51V NMR studies of a system vanadium pentoxide-potassium pyrosulfate

Two states of pentavalent vanadium in the system K₂S₂O₇–V₂O₅ have been found by the⁵¹V NMR method. For state 1 a polynuclear structure with greater distorted local environment compared with V₂O₅ is retained. For state 2 the nearest environment of vanadium differs significantly from V₂O₅, and is probably characterized by the higher ionic nature of the vanadium-oxygen bond.

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⁵¹V K₂S₂O₇–V₂O₅ . V₂O₅. , V₂O₅ , , -.

     

Hydrogenation of CO on thoria supported group VIII (Pd, Pt, Ir) metal catalysts

Comparative studies of the transformation of CO/H₂ mixtures on Pd supported (MgO, Al₂O₃, ThO₂) catalysts reveal the promoting effect of thoria, particularly towards hydrocarbon products.

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CO/H₂ Pd MgO, Al₂O₃ ThO₂ ThO₂, .

     

Catalytic properties of plantinized polycyanogens

The effect of various inorganic polymers on the catalytic activity and selectivity of platinum in the hydrogenation of 4-chloronitrobenzene and dinitrotoluene has been studied. Platinized iron-containing polycyanogens are less active but more selective catalysts for the hydrogenation of 4-chloronitrobenzene than Pt/C or Pt/BaSO₄.

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4- . , , , 4-, Pt/C Pt/BaSO₄.

     

A Thermal study of the precipitates formed in ammonia neutralization of acidic solutions of dissolved phlogopite

The precipitates containing mainly iron, aluminium and magnesium hydroxides, obtained from phlogopite dissolved in nitric acid by means of the neutralization procedure with ammonia, have been investigated by thermal analysis (TG, DTG and DTA). According to the present study, which is part of a larger investigation into the chemical utilization of Finnish mica minerals, the formation of solid solutions between iron and aluminium hydroxides in silt increases with an increasing neutralization temperature. Nitrogen exists mainly in the form of nitrate in silts, and magnesium forms mixed hydroxides with aluminium, which causes a separation between the iron hydroxide and magnesium aluminium hydroxide phases.

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Zusammenfassung Die von in Salpetersäure gelöstem Phlogopit durch Neutralisierung mit Ammoniak erhaltenen, hauptsächlich Eisen-, Aluminium- und Magnesiumhydroxid enthaltenden Niederschläge wurden thermoanalytisch (TG, DTG und DTA) untersucht. In der vorliegenden Arbeit, die Teil einer grossangelegten Untersuchung zur chemischen Nutzung finnischer Glimmermineralien ist, wird gezeigt, dass die Bildung fester Lösungen von Eisen- und Aluminiumhydroxiden in Schluff mit zunehmender Neutralisationstemperatur ansteigt. Stickstoff kommt in Schluff hauptsächlich in Form von Nitraten vor, und Magnesium bildet Mischhydroxide mit Aluminium, was eine Trennung der Eisenhydroxidphase von der Magnesium-Aluminium-Hydroxidphase bewirkt.

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, , , . . , , . , , , , .

     

Study of nitric oxide interaction with the Pt(100) surface by electron energy loss spectroscopy

The adsorption and dissociation of nitric oxide on the Pt(100) surface have been studied using Electron Energy Loss Spectroscopy.

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Pt(100).

     

Kinetic studies of ozonation of polyhydric alcohols

Kinetic studies of the oxidation of polyhydric alcohols by ozone-oxygen mixtures in aqueous solutions at 284–302 K indicate that the second-order effective rate constantk decreases with increasing substrate concentration.

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- 284–302 . , .

     

Isothermal dimensional changes of some dental materials

The isothermal dimensional changes of four types of dental amalgams during the setting and for the next 24 hours after condensation have been studied by means of a Heraeus TA 500 thermal analysis system. The four types of dental amalgams were the lathe-cut conventional lowcopper amalgam (Amalcap), the spherical conventional low-copper amalgam (Spheralloy), the ternary unicomposition high-copper amalgam (Sybralloy) and the admixed high-copper (Dispersalloy) amalgam.The dimensional changes of the four types of amalgams are explained on the basis of their particle sizes and shapes and their constitutions.

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Zusammenfassung Mittels eines Heraeus TA 500 Thermoanalysensystemes wurden isotherme Größenveränderungen von Dentalamalgamen während des Setting und der 24 Stunden nach der Kondensation untersucht. Die Größenveränderungen der vier Amalgamgrundtypen (am Beispiel von Amalcap, Spheralloy, Sybralloy und Dispersalloy) wurden auf der Grundlage ihrer Teilchengröße und -form sowie auf der Grundlage ihrer Zusammensetzung erklärt.

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500 24 . : (), (), () ( ). , .

     

A bifunctional stopcock-winch device in cells for infrared investigations of solids

A simple glass device is described acting as stopcock and winch at the same time. The device is especially suitable for the dislocation of solid sample holders in IR cells.

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, . .

     

Decomposition of N2O over CuxMg1?xAl2O4 catalysts

The results show that there is not difference between the catalytic activities of two series of Cu_xMg_1–xAl₂O₄ catalysts, despite a small but significant difference in cation distribution. The activity is mainly affected by the presence of CuO.

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, , , , - Cu_XMg_1–XAl₂O₄. CuO.

     

Catalytic mechanism of the reaction between N(4S) nitrogen atoms and sodium azide

Catalytic effect of transition metal oxides on the reaction of monatomic nitrogen with sodium azide has been experimentally established. The maximum effect is exerted by metal oxides with d³ configuration. Absorption of nitrogen atoms by reactive mixtures is accompanied by the complete compensation for the spins of unpaired d-electrons. A catalytic mechanism accounting for the formation of intermediate between d-metal ion and nitrogen atom is suggested.

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. —d³. d-. , d- .

     

Catalytic and acidic properties of different metal-zeolite catalysts

Catalytic and acidic properties of bifunctional catalysts containing faujasite, superhigh-silica zeolite and mordenite have been studied in isomerization of C₈-alkylaromatic hydrocarbons.

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C₈ , , - .

     

Specificity of hydrogen adsorption on chromia-supported platinum group metal catalysts

Hydrogen adsorption on chromia supported Pd, Rh and Pt was studied under various pretreatment conditions. The reduction temperature influences strongly the hydrogen uptake for all these metals. Platinum supported on chromia shows an unusually high hydrogen adsorption stoichiometry.

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Pd, Rh Pt, Cr₂O₃, . , . Cr₂O₃ .

     

Infrared spectra of nitric oxide adsorbed on photoreduced V/SiO2 catalyst

Studies of the IR spectra of surface species produced via NO adsorption on selectively photoreduced V/SiO₂ catalysts indicate that at low coverages NO is adsorbed on V³⁺ ions to form strongly bonded mononitrosyl species V³⁺...... NO. With increasing NO coverage, V³⁺ is oxidized to V⁴⁺, which is accompanied by the appearance of gaseous N₂O and weak adsorption of NO on V⁴⁺.

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- , NO V/SiO₂ . , V³⁺ NO V³⁺... NO. V³⁺ V⁴⁺, N₂O NO V⁴⁺.

     

Trends in the high-temperature heat capacities of ternary chalcopyrite semiconductors

The anharmonic contribution to the heat capacity of any chalcopyrite semiconductor A^IB^IIIC ₂ ^VI or A^IIB^IVC ₂ ^V is evaluated. It is shown that the degree of lattice anharmonicity decreases with increasing atomic weight of the constituent atoms of the compounds, and there is no essential difference in the degree of lattice anharmonicity of the two groups of compounds. Except for CdGeAs₂, the trend in the Grüneisen constants is the same.

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Zusammenfassung Der anharmonische Beitrag zur Wärmekapazität verschiedener Halbleiterverbindungen A^IB^IIIC ₂ ^VI und A^IIB^IVC ₂ ^V vom Chalkopyrit-Typ wird bestimmt. Es wird gezeigt, dass die Gitteranharmonizität mit steigender relativer Atommasse der Bestandteile der Verbindungen abnimmt und dass keine wesentlichen Unterschiede in der Gitteranharmonizität beider Gruppen von Verbindungen bestehen. Der Trend der Grüneisen-Konstanten ist der gleiche, ausgenommen bei CdGeAs₂.

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^IIII ₂ ^{VI IIIV} ₂ ^V . , , , . , CdGeAs₂.

     

Widening the possibilities of the kinetic method of freezing radicals

A new version of the freezing unit is proposed which permits to accumulate radicals outside of the apparatus. After that, the collector is separated from the reactor and placed into the ESR spectrometer resonator. The new construction sharply increases the efficiency of operation.

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, ye , . .

     

Ausbrennen von Kohlenstoffhaltigen,in den Ziegelrohstoff Eingepressten Stoffen

Zusammenfassung Die Kinetik der Ausbrennung organischer Stoffe im Ziegelscherben wird verfolgt und erläutert. Die Möglichkeiten der Beeinflussung des energetischen Aufwandes unter Nutzung moderner analytischer Methoden sind festzustellen. Bei einem diffusen Ausbrennen ist die Dichte und Durchlässigkeit des Scherbens massgebend. Praktische Anwendungsmöglichkeiten verschiedener auszubrennender Stoffe in unterschiedlichen Rohstoffen der Ziegelindustrie.

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The kinetics of burn-out of organic materials in bricks has been followed and explained. It is to establish that using new analytical methods the energy consumption can be influenced. The diffuse burn-out is determined by the density and permeability of bricks. There is a possibility for practical use of the results in the brick-industry with the different compounds to be burnt out from various raw materials.

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$ . , . . .

     

Nature of the active component of copper-zinc-aluminium catalyst for methanol synthesis

Comparative studies of the catalytic properties and thermal stability of a copper-zinc-aluminium catalyst and its components have revealed that the catalytic activity is determined by a solid solution of copper and aluminium in zinc oxide containing OH^– and CO ₃ ^2– groups in its anion skeleton. The presence of aluminium in the solid solution ensures the increase of the catalyst thermal stability in the reaction medium.

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-- , , OH^– CO ₃ ^2– -. .

     

The thermal decomposition of phosphorus iodides

The thermal decomposition of crystalline PI₃ and P₂I₄ in nitrogen and oxygen is reported. The oxidation of PI₃ leads mainly to the formation of phosphorus pentoxide and iodine together with P_xI polymeric species as a minor product. The decomposition of the polymeric species P₃I₂O₆ in oxygen and nitrogen follows a two-stage route which precludes its involvement in the oxidation of P₂I₄.

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Zusammenfassung Es wurde die thermische Zersetzung von kristallinem PI₃ und P₂I₄ in Stickstoff und Sauerstoff untersucht. Die Oxydation von PI₃ führt zur Bildung von Phosphorpentoxyd und Jod mit wenig Polymeren der Zusammensetzung P_xI. Die Zersetzung der Polymeren P₃I₂O₄ in Sauerstoff und Stickstoff erfolgt in zwei Stufen, die eine Beteiligung in der Oxydation von P₂I₄ ausschließen.

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Résumé On décrit la décomposition thermique, dans l'azote et dans l'oxygène, de PI₃ et de P₂I₂ cristallins. L'oxydation de PI₃ conduit principalement à la formation d'iode et de pentoxyde de phosphore, avec de petites quantités de P_xI de type polymère. La décomposition de l'espèce polymère P₃I₂O₆, dans l'oxygène et dans l'azote, s'effectue suivant un processus en deux étapes excluant sa participation à l'oxydation de P₂I₄.

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I₃ P₂I₄ . I₃, , , — — _xI . ₃I₂₆ , ₂I₄.

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The author is indebted to Mrs. I. M. Walker for practical assistance with the thermoanalysis studies.     

Nonisothermal kinetics of zinc oxide nonstoichiometrization

The results obtained by studying zinc oxide non-stoichiometrization are presented. The kinetic parameters values under nonisothermal conditions were calculated too. Both the nonstoichiometric zinc oxide composition and the kinetic parameter values are depending on the generating substances.

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Zusammenfassung Die Ergebnisse der Untersuchungen der Nichtstöchiometrisierung von Zinkoxid werden vorgeführt.Die Werte der kinetischen Parameter unter nicht-isothermen Bedingungen wurden eben falls berechnet.Sowohl die nichtstöchiometrische Zusammensetzung des Zinkoxids als auch die Werte der kinetischen Parameter hängen von der das Phänomen auslösenden Substanz ab.

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Résumé On présente les résultats d'une étude sur la formation d'oxyde de zinc non-stchiométrique. Les valeurs des paramètres cinétiques en conditions non-isothermes sont égale ment calculées. La composition de l'oxyde de zinc non-stchiométrique ainsi que les valeurs des paramètres cinétiques dépendent du composé de départ.

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, , . .

     

A thermoanalytical study on some compounds of Zr(IV) with azopyrazolonic derivatives

Thermoanalytical data on six reagents and on their compounds with Zr(IV) are reported. Except for H acid, all reagents were azopyrazolonic derivatives obtained by synthesis. The purpose of this study was to obtain data on the thermal stabilities of the reagents and their zirconium compounds, and to establish the reagent: zirconium: water combination ratio.

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Zusammenfassung Thermoanalytische Daten von 6 Reagenzien und deren Verbindungen mit Zr(IV) werden mitgeteilt. Außer H-Säure waren alle Reagenzien durch Synthese erhaltene Azopyrazolon-Derivate. Zweck der Untersuchung war, Daten über die thermische Stabilität dieser Reagenzien und ihrer Zirkonverbindungen zu erhalten und das Verhältnis Reagens: Zirkon: Wasser festzustellen.

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. , , - . , : : .