsorbed quantitatively; mercury, silver, bromine, technetium and molybdenum are adsorbed partially. The retention capacity for copper(II) is around 20 mg Cu/g CuS. The adsorption processes on CuS as functions of acid concentrations (HCl, HClO₄ and H₂SO₄) are described. The method seems applicable in activation analysis for trace elements in copper matrices.     

Axially Dissymmetric Chiral (R)‐N,W‐Bis(2‐hydroxy‐3,5‐ditert‐butyl‐arylmethyl)‐1, 1′‐binaphthalene‐2,2′‐diamine as Chiral Ligands in the Reaction of Diethylzinc to Aldehydes†

Chiral ligand (A)‐N,N′‐Bis(2‐hydroxy‐3,5‐di‐tert‐butyl‐arylmethyl)‐1,1′‐binaphthalene‐2,2′‐diamine derived from the reduction of Schiff base (R)‐2,2′‐bis (3,5‐di‐tert‐butyl‐2‐hydroxybenzylideneamino)‐1, 1′‐binaphthyl with LiAlH₄, is fairly effective in the asymmetric addition reaction of diethylzinc to aldehydes by which good yields (46%‐94%) of the corresponding sec‐alcohols can be obtained in moderate ee (51%‐79%) with R configuration for a variety of aldehydes.     

Vapour–liquid equilibrium data for the 1,1,1,2 tetrafluoroethane (R134a) + dimethyl ether (DME) system at temperatures from 293.18 to 358.15 K and pressures up to about 3 MPa

Isothermal vapour–liquid equilibrium data have been measured for the binary system R134a + DME at five temperatures between 293.18 and 358.15 K, and pressures between 0.4899 and 2.9442 MPa. The peculiarity of this system is the existence of an azeotrope with a minimum pressure, which disappears at 358.15 K. The experimental method used in this work is of the static-analytic type, taking advantage of two pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in the CENERG/TEP Laboratory. The data were obtained with uncertainties within ±0.02 K, ±0.0001 MPa and ±1% for molar compositions.

The isothermal P, x, y data are well represented with the Redlich and Kwong equation of state using the Mathias–Copeman alpha function and the Huron–Vidal mixing rules involving the NRTL model.     

SYNTHESIS OF POLYBINAPHTHYLS INCORPORATING CHIRAL （R）-1,1′-BI-2,2′-NAPHTHOL ENTITIES WITH p-DIVINYLBENZENE BY Pd-CATALYZED HECK REACTION

Polymer (Ⅰ) and polymer (Ⅱ) were obtained by the polymerization of (R)-6,6′-dibromo-2,2′-binaphtho-20-crown-6 (M-l) and (R)-6,6′-dibromo-2,2′-di(methoxyethoxymethyloxy)-1,1′-binaphthyl (M-2) with p-divinylbenzene under Pdcatalyzed Heck reaction. The UV, fluorescence and CD spectra of polymer (Ⅰ) and (Ⅱ) are similar due to the same linkers present in their polymer chain. Polymers (Ⅰ) and (Ⅱ) can emit strong blue fluorescence and are expected to have potential applications in polarized blue-light emitting sensors. The chiral conjugated polymers (Ⅰ) and (Ⅱ) exhibit a strong Cotton effect in their circular dichroism (CD) spectra, indicating a high rigidity of polymer backbone.     

Thermal and electrical studies of some polychelates

Polychelates of Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) with 4,4′-dihydroxy-3,3′-diacetylbiphenyl-dithioxamide (DDBDO) have been prepared. Their structures were determined by visible reflectance spectroscopy and magnetic measurements in conjunction with thermogravimetric and IR measurements. Elemental analysis indicates a 1∶1 metal-ligand stoichiometry and the association of water molecules with the central metal. The decomposition temperature of the chelates is in the order Ni(II)>Fe(II)>Co(II)>Mn(II)>Cu(II). Thermal activation energies (E _a ), calculated with the help of Freeman-Carroll and Sharp-Wentworth methods, are in agreement with each other. The polychelates were found to be semiconductive, and the activation energy obtained from semiconducting behavior follows the order Co(II)>Ni(II)>Fe(II)>Cu(II)>Mn(II). The probable structure, such as six coordinated octahedral for Mn(II) and Fe(II) polychelates and four coordinated square planar for Co(II), Ni(II), and Cu(II) polychelates, have been suggested.     

IMMOBILIZATION OF Saccharomyces Cerevisiae USING POLY（ACRYLAMIDE） GEL FOR ASYMMETRIC SYNTHESIS OF R（-）-MANDELIC ACID

In this paper, the poly(acrylamide) hydrogel used to immobilize saccharomyces cerevisiae for asymmetric synthesis of R(-)-mandelic acid was prepared with free radical ploymerization in deionized water at room temperature under nitrogen atmosphere. The influence of the composition of hydrogel, loading amount of cells and culture conditions on the asymmetric synthesis was investigated. Results show that PAAm hydrogel is a feasible carrier for immobilization of cells which is a potential alternative method to prepare enantiomerically pure R(-)-mandelic acid.     

Influence of the head core machining upon the fringing field

Theoretical considerations connected with spacing losses in video-tape recording are presented. The Beilby layer on the head and gap surfaces, residual stress of the head core after machine processing cause great losses at very short wavelength. An analysis of the fringing field has been applied to estimate the equivalent non-magnetic layer. Based on determined experimentally actual permeability in the surface layer incorporated into a boundary-value-problem head model, it can be shown that the spacing losses related to the non-magnetic spacing can be effectively determined in quantitative form. Because of the considerable decrease of permeability in the head core at high frequency machining effects should not be neglected in recording performance considerations. The non-magnetic spacing has been estimated to be 0.26 m at 5 MHz.It seems to be that the fringing field is a very indicative parameter which integrated all structural microeffects occurring in surface layers of machined material in the gap portion.     

Titrimetric microdetermination of silver, lead and cadmium with thioglycollic acid and of mercury(II) with 2-mercaptopropanoic acid

A simple and rapid titrimetric method is described for the microdetermination of Ag(+), Cd(2+) and Pb(2+), based on their formation of mercaptides with a measured excess of 2-mercaptopropanoic acid, and similar determination of Hg(2+) with thioglycollic acid. Univalent and bivalent metal ions release one and two thiol protons respectively, which along with the carboxyl protons of the thiol reagent are titrated with standard alkali. The difference from the blank titration gives the increase in acidity which is a function of the metal-ion concentration. The proposed procedure is applicable to samples containing 0.025-0.25 mmole of these ions, the average deviation being in the range 0.2-0.5%.     

Synthesis of (R,S)-muscone

Construction of the carbon-skeleton of (R,S)-muscone was achieved by reacting methyllithium with the dianion of cyclopentadecanedione-1,3, itself accessible by hydration of cyclopentadecanediyne-1,3.

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Synthese von (R,S)-Muscon (Kurze Mitteilung) Short communication

Zusammenfassung Die Konstruktion des Kohlenstoffgerüstes von (R,S)-Muscon gelingt durch Reaktion des Dianions von Cyclopentadecandion-1,3, das durch Hydratisierung von Cyclopentadecandiin mit Methyllithium erhältlich ist.

     

Reactive intermediates in the photolysis of cyclopentadienylcobalt(I) dicarbonyl and in the reduction of cyclopentadienylcobalt(III) carbonyl diiodide

Photolysis of (C₅H₅)Co(CO)₂ (I) in toluene or petroleum ether solution at ?78°C generates the unsaturated monocarbonyl species (C₅H₅)Co(CO), which was identified in solution by its IR spectrum. At room temperature, this monocarbonyl can associate with excess I to give (C₅H₅)₂Co₂(CO)₃, or dimerize to (C₅H₅)₂Co₂(CO)₂. The latter is stable as a solid, but in solution it is slowly converted to the insoluble trimer (C₅H₅)₃Co₃(CO)₃. (C₅H₅)₂Co₂(CO)₂ is symmetrically cleaved by phosphines to (C₅H₅)Co(CO)(PR₃), while diolefins bring about unsymmetrical cleavage to give (C₅H₅)Co(diolefin) and (C₅H₅)Co(CO)₂.