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- . .     

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.     

Salt effects in the reaction between IrCl62? and MnEDTA2?

The oxidation of MnEDTA^2–. (EDTA=ethylenediaminetetra-acetate) by hexachloroiridate(IV) has been studied in concentrated electrolyte solutions at 298 K. The estimation of the activity coefficients of the species from the Stokes-Robinson hydration theory indicates that the observed salt effects have their origin in a greater destabilization of the initial state with respect to the transition state when increasing salt concentration. MnEDTA^2– (EDTA= ) (IV) . -, , .     

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. , , . , , .     

On the mechanism of water dissociation on the surface of Al2O3. Quantum-chemical calculations

Quantum-chemical calculations of clusters modelling adsorption complexes on the -Al₂O₃ surface have been used to evaluate two points of view on the mechanism of surface dissociation of water molecules on this oxide. The calculations show that this process involves interaction of water molecules with basic surface oxygen atoms rather than with Lewis acid sites.- , -Al₂O₃, H₂O . , .     

Alkylation of p-substituted phenols by heteropoly acids

Liquid-phase alkylation of p-tert-butylphenol (TBP) and p-cresol by olefins and benzyl chloride in the presence of solid heteropoly acids (HPA) H₃PW₁₂O₄₀ and 25% H₃PW₁₂O₄₀/SiO₂ at 100–150°C provides high yields of mono- and disubstituted products. HPAs are more active than H₂SO₄, easily separated from the reaction mixture and can be used repeatedly. -- () - () H₃PW₁₂O₄₀ 25% H₃PW₁₂O₄₀/SiO₂ 100–150°C - - . , H₂SO₄, - - .     

Kinetic studies of Pt/Al2O3 catalyst pellets with nonuniform activity

Catalysts with nonuniform distribution of the catalytically active component (Pt) over their porous support (Al₂O₃) have been studied. A nonuniform activity distribution changes not only the reaction rate but also the kinetics can be different on these catalysts.

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(Pt) (Al₂O₃). , , .

     

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.     

Kinetics of perborate oxidation of quinol

The perborate oxidation of quinol in aqueous acetic acid is first order with respect to perborate, zero order with respect to quinol, and first order with respect to H⁺. The oxidation is faster than H₂O₂ oxidation. Breakdown of protonated perboric acid is suggested as the rate-limiting step.

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, H⁺. . , , , .

     

Ethylene hydroformylation over a nafion-supported rhodium catalyst

Ethylene hydroformylation over a Nafion-supported rhodium catalyst has been studied under atmospheric pressure in the temperature range of 100–135 °C, using the transient response method.

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, , 100–135°C, .

     

Kinetics and deuterium isotope effects of proton transfer reactions of di (4-nitrophenyl) methane with alkoxide bases in appropriate alcohols

The second-order rate constants, activation parameters and primary deuterium isotope effects are reported for the proton-transfer reactions from di (4-nitrophenyl)-methane to sodium ethoxide, iso-propoxide and t-butoxide in appropriate alcohols. The mechanism for the reaction is discussed. , -(4-) , - . .     

Determination of basic sites on the surface of metal oxide catalysts by desorption of benzoic acid

A method has been developed for the determination of the concentration of basic sites on white and deeply colored solid porous materials, which is based on the displacement of adsorbed benzoic acid by acetic acid. The determination is rapid and gives results comparable with those obrained by the titration with benzoic acid using thymolphthalein as indicator.

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. . , , , .

     

Chemisorptive characterization of Mn2+ cation effects on fused iron-catalysts

Volumetric and pulse chemisorptions of carbon monoxide (CO) have been developed to characterize effects of Mn²⁺ cations on an industrial doubly promoted fused iron catalyst. Addition of Mn²⁺ cations induces an increase in Fe dispersity, Fe electronic density and stability of the Mn²⁺-containing iron catalyst, where the same increase is observed by XPS and SEM. These effects explain why the activity of Mn²⁺-containing iron catalysts is improved. Mn²⁺ , . Mn²⁺ Fe, Fe , XPS SEM. . Mn²⁺ .