Collisional energy transfer in the decomposition of 2-methyloxetane and 3-methyloxetane, II. Gas/wall collisions

The variable encounter method has been applied for the study of gas/wall vibrational energy transfer in the thermal decomposition of 2-methyloxetane and 3-methyloxetane. The average probability of reaction per collision was deduced from the data and was compared with stochastic calculations based on gaussian and exponential energy transfer probability models. The gaussian model fits the experimental data best. Using this model, the average down step energies were 2600 and 2690 cm^–1 for 2-methyloxetane and 3-methyloxetane, respectively, at 750 K, and they decreased with increasing temperature.

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/ 2- 3-. , . . , 2600 2690 ^–1 750 K 2- 3-, . .

     

Reactions of butane and isobutane to CO and CO2 catalyzed by iron oxide treated with sulfate ion

Catalysts which were obtained by exposing Fe(OH)₃ and Fe₂O₃ prior to the crystallization to 0.5 N H₂SO₄ and then calcining in air at 500 °C were highly active for oxidations of butane and isobutane to CO and CO₂ below 300 °C, while iron oxides prepared without the sulfate treatment were completely inactive.

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, Fe(OH)₃ Fe₂O₃ 0,5 H₂SO₄ 500 °C CO CO₂, 300 °C, , , .

     

Influence of the nonmetallic component in binary chromium compounds on their catalytic activity in carbon monoxide oxidation

Oxidation kinetics of carbon monoxide on chromium carbide, nitride and boride has been studied. The activity of chromium compounds was compared with the electronic state of the chromium atom according to XPS data. A reaction mechanism is proposed and an assumption is made on the predominant effect of the nonmetallic component on the character of change in the catalytic activity of chromium compounds.

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A study of thermal preparation OF c-Mn2P4O12

With the application of thermogravimetry under quasi-isothermal-isobaric conditions, the reaction course of the calcination of Mn(H₂PO₄ · H₂O to give dimanganese cyclotetraphosphate has been studied. Isothermal calcination was also carried out in an electric furnace at various temperatures (200 min). The reaction products were analyzed by chromatography, IR and NMR spectrocopy, and X-ray diffraction analysis. The compositions of the calcinates were determined through extraction with various inorganic and organic solvents.

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Zusammenfassung Der Verlauf der Dimangan-cyclotetraphosphat ergebenden Kalzinierung von Mn(H₂PO₄)₂ · H₂O wurde thermogravimetrisch unter quasi-isothermen-isobaren Bedingungen untersucht. Isotherme Kalzinierung wurde auch im elektrischen Ofen (200 min) bei verschiedenen Temperaturen ausgeführt. Die Reaktionsprodukte wurden chromatographisch, IR- und NMR-spektroskopisch sowie röntgendiffraktometrisch analysiert. Die Zusammensetzung der kalzinierten Produkte wurde via Extraktion mit verschiedenen anorganischen und organischen Lösungsmitteln bestimmt.

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Mn(H₂PO₄ · H₂O. . . - , - - . .

     

The structures and thermal decomposition of cupric mono,di and trichloracetates

Magnetic moment measurements and ultra-violet diffuse reflectance spectroscopy have been used to investigate the structure of the chloroacetates of copper(II). These studies indicate that cupric monochloroacetate dihydrate is dimeric and cupric trichloracetate tetrahydrate is monomeric. Cupric dichloracetate tetrahydrate forms an intermediate case. The thermal decomposition of these compounds under nitrogen has been studied using thermogravimetry and differential thermal analysis, together with analysis of the products of the decomposition. The major organic product formed in the thermal decomposition of the mono- and dichloracetates is the corresponding chlorinated acetic acid; the solid inorganic product is cuprous chloride. Thermal decomposition of the trichloracetate yields cupric chloride and a mixture of trichloracetic acid and trichloracetyl chloride.

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Zusammenfassung Messungen des magnetischen Momentes sowie diffuse UV-Remissionspektroskopie wurden zur Untersuchung der Struktur der Kupfer(II)-chloracetate eingesetzt. Die Ergebnisse deuten darauf hin, daß Kupfermonochloracetat-Dihydrat dimer und Kupfertrichloracetat-Tetrahydrat monomer ist. Das Kupferdichloracetat-Tetrahydrat bildet hierbei eine Zwischenstufe. Die thermische Zersetzung dieser Verbindungen wurde in Stickstoffatmosphäre unter Anwendung der Thermogravimetrie und Differentialthermoanalyse untersucht, bei gleichzeitiger Analyse der Zersetzungsprodukte. Das bei der thermischen Zersetzung des Mono- und Dichloracetats gebildete organische Hauptprodukt ist die entsprechende chlorierte Essigsäure; der feste anorganische Rückstands das Kupfer(I)-chlorid. Die thermische Zersetzung des Trichloracetats ergibt Kupfer(II)-chlorid sowie eine Mischung von Trichloressigsäure und Trichloracetylchlorid.

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Résumé La mesure du moment magnétique et la spectroscopie de réflexion diffuse dans l'U. V. sont utilisées pour étudier la structure des chloroacétates de cuivre (II). Les résultats indiquent que le monochloroacétate de cuivre (II) dihydraté est dimère et que le trichloroacétate de cuivre (II) tétrahydraté est monomère. Le dichloroacétate de cuivre (II) tétrahydraté représente un cas intermédiaire. La décomposition de ces composés dans l'azote a été suivie par thermogravimétrie et analyse thermique différentielle, en analysant simultanément les produits de décomposition. Le principal produit organique formé lors de la décomposition thermique des mono et dichloroacétates est l'acide chloroacétique correspondant; le produit solide inorganique est le chlorure de cuivre (I). La décomposition thermique du trichloroacétate fournit le chlorure de cuivre (II) et un mélange d'acide trichloracétique et de chlorure trichloroacétylique.

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(II). , (II) , (II) - . (II) . , , . , - , , (I). (II) (II) .

     

Preparation of catalysts by spray decomposition

Spray decomposition of solutions is an uncommon but very promising technique for the preparation of multicomponent solid systems with welldefined structure. The experimental arrangement is described and a summary of the systems prepared until now is given. These are MgO–ZnO, CaO, CdO, Al₂O₃. Fe₂O₃ solid solutions and CdO. CdSO₄ and Al₂O₃. Al₂(SO₄)₃ systems.

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, , . : MgO·ZnO, CaO·CdO,. Al₂O₃·Fe₂O₃ CdO·CdSO₄ Al₂O₃·Al₂ (SO₄)₃.

     

Discrimination of active sites for ethylene homologation and ethylene metathesis on molybdena silica catalyst

Active sites for ethylene homologation (3C₂H₄2C₃H₆) and ethylene metathesis (C₂H₄–¹²C₂+C₂H₄–¹³C₂2C₂H₄–¹³C₁) were discriminated by adding platinum to a reduced molybdena silica catalyst, and the former was presumed to be composed of several molybdenum species, while the latter was presumed to be composed of one molybdenum species.

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(3C₂H₄2C₃H₆) (C₂H₄–¹²C₂+C₂H₄–¹³C₂2C₂H₄–¹³C₁) . , , .

     

Sintering of supported palladium

Sintering results of Pd supported on carbon black at 723–973 K, in water vapor, in H₂ and under high vacuum are reported. They are compared with sintering data of Pd on other supports. The observed sequences are: SiO₂C>sepioliteAl₂O₃>AlPO₄ and H₂O>high vacuum>H₂.

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Pd 723–973 , , H₂ . Pd . : SiO₂Al₂O₃>AlPO₄ H₂O> >H₂.