Studies of the composition and catalytic properties of supported catalysts prepared through halide-substituted titanium and zirconium benzyl complexes

Composition and catalytic properties in ethylene polymerization of supported systems prepared via the interaction of Ti(CH₂C₆H₅)₃X (X=F, Cl, Br) and Zr(CH₂C₆H₅)₂Cl₂ complexes with silica and alumina have been studied. Halide addition to benzyl complexes decreases the polymer molecular mass.

---

, Ti(CH₂C₆H₅)₃X (X=F, Cl, Br) Zr(CH₂C₆H₅)₂Cl₂ SiO₂ Al₂O₃. , .

     

Thermal decomposition of strontium hydroxide

The thermal behaviour of strontium hydroxide octahydrate was studied by thermal analysis, an X-ray diffraction technique and optical microscopy. Up to 210° this compound transforms to the hexahydrate and then to the monohydrate. Anhydrous strontium hydroxide crystallizes in the tetragonal system and a polymorphous transformation may occur at 480°. From 530° on it decomposes in three stages. Amorphous strontium oxide is obtained at 700°.

---

Zusammenfassung Das thermische Verhalten von Strontiumhydroxyd-Oktahydrat wurde röntgendiffraktometrisch, thermoanalytisch und durch optische Mikroskopie untersucht. Die Verbindung geht bis 210° in das Hex- und daraufhin ins Monohydrat über. Die Anhydroverbindung kristallisiert tetragonal. Bei 480° erfolgt eine polymorphe Umwandlung. Über 530° verläuft eine Dehydroxylation in drei Stufen. Amorphes Strontiumoxyd wurde bei 700° erhalten.

---

Résumé On a étudié le comportement thermique de l'hydroxyde de strontium octohydraté par analyse thermique, diffraction de rayons X et examen microscopique. Ce composé donne l'hexahydrate jusqu'à 210° puis le monohydrate. L'hydroxyde de strontium anhydre cristallise dans le système tétragonal et présente une transformation polymorphique à 480°. La déshydroxylation commence à 530° et s'effectue en 3 étapes. L'oxyde de strontium amorphe s'obtient à 700°.

---

, . 210° , . 480°. 530° . 700°.

     

Statistical analysis of enthalpy determination results relating to the dehydration process of CuSO4· 5H2O

Methods of variance analysis were utilized to select the conditions used in DSC studies of dehydration processes of various copper sulphate hydrates. The constant methodical errors were determined. Procedures were pointed out to increase the accuracy of DSC measurements in dehydration processes.

---

Zusammenfassung Methoden der Varianzanalyse werden angewandt, um die Auswahl der Bedingungen zur Untersuchung des Dehydratisierungsprozesses verschiedener Kupfersulfat-Hydrate mittels DSC zu treffen. Die konstanten methodischen Fehler wurden ermittelt. Es wird auf Verfahren zur Erhöhung der Genauigkeit von DSC-Messungen bei Dehydratisierungsprozessen hingewiesen.

---

. . - .

     

Silylation of porous glass supported platinum catalysts

Effect of silylation with hexamethyldisilazane on adsorption and catalytic properties of porous glass-supported platinum catalysts has been studied. Catalytic activity decreases markedly with an increase in surface coverage by trimethylsilyl groups for all the following reactions examined: hydrogenation of benzene, dehydrogenation of cyclohexane and dehydrocyclization of n-hexane.

---

, . , : , -.

     

Kinetic laws for dehydrogenation of cyclohexane over Pd/C catalysts

A kinetic equation for cyclohexane dehydrogenation at P_O=1.0 MPa has been obtained.

---

1,0 .

     

Novel evidence for the selective behaviour of tungsten carbide in liquid phase heterogeneous catalytic hydrogenation

Liquid (aqueous) phase catalytic hydrogenation of compounds containing two oxo-groups in -position (biacetyl, glyoxal, alloxan) was studied in the presence of tungsten carbide catalyst. It has been shown that only one of the oxo-groups is affected in the course of the process and is transformed into a >CH–OH group. Comparative studies carried out in the presence of platinum catalyst attest the selective behaviour of tungsten carbide.

---

- - (, , ). , >C=O >CH–OH, . .

     

Electrochemical model of monooxygenase

The monooxygenation of aniline by hemin, with oxygen activation by direct electron transfer from a cathode to the catalytically active center and direct participation of the reduced oxygen species in the reaction has been carried out.

---

.

     

Properties of template-free synthetic (B, Al) pentasil type zeolites

Template-free synthetic, boron-containing pentasil type zeolites exhibit structural and catalytic properties similar to those of SABO zeolites made in the presence of n-propylamine.

---

, , , SABO, -.

     

Support and mixing effect of an Fe2O3 catalyst for oxidative dehydrogenation of 1-butene

The support and mixing effects of Fe₂O₃ for the activity of 1-butene oxidative dehydrogenation were examined. Alumina and titania which were able to catalyze the isomerization of butene via an allyl intermediate, stimulated remarkably the formation of butadiene from butene when they were used as support or mixing component of Fe₂O₃ catalyst. Otherwise Fe₂O₃ supported on SO ₄ ^2– ion containing Al₂O₃ or TiO₂–Al₂O₃, which catalyze the isomerization via a cationic intermediate, is almost inactive for the formation of butadiene.

---

Fe₂O₃ 1-. , , , Fe₂O₃. , Fe₂O₃, Al₂O₃, SO ₄ ^–2 , TiO₂–Al₂O₃, , .

     

Thermal analysis of poly(methyl methacrylate)-copper composite

Thermal characteristics of the composites of poly(methyl methacrylate) and copper are reported, including the order of reaction and activation energy of the major second stage of pyrolysis. The randomly-distributed metal particles in the polymer matrix can form paths for heat transfer which determine the mechanism of thermal degradation.

---

Zusammenfassung Die thermischen Charakteristika der Verbindungen von Polymethylmethacrylat mit Kupfer werden zusammen mit der Reaktionsordnung und der Aktivierungsenergie der grösseren zweiten Stufe der Pyrolyse beschrieben. Die zufallsbestimmt verteilten Metallpartikel in der Polymermatrix können Wege des Wärmetransfers formen, welche den Mechanismus der thermischen Zersetzung bestimmen.

---

Résumé On décrit les caractéristiques thermiques de composites du polyméthylméthacrylate avec le cuivre, parmi lesquelles l'ordre de réaction et l'énergie d'activation de la seconde étape de la pyrolyse qui est la principale. Les particules du métal distribuées au hasard dans la matrice du polymère peuvent constituer des voies pour le transfert de chaleur qui déterminent le mécanisme de la dégradation thermique.

---

, . , .

     

Thermogravimetric study of dehydration of Ca(NO3)2 · CO(NH2)2 · 3 H2O under quasi-isothermal-quasi-isobaric conditions

Conventional thermoanalytical curves provide little information on the thermal decomposition of Ca(NO₃)₂ · CO(NH₂)₂ · 3 H₂O. In contrast from quasi-isothermal-quasi-isobaric thermogravimetric curves the mechanism can easily be interpreted. After the complex melts at 60°C, the solution formed is weight constant up to 135°C in the labyrinth crucible. The solution begins to boil at 135°C and gradually loses water, its boiling point increasing. The solution becomes saturated at 200°C. Thereafter, Ca(NO₃)₂ · CO(NH₂)₂ separates out while the boiling point does not change. After the departure of the water, the CO(NH₂)₂ immediately decomposes and Ca(NO₃)₂ remains.In an open crucible the above transformation is complicated by decomposition of typeAB _(s)=A _(s)+B _(g) solution evaporation drying of solid residue, surface crust formation, etc. In conventional thermoanalysis the latter processes accompany the above processes (melting-solution formation-loss of water during boiling) which hampers interpretation of the conventional curve.

---

Zusammenfassung Herkömmliche thermoanalytische Kurven liefern wenig Informationen über die thermische Zersetzung von Ca(NO₃)₂ · CO(NH₂)₂ · 3 H₂O. Quasi-isotherme/quasi-isobare thermogravimetrische Kurven dagegen ermöglichen leicht eine Interpretation des Mechanismus. Nach dem Schmelzen des Komplexes bei 60°C bleibt das Gewicht der Lösung im Labyrinthtiegel bis 135°C konstant. Die Lösung beginnt bei 135°C zu sieden und verliert zunehmend an Wasser, wobei der Siedepunkt ansteigt. Die Lösung erreicht den Sättigungspunkt bei 200°C. Danach scheidet sich Ca(NO₃)₂ · CO(NH₂)₂ ohne weitere Veränderung des Siedepunktes ab. Nach Entfernung des Wassers zersetzt sich das CO(NH₂)₂ sofort und Ca(NO₃)₂ bleibt zurück.In einem offenen Tiegel wird die obige Umwandlung durch Zersetzung des TypesAB _(s)= =A _(s)+B_(g), durch Verdampfung der Lösung, durch Trocknung des festen Rückstandes, durch Oberflächenverkrustung usw. kompliziert. Diese Prozesse begleiten bei der herkömmlichen Thermoanalyse die oben erwähnten Vorgänge (Schmelzen-Lösungsbildung-Wasserverlust durch Sieden), wodurch die Interpretation der herkömmlichen Kurven erschwert wird.

---

(N₃)₂·(N₂)₂·3 ₂O . , - , . 60° 135°. 135° . - 200°. , (N₃)₂ · (N₂)₂ . , . , AB_pac.=A_pac + B_pac., , , .. : — — , .

---

---

The authors are indebted to Prof. E. Bulewicz and Prof. E. Pungor for valuable discussions.They thank Mrs. M. Kiss and Miss I. Fábián for technical assistance.     

Steady state kinetic equation for SO2 oxidation on vanadium catalysts

From the analysis of the detailed reaction mechanism and taking into account vanadium complex formation processes, a steady state kinetic equation has been derived to describe experimental data in a wide range of reaction conditions.

---

, .

     

Studies of Cu?Ni supported catalysts for enantioselective hydrogenation

The effect of support content and composition of supported metal phase on the crystallite size, phase composition and catalytic properties of supported Ni and Cu–Ni catalysts has been investigated. It has been established that with increasing metal content, crystallite sizes and enantioselectivity increase. Copper added to Ni catalysts decreases metal phase dispersity and enantioselectivity.

---

, , - . , . є .

     

Influence of the preparation method on the pore spectrum of Pt?Cr/Al2O3 and Pt?Sn/Al2O3 catalysts

It is shown that, in contrast to classical impregnation methods, in bimetallic catalyst production the texture of the carrier is stabilized by introducing the promoting ion on the surface of Pt/Al₂O₃ with vapors of CrO₂Cl₂ or SnCl₄. This is shown by a relatively slower decrease of the specific area and the volume of the pores upon calcination.

---

, Pt/Al₂O₃- CrO₂Cl₂ SnCl₄ . .

     

ESR spin-trapping study of the radicals produced in the photochemical reaction of Cr, Mo, W hexacarbonyls with carbon tetrachloride

The effect of UV and visible light on the catalytic reaction has been investigated in the systems containing Cr, Mo and W hexacarbonyls, nitrone and nitroso type of spin-traps in carbon tetrachloride. Under these reaction conditions not only radical CCl ₃ ^. but also dialkyl-, diphenyl- and acyl-phenylnitroxides have been trapped.

---

, Cr, Mo W, . CCl ₃ ^. , , .

     

The application of thermoanalytical methods in the investigation of biological substances

The equilibria and thermodynamics of a number of naturally occuring isolated compounds (e.g. proteins, amino acids, carbohydrates) have recently been studied in several laboraties in different temperature ranges, and thermoanalytical methods have been used to study structural changes of biological materials, among them human tissues.In our investigations we succeeded in appling the derivatograph for the assay of glycosaminoglycans and for the characterization of the stability of crosslinked proteins in intact human and animal tissues. By means of this method age-related and pathological changes and repair reactions were studied in various connective and vascular tissues.Other temperature-dependent techniques (DSC, polarizing microscopy) were used successfully in another series of experiments. Alterations in the characteristic order-disorder transition temperatures of human serum lipoproteins could be demonstrated in pathological conditions; the altered physical structure of lipoproteins might give an additional explanation to the assumed mechanism of different metabolic disorders.

---

Zusammenfassung Die Gleichgewichte und die Thermodynamik einer Reihe von natürlich vorkommenden isolierten Verbindungen (z. B. Proteine, Aminosäuren, Kohlenhydrate) wurden in verschiedenen Laboratorien in verschiedenen Temperaturbereichen untersucht. Hierbei wurden thermoanalytische Methoden zum Studium der Strukturänderungen von biologischem Material, u. a. von menschlichem Gewebe, eingesetzt.In unseren Untersuchungen gelang es den Derivatographen zur Prüfung von Glycosaminoglycanen und zur Charakterisierung der Stabilität quervernetzter Proteine in intakten menschlichen und tierischen Geweben einzusetzen. Durch diese Methode wurden altersbedingte und pathologische Änderungen sowie Reaktionen zur Wiederherstellung in verschiedenen Binde und Vasculärgeweben studiert.Andere temperaturabhängige Techniken (DSC, Polarisationsmikroskopie) wurden in anderen Versuchsserien mit Erfolg eingesetzt.

---

, . , , , , . . , . .

---

---

Plenary lecture     

Liquid-phase hydrogenation on new AlPO4?SiO2 supported rhodium catalysts

The liquid-phase catalytic hydrogenation of various organic compounds was carried out using new rhodium catalysts supported on AlPO₄–SiO₂ (2080 wt. %) system, in methanol as solvent, under low hydrogen pressure (0.55 MPa) and at 293 K. Neither alkene isomerization nor hydrogenolysis products were detected in any of the cases.

---

AlPO₄–SiO₂ (2080 . %), , , (0,55 MPa) 293 . , .

     

Acetoxylation of olefins catalyzed by a palladium(II)-heteropolyacid system

The catalytic acetoxylation of ethylene and propylene occurs under the action of oxygen in the presence of Pd(II)+HPA-6, where HPA-6 is the heteropolyacid H₉PMo₆V₆O₄₀. In addition to the products of acetoxylation (alkenyl and allyl acetates), oxidation products (acetaldehyde and acetone) are also formed. The selectivity of acetoxylation increases upon the addition of NaOAc.

---

— — Pd(II)+-6, -6 H₉PMo₆V₆O₄₀. (- ) — . NaOAc.