Kinetics of the formation and decomposition of hydroperoxide in the oxidation of 8-pentadecanone

Kinetic parameters for the decomposition of 8-pentadecanone ketohydroperoxides in the oxidized ketone medium and the effect of caprylic acid on the rate and mechanism of hydroperoxide decomposition have been studied. The decomposition of hydroperoxide into molecular products follows mainly the ionic mechanism.

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8- . . , .

     

Infrared study of the interaction of nitric oxide with CuY zeolites

Infrared studies of the interaction of NO with CuY–A zelites have been made over the temperature range from –100°C to 400°C. Several forms of NO adsorption have been found, in particular, a stable cis-dimer at low temperatures.

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- (–100+400°C) NO CuY–A . NO, ë - .

     

Energetic state of hydrogen on Os-black

Hydrogen adsorption on Os-black has been studied by the TPD method in the range from –85 to 450°C. Energetic inhomogeneity of hydrogen chemisorbed at adsorption temperatures of 150 to 450°C has been elucidated.

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OS (–85)–450°C. , 150 450°C.

     

CNDO study of the properties of the OH group

Using the CNDO method, a number of hydroxy-containing systems were calculated. The results are compared with IR spectroscopic data on the frequencies and acidity of surface OH groups and their dependence on the electronegativity of the atom to which the OH group is bonded.

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. - OH- , .

     

Etude de la transition de phase du compose Sb.405Te.595 entre 630 K et 665 K

The present study was performed in an attempt to confirm the existence of the Sb_.405Te_.595 phase transition by employing drop calorimetric method and high temperature X-ray diffractometry. Heat capacity of Sb_.405Te_.595, in the solid state is deduced. Low and high temperature X-ray powder data are given.

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Zusammenfassung Diese Arbeit beschäftigt sich mit dem Nachweis der Existenz der Sb_.405Te_.595 Phasenumwandlung mittels Dropkalorimetertechnik und Hochtemperaturröntgendiffraktometrie. Es wird die Wärmekapazität von Sb_.405Te_.595 im festen Zustand abgeleitet sowie Daten von Nieder- und Hochtemperaturröntgenpulveraufnahmen gegeben.

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Sb_0,405Te_0,595. . - .

     

Thermoanalytical and thermogastitrimetric investigation of oil-shales

From thermoanalytical curves (DTG, TG) recorded in an oxygen atmosphere, the moisture and carbonate contents of oil-shales were determined with acceptable accuracy. The nature of the carbonates was predicted from the shape of the DTG curves above 550°C Dolomite (ankeritc) as found in Gérce oil-shale, and calcite in Pula-9 oil-shale. The clay content was determined from the signal of a water-detector recorded in a nitrogen atmosphere. The peaks at 80°C and 150°C for Gérce oil-shale were attributed to montmorillonite, and the sharp peak at 525°C for Pula-9 oil-shale to kaolinite.The volatile and fixed carbon contents of the oil-shales were calculated from the thermogastitrimetric curves.

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Zusammenfassung Feuchtigkeits- und Carbonatgehalt von Ölschiefern werden aus in Sauerstoffatmosphäre aufgenommenen thermoanalytischen Kurven (DTG, TG) mit annehmbarer Genauigkeit bestimmt. Die Natur der Carbonate wurde aus dem Verlauf der DTG-Kurve oberhalb 550 °C vorausgesagt. Dolomit (Ankerit) wurde im Gérce-Ölschiefer, Calcit im Pula-9-Ölschiefer gefunden. Der Gehalt an Tonen wurde aus dem in Stickstoffatmosphäre erhaltenen Signal eines Wasserdetektors bestimmt. Die Peaks bei 80 und 150 °C in der DTG-Kurve des Gérce-Ölschiefers werden Montmorillonit, der scharfe Peak bei 525 °C im Falle von Pula-9-ölschiefer Kaolinit zugeschrieben. Die Gehalte der Ölschiefer an flüchtigem und fixiertem Kohlenstoff werden aus gastitrimetrischen Kurven berechnet.

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(, ) , , . 550°. (), -9-. . , 80 150° , 525° -9 — . , .

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The authors are indebted to J. Kristóf (Dept. of Anal. Chem., Univ. of Veszprém) for carrying out the continuous water measurements; to K. Labdy (Central Laboratory, Univ. of Veszprém) for the elemental analysis results; to I. Vassányi (Dept. of Mineralogy, Univ. of Veszprém) for the diffractometric results; and to I. Koncz (Hydrocarbon Research and Development Institute, Nagykanizsa) for donating the oil-shale samples.     

Valence states and solubility limits in ternary iron-tin-antimony mixed oxide catalysts

The electrical conductivity study of a series of ternary Fe–Sn–Sb mixed oxides with 5 at. % Fe has shown that iron dissolves in the structure of SnO₂ as ferric ions and, consequently creates acceptor centers which compensate the doping effect of Sb⁵⁺ ions simultaneously dissolved, thus increasing the maximum dissolution of pentavalent antimony and shifting thereby the apparition limit of Sb³⁺ ions towards higher Sb contents.

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Fe–Sn–Sb c 5 . %- Fe , SnO₂ , , Sb⁵⁺, . , Sb³⁺ Sb.

     

Peculiarities of formation of ZnO and CuO-based solid solutions

Low-temperature (623 K) treatment of hydroxocarbonate compounds of copper-zinc and copper-zinc-aluminium leads to the formation of phases with CuO and ZnO structures, which are solid solutions of the promoter ions. The formation of solid solutions is attributed to structural distortions (uniform or local) in the oxide lattice due to the incomplete removal of OH^– and CO ₃ ^2– groups at low temperatures.

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, (623 ) - -- CuO ZnO, . , ( ) - OH ₃ ^–– - .

     

Catalytic autooxidation of hydroquinone in the presence of chelate complexes of transition metals

Autooxidation of hydroquinone was studied in the presence of Co and Cu complexes with salene, decamethyl-octadehydrocorrine, corrine and o-phenanthroline as ligands in aqueous solution and in protic and aprotic solvents. A possible mechanism of the catalytic action of some active complexes is discussed.

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, Co, Cu , , - . .

     

On the pattern of hydrogenolysis of hexane isomers over four Group VIIIB metals

The hydrogenolysis patterns of five hexane isomers have been compared over Rh, Pd, Ir and Pt. The selectivity of rupture of various C–C bond types is different for various metals. The fingerprint-like patterns are, as a rule, similar to those reported in the literature, their correlation with the position of the metal in the periodic system is pointed out.

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5- Rh, Pd, Ir Pt. C–C , . .

     

Relative rate coefficients of⊙OH-radical interactions in nonaqueous medium

For measuring relative rate coefficients of OH-radical reactions in organic media a competitive method has been used. As reference, 2-propanol was applied. For ethylbenzene and 1-phenylethanol the rate coefficients of H-abstraction relative to that of 2-propanol are 1.4 and 2.9, respectively.

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OH. 2-. H 1-, 2-, 1,4 2,9, .

     

Reconstruction of thermokinetics from calorimetric data by means of numerical inverse filters

A simple method for removing the distortion due to thermal lags from calorimetric curves is described and tested. The method is based upon the use of numerical inverse filters. Its results are equivalent to those of the more sophisticated deconvolution methods, using Fourier transform analysis or state function theory. The new method is easily adapted to the on-line reconstruction of calorimetric data by means of a microprocessor.

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Zusammenfassung Eine einfache Methode zur Beseitigung der infolge thermischer Hysterese-Effekte entstandenen Verzerrungen kalorimetrischer Kurven wurde beschrieben und geprüft. Die Methode beruht auf der Anwendung numerischer Inversfilter. Die Ergebnisse sind den durch verfeinertere Dekonvolutionsmethoden unter Einsatz der Analyse durch Fouriertransformation oder durch die Zustandsfunktionstheorie erhaltenen gleichwertig. Die neue Methode läßt sich der on-line Erfassung kalorimetrischer Daten durch einen Mikroprocessor leicht anpassen.

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Résumé Une méthode simple pour la correction de la distorsion des courbes calorimétriques, amenée par l'inertie thermique, est décrite et éprouvée. La méthode est basée sur l'emploi de filtres numériques inverses. Les résultats obtenus sont équivalents à ceux fournis par des méthodes plus complexes de déconvolution, utilisant l'analyse harmonique ou la théorie des variables d'état. La nouvelle méthode peut être facilement adaptée à la correction simultanée des courbes calorimétriques au moyen d'un microprocesseur.

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, . . , - . .

     

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.

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

     

Thermodesorption of mixtures. Hydrocarbon, hydrogen sulfide and oxygen from the surface of molybdenum sulfide

The presence of hydrogen sulfide and oxygen in mixtures increases the number of sites for dissociative desorption on the surface of MoS₂ as compared with the adsorption of individual hydrocarbons. This phenomenon can be explained by a change in the coordination state of the active sites (molybdenum ions) upon the adsorption of the gases mentioned.

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, MoS₂ . .

     

State of components in supported catalysts prepared via interaction of platinum-tin complexes with Al2O3 surface

The interaction of platinum-tin complexes with the OH groups of Al₂O₃ is shown to lead to the formation of surface complexes in which tin ions bonded to the support are not reduced to metal and inhibit platinum agglomeration.

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OH- Al₂O₃ , .

     

Kinetics of thermal decomposition of diacyl peroxides in the presence of aerosil

In the presence of aerosil the thermal decomposition of the polymeric peroxide of sebacic acid is enhanced proportionally to the filler weight fraction in the reaction system. This is attributed to the interaction of peroxide groups with acidic groups on the aerosil surface and their decomposition according to a nonradical mechanism unlike the homolytic radical decomposition in solution.

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, , . .

     

Influence of functional rubbers on the curing process of unsaturated polyester resins

The influence of an elastomeric second-phase on the kinetics of the curing reaction and the gel-time of a standard unsaturated polyester resin, by using the isothermal and dynamic techniques of differential scanning calorimetry (DSC) and a thermocouple was investigated. In particular we examined two different rubbers (polybutadiene hydroxyl-terminated and polybutadiene isocyanate-terminated), that, in the presence of polyester resins, affect the overall curing reaction kinetics in two ways: the former reduces the rate of reaction whilst the latter increases it.

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Zusammenfassung Der Einfluß einer elastomeren Zweitphase auf die Kinetik der Aushärtung und der Gelierungszeit eines als Standard dienenden ungesättigten Polyesterharzes wurden mittels isothermer und dynamischer DSC untersucht. Insbesondere wurden zwei unterschiedliche Gummis (hydroxylendständiges und isocyanatendständiges Polybutadien) untersucht, die die Kinetik der Aushärtung des Polyasterharzes in unterschiedlicher Weise beeinflussen: hydroxylendständiges Polybutadien verringert, isocyanatendständiges dagegen erhöht die Reaktionsgeschwindigkeit.

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, , . ( ) : , — .

     

Decomposition of ammonia on rhenium II. Nitrogen adsorption on rhenium

Field emission microscopy and thermal desorption studies of nitrogen adsorption on a monocrystal tip and a polycrystalline rhenium wire indicate the formation of molecular () and dissociative () forms of adsorption. Adsorption-desorption characteristics have been measured.

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. - - , - .