Catalytic isomerization of phenylcyclohexane in the presence of aluminium chloride

Intermolecular migration accompanied by deuterium atom rearrangement between the cycloalkyl fragment carbon atoms has been found during the interaction of phenylcyclohexane-1d₁ in benzene-¹⁴C with aluminium chloride. Relative rates of these conversions have been estimated. The reaction mechanism is discussed.

---

, -1d₁ -¹⁴C , . .

     

Methane synthesis from CO/H2O mixture on supported nickel catalysts, I. Influence of the support on the catalytic properties

The behavior of some supported Ni catalysts for methane synthesis from CO and steam in correlation with the specific metal-support interactions is discussed.

---

CO . .

     

Measurement of the specific heat and heat of decomposition of a polymer composite to high temperatures

The specific heat and heat of decomposition of a glass-filled phenolformaldehyde (phenolic) resin have been determined from experimental data obtained using a simultaneous thermal analyzer capable of operation to 1500 C. The measurements were conducted on powdered samples of the polymer to temperatures of approximately 1050 C at a rate of 20 deg min^–1 in an argon atmosphere. Both the mass loss and energetics were measured for the virgin component of the material, while only the energetics were measured for the char component. The combination of these data was used to calculate the specific heat of the virgin, char, and decomposing material, as well as the heat of decomposition. Also, in order to establish the accuracy of the instrument, the specific heat of pyroceram 9606 was measured and compared to previously published values.

---

Zusammenfassung Die spezifische Wärme und die Zersetzungswärme eines glasgefüllten Phenol-Formaldehyd-Harzes wurden aus experimentellen Daten bestimmt, die mittels eines simultanen ThermoanalyseGerätes für Arbeiten bis 1500 C gewonnen wurden. Die Messungen wurden an gepulverten Polymerproben bis zu Temperaturen von 1050 C mit einer Aufheizgeschwindigkeit von 20 K min^–1 in Argonatmosphäre durchgeführt. Massenverlust und Energieänderungen wurden für das jungfräuliche Material gemessen, die Energieänderung auch für das verkohlte Material. Zur Prüfung der Messgenauigkeit des Geräts wurde die spezifische Wärmekapazität von Pyroceram 9606 gemessen und mit früher publizierten Daten verglichen.

---

, 1500, () . 1050 20/. , — . , , . 9606, .

---

---

On sabbatical leave from the University of Rhode Island, Kingston, Rhode Island 02881 U.S.A.     

Utilization of the affine transformation of thermoanalytical curves for the determination of kinetic parameters

A method is suggested for the affine transformation of thermoanalytical curves, by means of which their comparison with one another becomes feasible. It is demonstrated that the results obtained by the traditional methods of non-isothermal kinetics depend on the heating rate, whereas the results attained by affine transformation are independent of the heating rate. They are consistent with the results obtained by Merzhanov's dmethod, which is also a non-aprioristic method.

---

Zusammenfassung Eine Methode zur Affintransformierung thermoanalytischer Kurven wird vorgeschlagen, wodurch ihr Vergleich miteinandere rmöglicht wird. Es wird gezeigt, daß die durch traditionelle Methoden der nicht-isothermen Kinetik erhaltenen Ergebnisse von der Aufheizgeschwindigkeit abhängig sind, während die durch Affintransformierung erhaltenen von der Aufheizgeschwindigkeit unabhängig sind. Sie sind in Übereinstimmung mit den nach der Methode von Merzhanov erhaltenen Ergebnissen, die ebenfalls eine nicht-aprioristische Methode ist.

---

Résumé On propose une méthode pour la transformation affine des courbes d'analyse thermique, qui permet leur comparaison. On montre que les résultats obtenus par les méthodes traditionnelles de cinétique non-isotherme dépendent de la vitesse du chauffage, tandis que les résultats obtenus par la transformation affine n'en dépendent pas. Ils sont en accord avec les résultats de la méthode de Merzhanov.

---

, . , , , , , , . , , .

     

Thermodynamics and thermochemistry of kinetic (real) phase diagrams involving solids

A theoretical analysis of the formation of materials with metastable microstructures under non-ideal and highly non-equilibrium conditions is presented.

---

Zusammenfassung Es wird eine theoretische Untersuchung der Bildung von Stoffen mit metastabilen MikroStrukturen unter nichtidealen Bedingungen weitab vom Gleichgewicht dargelegt.

---

.

     

Nature of the adsorption centers of oxide catalysts and the direction of propylene conversion

According to the analysis of spectral data on adsorbed propylene forms, an attempt has been made to establish a relationship between the nature of olefin adsorption center, the adsorbed form during precatalysis and the direction of conversion.

---

, .

     

Differential scanning calorimetry of chloroquine sulphate exposed to sun,heat and ultraviolet radiation

Chloroquine sulphate, like the phosphate, is an antimalarial formulation widely used in the tropics. The stability of such formulations is therefore of interest in the combat against malaria. A DSC study has been made of the effects of exposure to the sun, heat and UV radiation on the stability of chloroquine sulphate, similarly as performed earlier for chloroquine phosphate. When freshly recrystallized from a water-acetone mixture, chloroquine sulphate exhibits two endothermic peaks, at 169.4° and 204.7°, for the expulsion of crystal water (one molecule) and for the melting process, respectively. The exposure of chloroquine sulphate to the sun, heat and UV radiation leads to splitting of the peak for melting.

---

Zusammenfassung Chloroquine-Sulfat ist ebenso wie das entsprechende Phosphatderivat ein in den Tropen weitverbreitet angewandtes Antimalaria-Präparat. Die Stabilität dieses Präparates hat damit Bedeutung für die Malariabekämpfung. Die vorliegende Arbeit ist eine Erweiterung einer Untersuchung über den Effekt der Einwirkung.von Sonne, Hitze und UV-Strahlen auf die Stabilität von Chloroquine-Phosphat auf Chloroquine-Sulfat. Aus Wasser-Aceton-Mischungen frisch kristallisiertes Chloroquine-Sulfat zeigt zwei endotherme Peaks bei 169,4 und 204,7 °C, die durch Abgabe von Kristallwasser (ein Molekül) bzw. durch den Schmelzvorgang bedingt sind. Wird Chloroquine-Sulfat der Sonne, Wärme oder UV-Licht ausgesetzt, so wird der dem Schmelzvorgang zuzuscheibende Peak aufgespalten.

---

, -, , . . , . , , 169,4 204,7°, , , . , .

     

Precipitation of iron catalysts for the Fischer-Tropsch synthesis

The batch Fischer-Tropsch wise precipitation of iron catalysts for the synthesis in the pH range of 4.60 to 7.91 is described in detail. Each step of the precipitation has been controlled by measurements of the relevant parameters to produce definite catalysts. Factors influencing the reproducibility are shortly discussed.

---

- pH=4,60–7,91. . , .

     

Investigation of thermal degradation of polymers containing chlorine by thermogravimetry

The thermal degradation of chlorine-containing polymers used in a rubber technology has been investigated in a nitrogen atmosphere. The characteristics of degradation have been compared on the basis of thermogravimetry, carbon residues and chlorine elimination. The observed structure-dependent differences in degradation of the investigated polymers are discussed.

---

Zusammenfassung Die thermische Zersetzung von in der Kautschuk-Technologie verwendeten chlorhaltigen Polymeren wurde unter Stickstoff untersucht.Die Charakteristika der Zersetzung durch die Thermogravimetrie, Kohlenrückstand und Chlorabspaltung wurden verglichen. Die in der Zersetzung der untersuchten Polymere in Abhängigkeit von ihrer Struktur beobachteten Unterschiede wurden diskutiert.

---

Résumé On a étudié, en atmosphère d'azote, la dégradation thermique des polymères contenant du chlore, utilisés dans la technologie du caoutchouc.On a comparé les caractéristiques de la dégradation par thermogravimétrie, formation d'un résidu de carbone et élimination du chlore. On discute les différences observées dans la dégradation des polymères étudiés suivant leur structure.

---

, . . .

     

Investigation of surface phenomena on solid catalysts by thermogravimetry

Thermogravimetry was applied to the investigation of the phenomena of adsorption, chemisorption, desorption and surface reactions on solid catalysts. The measurements were carried out with 13 NaX and NaY type zeolites and with silica gels treated with sodium hydroxide, in the presence of cumene and methanol. On the basis of the quantitative results it is possible to give an interpretation of surface phenomena and to establish the existence of various active centres on the surface of the catalysts.

---

Zusammenfassung Adsorptions-, Chemisorptions- und Desorptionserscheinungen, sowie Oberflächenreaktionen an festen Katalysatoren wurden thermogravimetrisch untersucht. Die Messungen wurden an Zeoliten der Typen 13 NaX und NaY und an mit Natriumhydroxid behandelten Silikagelen in Gegenwart von Cumol und Methanol durchgeführt. Aufgrund der quantitativen Ergebnisse war es möglich, die Oberflächenerscheinungen zu deuten und das Vorhandensein von verschiedenen aktiven Zentren an der Katalysatoroberfläche nachzuweisen.

---

Résumé On a appliqué la méthode thermogravimétrique à l'étude des phénomènes d'adsorption, de chemisorption et de désorption ainsi qu'aux réactions de surface sur des catalyseurs solides. Les mesures ont été effectuées sur zéolites de type 13 NaX et NaY et sur des silicagels traités par la soude en présence de cumène et de méthanol. Des résultats quantitatifs permettent de donner une interprétation des phénomènes de surface et d'établir l'existence de divers centres actifs à la surface des catalyseurs.

---

, , , . , , , , . 13 NaX NaY , . .

---

---

The authors express their gratitude to Prof. S. Malinowski for help and discussion and to Mr. W. Dziklinski for his technical help.     

The lability of carbon monoxide adsorbed on rhodium

Carbon monoxide which is retained by a rhodium surface after heating to 573 K exchanges with gas phase carbon monoxide at 293 K. The retained species is postulated as *–C=O–*.

---

, 573 , 293 . *–C=O–*.

     

On the occurrence of competitive mechanisms in the transformation of butadiene into maleic anhydride with air on MoO3?TiO2 catalysts

Unusual variations of selectivity are observed in the catalytic oxidation of butadiene on MoO₃–TiO₂ catalysts. A maximum of selectivity in furan and maleic anhydride is obtained at 400°C, since the oxidation of crotonaldehyde, dihydrofuran and furan are selective at all temperatures. Competitive oxidation of furan and crotonaldehyde proved that the aldehyde cannot be the unique intermediate for furan and maleic anhydride formation. Two mechanisms, involving various adsorbed species of butadiene, occur depending on the temperature and explain the decrease of the selectivity below 400°C.

---

MoO₃–TiO₂ . 400°C, , . , . , , , 400°C.

     

Tracing of peroxy radicals in hexane cool flames

Stabilized hexane-air cool flames in a separately heated two-section reactor have been studied at T=480–770 K and P=30–63 kPa. ESR spectra of peroxy radicals were analyzed by the radical freezing technique and sonde sampling. Under these conditions high radical concentrations (>10¹⁴ cm^–3) are observed. With increasing pressure and temperature, the fraction of HO₂ radicals in the overall amount of radicals grows.

---

480–770 , 30–63 . . , (>10¹⁴cm^–3). , HO₂ .

     

Toluene disproportionation and coke formation over fluorided alumina and hydrogen-mordenite

Toluene transformation was investigated on a fluorided alumina and a protonic mordenite under hydrogen (0.8, 12 bar) and under nitrogen (12 bar). Hydrogen pressure considerably improves the catalytic stability of H-mordenite by inhibiting the formation of coke. Moreover, hydrogen eliminates part of the coke deposited by reaction under nitrogen, and regenerates the activity of the mordenite. On the contrary, hydrogen has no effect in the case of fluorided alumina. The particular behavior of the mordenite is attributed to its very strong acidity.

---

(0,8, 12 ) (12 ). -, . , , , . , - . .

     

Thermogravimetry. Fast methods for evaluation of kinetic parameters

The paper discusses three fast methods for determination of the reaction order, as follows: the single-point method proposed by Kissinger, Horowitz and Metzger, an original two-point method, and the three-point method suggested by a Gorbachev's paper. These methods cannot elucidate the reaction mechanism, but they can help in the rapid derivation of the apparent kinetic parametersn andE.

---

Zusammenfassung Es wurden drei Methoden zur Schnellbestimmung von Reaktionsordnungen ausgewertet: eine Einpunktmethode von Kissinger, Horowitz und Metzger, eine Zweipunktmethode und eine Dreipunktmethode nach einer Anregung von Gorbachev. Mittels dieser Methoden kann man zwar nicht den Reaktionsmechanismus bestimmen, wohl aber eine schnelle Bestimmung der kinetischen Scheinparametern undE durchführen.

---

: , , , , . , n .

     

Quantum chemical study of the stabilization process of faujasites

The CNDO/2 method is employed in the study of the energetics of the zeolite stabilization process in which skeletal Al atoms are replaced by amorphous Si. It is shown that such a process results in the stabilization of the zeolitic skeleton and that the stabilizing effect increases with decreasing Si: Al ratio as well as with the degree of hydration of the Al-cation formed.

---

/2 , Al Si. , Si:Al, Al.

     

Influence of lead on propane aromatization over Pt/ZSM5 catalysts

Aromatization of propane has been investigated over Pt-Pb/ZSM5. Addition of Pb decreases propane conversion with a corresponding increase in the aromatic selectivity. Hydrogenolysis reactions are inhibited by the presence of lead.

---

Pt–Pb/ZSM-5. Pb . .

     

Potentiometric titration of sorbed hydrogen on palladium carrier catalysts

A method of determination of adsorbed and absorbed hydrogen on palladium catalysts with carbon carriers is suggested and verified. The method allows H_ad and H_ab to be determined with an accuracy of about 10% using catalysts containing at least 5% Pd.

---

- . . . 10% , , - , 5% Pd.

     

Retarded solid state reactions

Reconstructive phase transitions and formation or decomposition reactions in the solid state exhibit in DTA-measurements a more or less great hysteresis between the temperatures from heating and cooling curves; at worst the reaction can be suppressed completely. By e.m.f.vs. T-measurements in appropriate galvanic cells for solid electrolytes equilibrium temperatures in the case of such kinetic hindrance can be determined and additionally the existence of metastable states can be proved.

---

Zusammenfassung Rekonstruktive Phasenumwandlungen sowie Bildungs- und Zersetzungsreaktionen im festen Zustand zeigen bei DTA-Messungen eine mehr oder minder große Hysteresis zwischen den aus Aufheiz- bzw. Abkühlkurven ermittelten Temperaturen; schlimmstenfalls kann die Festkörperreaktion völlig unterdrückt sein. Mißt man in geeigneten galvanischen Zellen für Festelektrolyte EMK-gegen-T-Kurven, so erhält man auch im Falle kinetischer Hemmungen Gleichgewichtstemperaturen und kann darüber hinaus das Vorliegen metastabiler Zustände nachweisen.

---

, : . .

---

---

We have to thank the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industry for supporting our work from the outset.     

Effect of free phosphine on the reactivity of phosphine-containing rhodium(I) complexes

The photolysis products of SO₂-pentane-NO mixtures are N₂O, H₂O and a compound designated as RNO. Kinetic data obtained by OC method confirm the previously proposed scheme of photolysis. Also studied was the photolysis of SO₂, NO and cyclohexane mixtures. From comparison of spectral characteristics of RNO and its analog 2-methyl-2-nitrosopropane, the probable structure of RNO is suggested.

---

SO₂--NO N₂O, H₂O , RNO. , , . SO₂ NO . RNO 2--2- RNO.