Journal of Inorganic and Nuclear Chemistry最新文献

The extraction of Eu(III) and Am(III) from lithium nitrate solution by several neutral phosphorus-based extractants has been studied as a function of temperature in the range of 0–50°C. From the variation of the distribution ratio with temperature the thermodynamic quantities ΔG, ΔH and ΔS have been calculated for these extractions. The results of this study indicate that these two metal ions behave quite similarly in respect to the basicity and the steric bulk of the extractant molecules. Extraction of these metals is enhanced significantly with increasing basicity of the extractant but is inhibited with increasing steric bulk of the phosphorus compounds.

Carbons possessing unique properties somewhat like those of glassy carbon have been prepared from structural microcrystalline cellulose precursors by prolonged pyrolysis up to 800°C in a nitrogen atmosphere. Samples of the dry microcrystalline cellulose powders were fabricated into various shapes in a high pressure mold or by slow drying of an aqueous suspensoid gel in a mold under ambient conditions. Pyrolysis gave objects of amorphous carbon about one-third the original size. Some of the carbons are about as hard as glass and have a density (helium pycnometer) of 2.01 g/cm³ (cf. graphite 2.265). As expected, the carbon resulting from the pressed microcrystalline cellulose dry powders had a lower density and more pores than carbons produced from structural forms, prepared from air dried, aqueous gels. Pore size and pore size distribution data and scanning electron photomicrographs are shown.

A molybdenum anode can be oxidised electrochemically into acetonitrile/X₂ media (X = Cl, Br, I), with current efficiencies which are lower than for the analogous chromium system. The subsequent work-up of solutions prepared by this method yields products containing molybdenum in either + II or + V oxidation states. A tentative reaction scheme is presented. Tungsten could not be oxidised electrochemically under the conditions used.

The kinetic behavior of the reaction between dihalodicarbonylrhodate(I) anions, [RhX₂(CO)₂]⁻¹, where X = Cl, Br, and the chelating agent 2-aminopyridine was investigated spectrophotometrically. The reaction for both halo analogues was found to obey third order kinetics, first order in the complex anion and second order in the 2-aminopyridine concentrations. The third order rate constants for the chloro and bromo complex anions had the values, at 25°C, of 779 and 156 l² mol⁻² min⁻¹, respectively, and the corresponding activation energies were 3.00 and 5.50 Kcal mol⁻¹. A mechanism is proposed to account for these observations.

Cu(II) complexes have been prepared with N-isopropyl-2-picolinamine N-oxide (IPA) employing the perchlorate, tetrafluoroborate, nitrate, chloride and bromide salts. Preparative molar ratios of 4:1 and 2:1 ligand to Cu(II) salt yielded the following unique solids: Cu(IPA)₂X₂(X=ClO₄⁻, BF₄⁻ and NO₃⁻) and Cu(IPA)X₂(X=Cl, Br). Characterization has been accomplished primarily by IR, electronic and ESR measurements of the solid state. IPA bonds as a bidentate ligand via its N-oxide oxygen and amine nitrogen in all of the complexes. Anion coordination occurs in the halogen complexes and the nitrate ions appear to be bound to Cu(II) as monodentate ligands in Cu(IPA)₂(NO₃)₂.

Me₃GeOS(O₂)CH₃ and Me₃GeOS(O)₂CF₃ have been prepared and characterised by their ¹H, ¹³C, ¹⁹F NMR, IR, Raman and mass spectra.

A theoretical and experimental study of the diffusion processes in complex-formation in ion exchangers has been made. The study is based on diffusion-type equations expressing the laws of material balance for the counterions and a co-ion. These equations are complemented by the conditions of electroneutrality and absence of any electric current. In particular, the approximate solutions of the equations suggest that during the initial stages of particle conversion, the degree of conversion depends on the input concentration and is proportional to √(t), the effective diffusion being controlled by the individual diffusion coefficients for the counterions. The exact solution of the problem, for varying relations between the individual diffusion coefficient has been obtained numerically by using computers. The principles thus found have been verified experimentally for the MeM exchange in a carboxylic cation exchanger and for MeMe exchange in a complex formation vinylpyridine cation exchanger, respectively. The experimental data agree with the theoretical deductions.