DTA analysis of water emanation from the system CuCl2 - KCl

Mixtures of CuCl₂ and KCl in molar ratios of Cu to K of 0.5 to 2.0 were obtained at room temperature, and then subjected to DTA analysis in the temperature range 293–473 K. A number of endothermic effects were observed, the extents of these depending on the molar ratio of Cu to K in the mixture.

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Zusammenfassung Bei Zimmertemperatur wurden Gemische aus CuCl₂ und KC1 mit einem Cu:K Molverhältnis zwischen 0.5 und 2.0 erhalten und dann im Temperaturbereich 293–473 K einer DTA-Analyse unterzogen. Es konnte eine Anzahl von endothermen Effekten beobachtet werden, deren Größe eine Funktion des Cu:K Molverhältnisses im Gemisch ist.

     

Copolymers dispersions designed to shaping of ceramic materials

Journal of Thermal Analysis and Calorimetry - To study the effect of ionic liquids (ILs) of the microstructure on the surface of the coal, four ILs ([Emim][BF4], [Bmim][BF4], [Bmim][NO3], and...     

DTA analysis of the system carrier-CuCl2, KCl. part I

DTA analysis of carrier-CuCl₂, KCl catalysts with total active salt contents of from 17.68 to 33.27%, and with CuK molar ratios of from 0.691 to 0.922, revealed a number of endothermic processes within the temperature range 293–773 K. The extents of these processes depended on the total salt content and the CuK molar ratio. The influence of the carrier on the active phase constitution was observed. >

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Zusammenfassung Die DTA-Anlyse von Trägerkatalysatoren mit CuCl₂KCl mit einem Aktivsalzgesamtgehalt von 17.68 bis 33.27% und einem molaren Verhältnis (Cu zu K) von 0.691 bis 0.922 zeigte, daß beim Erhitzen der Katalysatoren im Temperaturbereich von 293–773 K eine Reihe endothermer Vorgänge ablaufen. Die Größe dieser endothermen Effekte ist abhängig vom Aktivsalzgesamtgehalt und vom molaren Verhältnis CuK. Der Einfluß des Trägermateriales auf die Konstitution der aktiven Phase wurde untersucht.

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The author is grateful to Prof. Dr. hab. Zdzislaw Czarny for discussions and advice.     

Observations on the solid system CuCl2-KCl in the temperature range 293–673 K

The system CuCl₂-KCl was obtained at room temperature by evaporation of its aqueous solutions, and observations were made on its behaviour at room atmosphere and in an atmosphere poor in water. With the Boetius apparatus, mixtures of CuCl₂ and KC1 were observed up to 673 K. The observations explain the unstable character of the solid system CuCl₂-KCl during its instrumental analysis in air atmosphere, and also explain the phenomenon of melting of the solid system CuCl₂-KCl with molar ratios of Cu to K of from 0.5 to 2.0. Conclusions were drawn on the constitution of the mixtures in the solid state, and also partially in the melt.

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Zusammenfassung Durch Verdampfen wäßriger Lösungen wurden bei Raumtemperatur CuCl₂ — KCl Systeme erhalten, deren Verhalten in normaler Raumatmosphäre und in wasserarmer Atmosphäre beobachtet wurde. Mittels eines Boetius Gerätes wurden Mischungen aus CuCl₂ und KCl bis zu einer Temperatur von 673 K beobachtet. Die Untersuchungen erklären den unstabilen Charakter des CuCl₂ — KCl Feststoffsystemes bei der instrumenteilen Analyse in normaler Luftatmosphäre und erklären auch Die Erscheinung des Schmelzens des CuCl₂ — KCl Feststoffsystemes mit einem Cu zu K Molverhältnis von 0,5 zu 2,0. Es wurden Schlußfolgerungen über die Konstitution der Gemische im festen und teilweise auch im geschmolzenen Zustand gezogen.

     

Electrocatalytic properties of platinum nanocenters electrogenerated at ultra-trace levels within zeolitic phosphododecatungstate cesium salt matrices

A unique preparation method of obtaining stable composite film (with ultra-low platinum content) highly active towards oxygen reduction and hydrogen oxidation is presented here. The matrix for platinum centers consists of high-surface-area zeolite-type acidic salt of cesium phosphododecatungstate (Cs_2.5H_0.5PW₁₂O₄₀) admixed with carbon (Vulcan XC-72) carriers. Platinum nanoparticles were deposited on the working electrode modified with matrix via corrosion of platinum counter electrode during cyclic voltammetry experiment conducted in acid electrolyte containing chloride ions. The results obtained from rotating disk voltammetry revealed that the composite film containing Pt nanoparticles at very low loadings (on the level of 2–5 μg cm^?2) demonstrated remarkable electrocatalytic activity towards both oxygen reduction and hydrogen oxidation, particularly, when compared to the performance of the Cs_2.5H_0.5PW₁₂O₄₀-free system (i.e., containing only Vulcan support) prepared and examined under analogous conditions. The phenomenon should be primarily ascribed to the mesoporous nature of the matrix enabling immobilization and stabilization of small catalytic nanoparticles (1–2 nm diameters) inside the pores as well as to high surface acidity of the polyoxometalate-based salt providing proton-rich environment at the electrocatalytic interface.     

DTA analysis of the system carrier-CuCl2, KCl Part II

Catalysts of the type carrier-CuCl₂, KCl differing in the temperature at which they were obtained and after the ethene oxychlorination process were analyzed thermogravimetrically. Catalysts after the oxychlorination process differed in total salt content and in the molar ratio of CuCl₂ to KCl. A number of endothermic processes were observed in the DTA curves, the extents of these varying with change in the temperature at which the catalysts were obtained and in the catalyst composition.

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Zusammenfassung Bei verschiedenen Temperaturen hergestellte Katalysatoren des Types Carrier-CuCl₂,KCl wurden nach dem Ethylen-Oxychlorierungsprozeß thermogravimetrisch untersucht. Die Katalysatoren unterschieden sich nach dem Oxychlorierungsprozeß sowohl in ihrem absoluten Salzgehalt als auch im Molverhältnis CuCl₂ zu KCl. Anhand der DTA-Kurven wurde eine Anzahl endothermer Vorgänge beobachtet, deren Ausmaß von der Katalysatorenzusammensetzung sowie davon abhängt, bei welcher Temperatur der Katalysator hergestellt wurde.

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The author thanks Prof. dr hab. Zdzislaw Czarny for discussions and advice.     

Changes in ion composition in the liquid system CuCl2-KCl,investigated by thermogravimetry

CuCl₂-KCl mixtures were annealed at 603 K and thermogravimetrically analysed after cooling to room temperature. The mixtures differed in the molar ratio Cu/K and in the duration of heating at 603 K. The constitutions of the ions, the reactions between them and the mechanisms of their decomposition in the melt are proposed, as are the constitutions of the active centres in the oxychlorination process.     

Influence of additives on the dta curves of the system Cu1Cl2 - KCl

Mixtures of CuCl and KCl containing the additives MgCl₂, NaCl or CsCl were heated at 473 K in air atmosphere, and then subjected to DTA analysis in the temperature range 293–773 K. The molar ratio of Cu to K in the mixtures varied from 0.5 to 1.0. The influence of the additives on the DTA pictures of the CuCl₂-KCl system was observed.

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Zusammenfassung Gemische aus CuCl₂ und KC1 wurden mit Zusätzen von MgC₂, NaCl oder CsCl bei 473 K in Luft erhitzt und dann im Temperaturbereich 293–773 K einer DTA-Untersuchung unterzogen. Das Molverhältnis Cu:K variierte in den Gemischen zwischen 0.5 und 1.0. Es wurde der Einfluß der Zusätze auf den Verlauf der DTA-Kurven des Systemes CuCl₂-KCl untersucht.

     

Thermogravimetric investigation of thermal decomposition of copper(II) complexes with methylpyrido[2,3-d]imidazole derivatives

Solid-state complexes with the formulae CuL _x X₂·nH₂O, wereL=2-methyl-, 5-methyl-, or 7-methylpyrido[2,3-d]imidazole,X=NO ₃ ^– or Cl^–,x=2 or 3, andn=1 or 2, were subjected to thermogravimetric analyses. The kinetic parameters were calculated according to the Coats-Redfern method. Reactions paths are proposed and their agreement with the data obtained from TG curves is checked.The authors thank Dr. W. Surga for XRD analyses, and Dr. B. Kowalczyk and Dr. M. Czerwinski from the Pedagogical University in Czestochowa for providing access to the computer application allowing calculation of the kinetic parameters.