X-ray studies of supported copper-aluminium catalysts

Structural peculiarities of the formation of copper-aluminium catalysts at copper concentrations <10 wt% and calcination temperatures of 573–1173 K have been studied.

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<10% . 573–1173°K.

     

Line widths of the 3800 Å singlet transitions in crystalline anthracene

The theory of resonance coupling of Frenkel excitons and phonons is extended to two molecules per unit cell. Intra- and inter-band scattering for the two Davydov components can thus be dealt with on the same footing. Restrictions to nearest neighbour interactions have been removed. Application to anthracene shows that the contribution of librational phonons to the scattering is approximately one hundred times larger than that of translational phonons. The widths of the anthracene components are shown to fit the calculated coupling and known phonon frequencies satisfactorily.     

Alkyl–oxygen bond formation in the mass spectra of α-chloromethyl aryl sulphones

When subjected to electron-impact, chloromethyl aryl sulphones (II, X = Cl) fragment predominantly by the loss of CH₂Cl from the molecular ion followed by the loss of SO₂ and in most cases the appropriate metastable peaks are present to confirm the transitions. In addition, alkyl–oxygen bond formation in the molecular ion was revealed by the presence of prominent peaks corresponding to the [R? ?-SO]⁺ ions. In most spectra no evidence for aryl–oxygen bond formation could be found and thus the presence of the chlorine atom was able to effectively reverse the direction of skeletal rearrangement reported for aryl methyl sulphones.     

Phase diagram and X-ray diffraction analysis of the acrylic acid–acrylamide system

The phase diagram of the acrylic acid–acrylamide system as determined by DTA and the supporting x-ray diffraction data are presented. This diagram shows that the system forms a 1 : 1 addition compound which decomposes above 0°C. There is also one eutectic point at a 67 mole-% acrylic acid composition.     

A viscometric study of poly(methyl methacrylate) in 2-alkoxyethanols

θ-Conditions, the temperature coefficient of unperturbed dimensions of the macromolecules and the thermodynamic interaction parameters ψ and κ were determined for solutions of poly(methyl methacrylate) in 2-alkoxyethanols (methoxy, ethoxy and butoxy). The results for this series of solvents fit the data reported for other solvents and dln $\text{r}{}_0{}^2\text{/}\text{d}\text{T = 2.6 × 10}{}^{\mathrm{?3}}\text{K}{}^{\mathrm{?1}}$. The dependence of parameters ψ and κ exhibited deviations from the theoretical dependence, mainly near the limiting value ψ = 0.5.     

Water-soluble copolymers. XXV. Ion-binding studies of N-substituted acrylamide copolymers using potentiometric and spectroscopic methods

Spectroscopic and potentiometric methods have been used to study the ionic properties of several N-substituted acrylamide copolymers that display unusual ion-binding character. The ionic groups and the amide groups (both on the same repeating unit and on adjacent acrylamide units) in the copolymers are found to chelate calcium ions. The stabilizing effect of this amide chelation is found to be dependent on copolymer composition. A model is proposed to explain the unusual binding behavior of the acrylamide polymers. This involves the formation of an intramonomer chelate or one with neighboring acrylamide units that prevent precipitation of the polymers.     

Thermodynamische Untersuchungen im System Gold—Cadmium, 2. Mitt.

Liquidus and solidus curves of the -AuCd phase were determined byDTA measurements. -AuCd has a congruent melting point of 629.5°C at 47 at% Cd with no signs of other minima or maxima in the liquidus curve between 43 and 51 at% Cd. Liquid and solid Au–Cd alloys were investigated by theemf method between 40 and 90 at% Cd and 653–973 K. A consistent set of integral thermodynamic data for liquid and for solid alloys of the entire Au–Cd system were calculated at 1000 and at 700K, resp., using values taken from the literature. Partial molar entropies of Cd of solid -AuCd and of liquid alloys in the same concentration range were compared and discussed with respect to ordering phenomena in solid and liquid alloys.

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Mit 3 Abbildungen     

Is laser-ablation-ICP-MS an alternative to solution analysis of solid samples?

The basic obstacles for the general use of laser-ablation(LA)-ICP-MS in analytical laboratories are connected with its reproducibility and calibration. A mathematical relation deduced from the correlation function of the analytical signals allows the estimation of the number of craters needed for representative analyses. The procedure was applied to different samples such as manganese crusts and soils. The ion intensities of the major elements in the manganese crusts and nodules were used as internal standards, improving relative standard deviations by factors between 2 and 3. Selected samples of wood and manganese crusts were analyzed by LA-ICP-MS and the results compared with those obtained by solution ICP-MS. The agreement of the values is within the 95% confidence limits. Powdered reference materials and, in the case of wood analysis, cellulose doped with standard solutions were used for the calibration.     

Sequential electroelution and mass spectroscopic identification of intact sodium dodecyl sulfate-proteins labeled with 5(6)-carboxyfluorescein-N-hydroxysuccinimide ester

A gel electrophoresis apparatus capable of scanning the migration path fluorometrically and of computer-directed electroelution of bands was applied to the mass spectrometric identification of sequentially electroeluted 5(6)-carboxyfluorescein-N-hydrosuccinimide ester (FLUOS)-labeled sodium dodedyl sulfate (SDS)-proteins. The masses of four electroeluted SDS-proteins under study determined by matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) spectrometry are changed by 1% due to their reaction with FLUOS in a 1:5 molar ratio of protein:label, allowing for the identification of the labeled intact proteins on the basis of mass. More importantly, the partial (10 or 50%) derivatization of proteins with FLUOS does not preclude their tryptic hydrolysis, and identification of the protein on the basis of the mass spectrometric analysis of its tryptic peptides. Potentially, the procedure allows for the automated mass spectrometric identification of SDS-proteins globally labeled with FLUOS and electrophoretically separated, without need for any gel sectioning.     

Reactions of esters of tetracoordinated phosphorus acids with nucleophilic reagents in highly organized media

Characteristic features of reactions involving esters of phosphorus-containing acids in highly organized media (micelles, liquid crystals, vesicles, and emulsions) are surveyed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 298–312, February, 1996.