Thermal decomposition of some rare earth metal cupferrates and neocupferrates

The thermal decomposition of the eupferrates and neocupferrates of europium, terbium, dysprosium, holmium, erbium, and ytterbium was studied on the thermobalance. The metal chelates possessed poor thermal stability as well as a pronounced tendency to Coprecipitate reagent. The minimum oxide level temperatures for the metal cupferrates were : Eu, 570°; Tb, 540°; Dy, 550°; Ho, 610°; Er, 550° and Yb, 520°. The minimum oxide level temperatures for the metal neocupferrates were: Eu, 560°; Tb 565°; Dy, 540°; Ho,445°; Er, 530°; and Yb, 485°.     

Isomerization of n-hexane over Pt/NH4NaY zeolite

Isomerization of n-hexane over Pt/NH₄NaY follows the reaction scheme k₁, k₂, k_c linearly increase with increasing ammonia exchange degree in the zeolite and no significant changes in selectivity occur. During activation Al is partially removed from the lattice framework with the formation of HAlNaY.

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- Pt/NH₄NaY . k₁, k₂ k_c , . Al HAlNaY.

     

The thermal dissociation of the [Co(NH3)6]Cl3 and [Co(NH3)6]Br3 complexes in vacuo

The thermal dissociation of the complexes, [Co(NH₃)₆]X₃(X^?=Cl, Br), was studied in vacuo using the techniques of thermogravimetry, evolved gas analysis and mass spectrometric analysis. It was found that the reaction stoichiometry was identical to that previously determined in air but that the type of intermediate compounds formed were different. The dissociation occurred by the reactions:

     

4- und 5-Nitro-benzo[c]thiophen: Reaktionen mit CC-Dienophilen. Synthese von funktionalisierten und anellierten 7-Thia-bicyclo[2.2.1]heptenen — Struktur und Reaktivität voniso-anellierten Systemen mit 4nπ- und (4n+2)π-Elektronen, 19. Mitt.

Summary 4- and 5-nitro-benzo[c]thiophenes react as heterocyclic dienes with N-substituted maleic imides. [4+2] cycloaddition gives rise to the formation ofendo, exo configuratedDiels-Alder adducts. This efficient transformation can be utilized for the synthesis of benzo-annelated 7-thiabicyclo[2.2.1]heptenes. Their spectroscopic data are reported and compared with those of the [4 + 2] adducts of isoelectronic 4-(5)-nitro-2-tert-butyl-2H-isoindoles.

     

Acidity of SiO2, SiO2?Al2O3 and γ-Al2O3 supports and supported molybdena catalysts

Acidity of SiO₂, -Al₂O₃ and SiO₂–Al₂O₃ supports and supported Mo-catalysts in oxidized and reduced state are characterized by IR-spectroscopic and gravimetric pyridine (py) adsorption measurements. Differences in surface acidities are interpreted as results of differences in chemical compositions, molybdena-support interactions and molybdena dispersities.

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SiO₂, -Al₂O₃ SiO₂–Al₂O₃, Mo -- . , .

     

The thermal dissociation of sodium hexanitrocobaltate(III)

The stoichiometry of the thermal decomposition reaction of Na₃[Co(NO₂)₆] was studied by TG, DTA and mass spectrometric analysis.

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Zusammenfassung Es wurde über die Stöchiometrie der thermischen Zersetzung von Na₃[Co(NO₂)₆] berichtet auf Grund von TG, DTA und massenspektrometrischen Untersuchungen.

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Résumé On a examiné la décomposition thermique de Na₃[Co(NO₂)₆] de point de vue stoichiométrique par les méthodes ATG, ATD et spectrométrie de masse.

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Na₃[Co(NO₂)₆] , - .

     

Does the strain hardening modulus of glassy polymers scale with the flow stress?

Using a generic coarse‐grained bead‐spring model, Hoy and Robbins reproduced important experimental observations on strain hardening, specifically the generally observed Gaussian strain hardening response and its dependence on network density and temperature. Moreover, their simulation results showed that the strain hardening response at different strain rates collapses to a single curve when scaled to the value of the flow stress, a phenomenon that has not yet been verified experimentally. In the present study, the proposed scaling law is experimentally investigated on a variety of polymer glasses: poly(methyl methacrylate), poly(phenylene ether), polycarbonate, polystyrene, and poly(ethylene terephthalate)‐glycol. For these polymers, true stress–strain curves in uniaxial compression were collected over a range of strain rates and temperatures and scaled to the flow stress. It was found that, generally, the curves do not collapse on a mastercurve. In all cases, the strain hardening modulus is observed to increase linearly, but not proportionally to the flow stress. The experimental data, therefore, unambiguously demonstrate that the proposed scaling law does not apply within the range of temperature and strain rate covered in this study. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2475–2481, 2008     

The thermolysis of zirconium precipitates : Salts of organic acids

The thermal decomposition of the zirconium salts of phthalic, phenoxyacetic, cinnamic, diphenic, p-bromornandclic, benzilic, m-crcsoxyacetic, salicylic and bcnzoic acids and 8-quinolinol were studied on the thermobalancc. The precipitates exhibited varying degrees of stability with the first weight losses occurring in the temperature range of 45° to 160°. After decomposition through various intermediates, the oxide (ZrO₂) levels were obtained between 500° to 790°.     

PIGE and PIXE analyses of pentasil type boroaluminosilicates

The elemental composition of various synthetic crystalline sodium-boroaluminosilicates, especially the Al content and the silicon to aluminium bulk ratio, were determined by means of the combination of PIGE (Proton-Induced Gamma-Ray Emission Spectrometry) and PIXE (Proton-Induced X-Ray Emission Spectrometry). Light elements (B, O, Na, Al) were determined by means of gamma-ray emission. Proton-induced X-ray emission provided information on heavy elements present down to impurities. The Si/Al ratios, which mainly determine the catalytic and adsorptive properties of the zeolites, are compared with those obtained with other methods (EPMA, H₂O sorption capacity) and show good agreement.