Thermal Decomposition in Systems of Acid Zn(II), Co(II), and Ni(II) Maleates with the Formation of Metallic Nanoparticles

Russian Journal of Physical Chemistry A - Conditions of synthesis are optimized and XRD and thermoanalytical studies are performed for normal maleate [Zn(H2O)2(C4H2O4)] and acid maleate...     

Regularities of thermolysis for the Fe(II), Co(II), and Ni(II) salts of maleic and ortho-phthalic acids with the formation of metal/polymer composites

Russian Journal of Coordination Chemistry - Regularities of the thermolysis of acidic salts of unsaturated (maleic) [M(H2O)4(C4H3O4)2] and aromatic (ortho-phthalic) [M(H2O)6](C8H5O4)2 (M = Fe(II),...     

Thermal transformations of the supramolecular compound of cucurbit[8]uril with cobalt(III) complex {<Emphasis Type="Italic">trans</Emphasis>-[Co(en)<Subscript>2</Subscript>Cl<Subscript>2</Subscript>]@CB[8]}Cl·17 H<Subscript>2</Subscript>O

The thermal decomposition of hydrated cucurbit[8]uril C₄₈H₄₈N₃₂O₁₆·20H₂O (CB[8]) and the inclusion compound of cucurbit[8]uril with cobalt(III) complex {trans-[Co(en)₂Cl₂]@CB[8]}Cl·17 H₂O was studied in the inert atmosphere by TG, TM, and DSC methods. The dehydration of (C₄₈H₄₈N₃₂O₁₆)·20H₂O (at 320–390 K), and the decomposition of cucurbituril itself (at 620–720 K) are accompanied by a decrease in the sample volume. The inclusion compound loses water molecules at 320–380 K; dehydration is accompanied by an increase in the sample volume. The decomposition (pyrolisis) of the anhydrous compound takes place at 620–720 K; the decomposition is forestalled by a continued increase in the sample volume with an endothermic peak (490–600 K), and only the mass loss (620–720 K) is accompanied by a decrease in the sample volume. The included guest complex does not lose amines until the decomposition process is complete; the previously observed increase in the sample volume is explained by the expansion of cavitand molecules due to a distortion of the included [Co(en)₂Cl₂]⁺ complex on heating.     

The study of the thermal dissociation processes of compounds of the type MoO2(C6H5CONHO)2.nA

Thermal dissociation processes of compounds with the composition MoO₂(C₆H₅CONHO)₂.nA (A-polar organic solvent: alcohols, aldehydes, ketones, organic acids) were investigated. Kinetics of dissociation was studied in a flow reactor, the values of activation energy and preexponential factor were calculated. The influence of a solvent nature, of the length of included molecules and of the type of crystalline lattice was studied. The sequence of kinetic stability was obtained. It corresponds to the sequence of solvent activity with respect to H-binding up with the complex. For the series of alcohols nonmonotonous dependence of kinetic parameters on the length of chain (with the division into two groups: with even and oddn) was obtained. For all the compounds studied a compensation relationship is observed (lgA=aE+b).

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Zusammenfassung Es wurden thermische DissoziationsvorgÄnge von Verbindungen der Zusammensetzung MoO₂(C₆H₅CONHO)₂ nA (mitA=polares organisches Lösungsmittel: Alkohole, Aldehyde, Ketone, organische SÄuren) untersucht. Die Dissoziationskinetik wurde in einem Durchlaufreaktor untersucht, die Werte für Aktivierungsenergie und prÄexponentiellen Faktor berechnet. Es wurde weiterhin der Einflu\ von der Art des Lösungsmittels, von der LÄnge der beteiligten Moleküle und vom Kristallgittertyp untersucht sowie eine Reihenfolge bezüglich der kinetischen StabilitÄt ermittelt. Diese stimmt mit der Reihenfolge der LösungsmittelaktivitÄt bezüglich der H-Bindung zum Komplex überein. Für die Alkoholreihen (zwei Reihen: mit geradem bzw. ungerademn) wurde keine sich monoton mit der analogen Reihe verÄndernde AbhÄngigkeit der kinetischen Parameter von der KettenlÄnge beobachtet. Für alle untersuchten Verbindungen wurde eine Kompensationsgleichung (lgA=aE+b) beobachtet.

     

Generalization of results of the computational modeling of streamline flow of a parachute by an undisturbed high-speed flow of gas using the method of large particles

On the basis of analysis of the numerical solution of the problem of aerodynamics of a parachute using the method of large particles, a simple analytical method of determining the pressure gradient on the canopy and the resistance coefficient of the parachute in a high-speed flow of gas is given. The results of computations coincide well with the experimental ones.Translated from Dinamicheskie Sistemy, No. 9, pp. 81–86, 1990.