Phase equilibrium diagram for the tin(II) iodide-copper(I) iodide system

The phase diagram of the SnI₂-CuI system was determined by the method of thermal analysis. No intermediates were found. It is suggested that limiting solid solutions of SnI₂ in-CuI,-CuI and-CuI, respectively, are formed. The eutectic point parameters (32.7 mol% CuI, 270.4 ±0.1 °C) and those of two invariant points (64.0 mol% CuI, 385.3 ±0.5 °C and 61.5 mol% CuI, 366.6±0.2 °C), corresponding to the equilibria+liquid and+liquid , respectively, were determined.Mittels Thermoanalyse wurde das Phasendiagramm SnI₂-CuI bestimmt. Es konnten keine Intermediäre gefunden werden. Es scheint, daß Grenzmischkristalle von Shl2 und-CuI,-CuI,-CuI gebildet werden. Es wurden ein Eutektikum (32,7 mol% CuI, 270,4 ± 0,1 °C) und zwei den Gleichgewichten+Flüssigkeit und+Flüssigkeit entsprechende invariante Punkte (64,0 mol% CuI, 385,3±0,5 °C und 61,5 mol% CuI, 366,6±0,2 °C) gefunden. SnI₂-CuI, . , , -CuI,-CuI Cul. (32,7 % CuI, 270,4±0,1°) (64,0 % Cul, 385,3 ±0,5° 61,5 % CuI, 366,6±0,2°), + + .

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The present work was carried out within the framework of contract CPBP 01.15.     

Studies of the interaction of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) with imidazole in acetonitrile

The reaction of DDQ with imidazole in acetonitrile is a two-step process. The formation of an anion radical is followed by slow substitution of Cl atoms to form diaminobenzoquinone. Kinetics of the second step is reported. . - Cl CN- . .     

Oscillatory reactions of sakhalin oil oxidation

After light irradiation of oil films on water surface the autoxidation process has been found to be of nonsteady auto-oscillatory character, which can be observed in rate oscillations of O₂ absorption. Also recorded have been intensity oscillations of the EPR signal from the radical counter added into an oil sample. Complex dynamics of autoxidation can be due to an autocatalytic process involving the participation of peroxides accumulated in oil during photooxidation., , , , O₂. , , . , , .     

Abnormally high fractal dimension of silica surfaces measured by adsorption of aliphatic alcohols

Factors leading to abnormally high fractal dimension D of silica surfaces measured by adsorption of aliphatic alcohols have been analyzed. , D .     

Thermodynamic studies of clathrate hydrates

Thermodynamic studies of clathrate hydrates, mainly of structures I and II, are considered in this review which is based on 147 references. There are two main subjects. The first is the host lattice energy and the guest-host interaction energy, both of these quantities being related to the enthalpy of dissociation and composition of the hydrates. The second subject concerns orientational ordering phenomena occurring in both host and guest, as reflected in the low temperature heat capacity. The classical theoretical treatment of clathrate formation has been reconsidered on the basis of recent experimental results. Particular emphasis has been given to orientational ordering since this topic is undoubtedly central to clarifying the nature of clathrate hydrates.Ausgehend von 147 Literaturangaben wurden in diesem Review thermodynamische Untersuchungen von Klathrathydraten hauptsächlich der Struktur I und II betrachtet. Es gibt zwei Hauptaugenmerke. Als erstes die Wirtsgitterenergie und die Gast-Wirt-Wechselwirkungsenergie, beide bezogen auf die Dissoziationsenthalpie und die Bildungsenthalpie der Hydrate. Das zweite Hauptaugenmerk betrifft Orientierungs-Konditionierungserscheinungen sowohl in Wirt als auch Gast, wie in den Wärmekapazitäten bei niedrigen Temperaturen widergespiegelt wird. Auf der Basis jüngster experimenteller Ergebnisse wurde die klassische theoretische Betrachtung über die Bildung von Klathraten überprüft. Der Orientierung-Konditionierung wurde besonderer Nachdruck verliehen, da dies zweifellos eine entscheidende Rolle bei der Klärung der Natur der Klathrathydrate spielt. 147 I II. . «» « — », . «» « », . . , .

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Contribution No. 155 from the Chemical Thermodynamics Laboratory.     

Heat evolution during hydration of Ca4(Al6O12)(SO4)

The hydration of the sulphatealuminate phase Ca₄(Al₆O₁₂)(SO₄) at room temperature was observed by means of differential calorimetry and quantitative X-ray diffraction phase analysis in situ. The results were used to evaluate the kinetics of the hydration process and to explain the causes of the exothermic effects: an initial surface reaction, the formation of a highly dispersed system, and the crystallization of monosulphate, Ca₄(Al₂O₆)(SO₄) · 12H₂O, and gibbsite, Al(OH)₃. The experiments showed an increase in efficiency of hydration with a higher mass ratio of water to solid phase (from 143.8 kJ/mol) atw/s=1 to 170.0 kJ/mol atw/s=10).

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Zusammenfassung Die Hydration der Sulfat-aluminat-Phase Ca₄(Al₆O₁₂)(SO₄) bei Zimmertemperatur wurde mittels Differentialkalorimetrie und quantitativer in-situ-Röntgenbeugungs-Phasenanalyse verfolgt. Ein vergleich der Ergebnisse erlaubte die Kinetik des Hydratationsprozesses abzuschätzen und die Ursache der exothermen Effekte zu klären: Anfängliche Oberflächenreaktion, Bildung eines hochdispersen Systems, Kristallisation von Monosulfathydrat Ca₄(Al₂O₆)SO₄·12H₂O und Hydrargillit Al(OH)₃. Die Versuche zeigten eine Zunahme der Hydratationseffektivität mit steigendem Verhältnis Wasser: Feststoff (w/s) von 143,8 kJ mol^–1 beiw/s=1 auf 170,0 kJ mol^–1 beiw/s=10.

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in situ ₄(l₆)(S₄). , , ₄(l₂₆)(S₄) · 122 l()₃. : 143,8 ^–1 1 170,0 · ^–1 10.

     

Electronic spectrum and thermal decomposition of nickel(II) complex with bis(N-γ-pyridyl-4-phenylbenzamide-hydrazone)

The unit cell parameters and the space group of the investigated compound were determined by means of X-ray diffraction.Analysis of the diffusion-reflection spectra of the crystalline powder and the absorption spectra of its alcoholic solutions permitted identification and quantitative characterization of the absorption bands of the crystalline complex of NiL₂(ClO₄)₂·3H₂O.Application of differential-thermal analysis allowed determination of the mechanism of thermal decomposition of the compound. From these measurements, the expected configuration of the basic molecule was verified, involving determination of the number of non-coordinated water molecules.

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Zusammenfassung Mittels Röntgendiffraktionsmethoden wurden Gitterzellenkonstanten sowie die Raumgruppe der untersuchten Verbindung bestimmt. Durch Analyse der erhaltenen Diffusions-Reflexionsspektren von kristallinem Pulver und des Absorptionsspektrums einer alkoholischen Lösung der Verbindung war es möglich, die Absorptionsbanden des Kristallkomplexes NiL₂(ClO₄)₂·3H₂O zu identifizieren und quantitativ zu charakterisieren. Anwendung von Differentialthermoanalyse ermöglicht die Bestimmung des Mechanismus der Zersetzungsreaktion der Verbindung. Durch diese Messungen, einschliesslich der Bestimmung der Anzahl nichtkoordinierter Wassermoleküle, wurde die erwartete Konfiguration des Grundmoleküles überprüft.

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NiL₂(ClO₄)₂·₂, L-N-- -4- . L-N---4- . , , . . , .

     

Calorimetric study of the BrO3?/Ce4+/cyclohexanone and BrO3?/Ce4+/cyclopentanone oscillating systems

The heat output (Q) during the induction period of a Belousov-Zhabotinskii oscillating reaction usually evolves at a constant rate /6/; we observe in the BrO ₃ ^– /Ce⁴⁺/Cyclohexanone system a sudden change in the slope of the function Q=f(t), which corresponds to the beginning of the quasistationary phase /3/.

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(Q) - ; BrO ₃ ^– /Ce⁺⁴/ Q=f(t), .

     

Kinetics of methanol synthesis in the presence of low-temperature catalyst

The kinetics of methanol synthesis performed in a flow circulation installation in the presence of low-temperature copperzinc-aluminium catalyst has been investigated. The application of a power kinetic equation describing the surface chemical interaction on an exponentially inhomogeneous surface is established. The effect of the volume rate and the temperature is studied and the presence of a compensation effect is proved. A possibility of determination of the temperature and the volume rate, under which conditions the side-reactions do not affect the main one, is shown on the basis of the kinetic investigations.

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-- - . - - . . , .

     

Thermal dissociation of basic aluminium ammonium sulfate in vacuum

A mathematical model of the thermal decomposition of basic aluminium ammonium sulfate has been developed. The construction of the model consisted in simulation of TG and DTG curves, with the use of kinetic parameters identified on the basis of results obtained in measurements of the rate of thermal dissociation of the compound under isothermal and non-isothermal conditions.

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Zusammenfassung Es wurde das mathematische Modell fur thermische Zersetzung des basischen Ammoniumaluminiumsulfats bearbeitet. Die Struktur des Modells bestand in der Nachbildung von thermogravimetrischen Kurven TG, DTG mittels der kinetischen Parameter, die auf Grund der isothermen und der nichtisothermen Ergebnisse der Untersuchungen nach der Dissoziationsgeschwindigkeit von Verbindungen identifiziert wurden.

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Résumé Un modèle mathématique décrivant la décomposition thermique du sulfate basique d'aluminium et d'ammonium est présenté.La méthode consiste à simuler les courbes thermogravimétriques TG et TGD à l'aide des paramètres cinétiques identifiés sur la base des résultats des déterminations isothermes et nonisothermes de la vitesse de la dissociation du composé.

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. , , .

     

Kinetics and mechanism of the ligand substitution reaction of aquodiethylenetriaminepentaacetatoruthenate (III) in aqueous solution

The kinetics of ligand substitution reactions of [Ru(H₂dtpa) (H₂O)] (2) (H₂dtpa=diprotonated diethylenetriaminepentaacetic acid) were studied as a function of ligand (L) concentration, pH (2.5–8.0) and temperature (30–45 °C) at 0.2 M ionic strength. The equilibrium constants for the formation of mixed ligand complex [Ru^III(dtpa) (L)] (L=2-mercaptopyrimidine, cysteine) and the distribution of various species in solution in the pH range of 2.5–8.0 were computed from potentiometric results. [Ru(H₂dtpa) (H₂O)] ( H₂dtpa= ) , pH (2,5–8,0) (30–45°C) 0,2 M. [Ru^III(dtpa) (L)] ( L=2-, ) pH=2,5–8,0.     

Study of hydroisomerization of n-hexane on natural mordenite catalyst

A mordenite-containing rock sample from the Tokaj Mountains (Hungary) and its various forms modified by chemical treatment have been tested for catalytic properties during isomerization of n-hexane. Addition of Pt to the catalyst leads to a sharp decrease in the rate of cracking and in the rate of deactivation and this results in a catalyst of high selectivity for hexane isomers.

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(), , , , -. Pt , .

     

Modifying action of carbon dioxide in catalytic oxidation of ethylene on silver

Carbon dioxide exerts a strong inhibitory effect on oxygen adsorption and complete oxidation of ethylene on silver but has little effect on the rate of ethylene oxidation to ethylene oxide.

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.

     

Testing the photocatalytic activity of cyanogen-and thiocyanogen-based inorganic polymers

The photocatalytic properties of some cyanogen-and thiocyanogen-based inorganic polymers, such as paracyanogens containing different metals (Hg, Ag, Cu), polythiocyanogens of different iodine contents, polycyanogen and poly (cyanogenthiocyanate), have been tested in two systems. Cu-containing paracyanogen and the iodine-poor polythiocyanogens catalyze the photoreduction of methylviologen under visible light, furthermore the Cu-containing paracyanogen catalyzes the photoreduction of water to hydrogen under UV irradiation.

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, , , , (Hg, Ag, Cu), , (), . , , , , , , -.

     

Effect of acio properties of the alumina surface on the formation of chlorides during its interaction with CCl4

IR spectroscopy was employed to study acid properties of a series of alumina samples different in the phase composition and in the porous structure. The comparison of the surface acidity with the data on the quantitative formation of Cl^– during the interaction of CCl₄ with alumina indicates that the extent of chlorination of the samples tends to increase with increasing the surface acidity.

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- , . Cl^– CCl₄ , .