An analysis of the possible causes of apparent compensation effects when investigating a substance under varying experimental conditions

The major causes leading to the apparent compensation effect (lgA=aE+b) at the thermal decomposition of one and the same substance in a series of experimental conditions (varying of the mass of the sample, of the heating rate, of disperseness, and at different distances from the equilibrium) were discussed. It was found that the appearance of a compensation effect at the study of the thermal decomposition of one and the same substance demonstrates the incorrect setup of the experiment, resulting in erroneous values calculated for the kinetic parameters.

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Zusammenfassung Die Hauptursachen, welche zum scheinbaren Kompensationseffekt (lgA=aE+b) der thermischen Zersetzung ein und derselben Substanz führen, wurden unter verschiedenen Versuchsbedingungen untersucht: unter Änderung der Probenmasse, der Aufheizgeschwindigkeit, der Dispersität und der Entfernung vom Gleichgewicht. Es wurde festgestellt, daß das Auftreten eines Kompensationseffekts bei der Untersuchung der thermischen Zersetzung ein und derselben Substanz auf die unrichtige Durchführung des Experiments hinweist, die zur Berechnung falscher Werte der kinetischen Parameter führt.

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Résumé On a étudié les causes principales de l'effet de compensation apparent (lgA=aE+ +b) lors de la décomposition thermique de la même substance dans différentes conditions expérimentales, en faisant varier notamment la masse du prélèvement, la vitesse du chauffage, la dispersion et l'écart à l'équilibre. On a trouvé que l'apparition d'un effet de compensation lors de l'étude de la décomposition thermique de la même substance résultait de l'exécution incorrecte de l'expérience qui mène à des valeurs fausses lors du calcul des paramètres cinétiques.

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, (lg A=aE+b) : , , , . , , .

     

Reaction of gaseous hydrogen fluoride with aluminium and its compounds

The reaction of metallic aluminium surfaces, aluminium oxides, hydrated oxides and sulphate with gaseous anhydrous hydrogen fluoride was studied at 470°C and pressures between 10 and 100 torr. The complementary analytical techniques of X-ray induced photoelectron spectra, X-ray and electron diffraction, and electron microscopy were used for identifying the (frequently unexpected) products.     

Simple method for the preparation of 1-oxo-1-chlorophospholenes

Conclusions A new and simple method has been found for the synthesis of 1-oxo-1-chlorophospholenes by the reaction of phosphorus trichloride, a diene, and an oxygen-donor compound, the best of which is acetone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1847–1848, August, 1972.     

Synthesen in der Naphthalinreihe: Methoxylierte Tetralone und Naphthole

Ohne ZusammenfassungHerrn Prof. Dr.A. Franke in aufrichtiger Verehrung zum 80. Geburtstag gewidmet.     

Reactions of 4-(o-carboranyl)pyrylium salts with nucleophilic agents. Synthesis of nitrogen heterocycles with an o-carboranyl substituent

Nitrogen heterocycles, viz., pyridines, pyridinium salts, diazepine, and pyrazoles, with an o-carboranyl substituent were obtained by reaction of 4-(o-carboranyl)-pyrylium perchlorates with nitrogen-containig nucleophilic agents, viz., ammonia, primary amines, hydrazine, and phenylhydrazine. Opening of the pyrylium ring without involvement of the carborane ring occurs under the influence of bases.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 454–458, April, 1981.     

Low temperature magnetic susceptibility and exchange interaction in Cs3Cr2Cl9

Magnetic susceptibility of Cs₃Cr₂Cl₉ as a single crystal is studied in the temperature range 4.2–77 K. A maximum is obtained at 25 ± 1 K. These experimental data are interpreted by considering the isotropic exchange interaction between two spin quadruplets. The exchange constant J is found to be equal to - 13 cm^?1.