Calculation of adsorption heats of nitric oxide on ruthenium by the bond interaction method

Chemisorption heats of nitric oxide on Ru(0001) and Ru(1010) planes have been calculated by the bond interaction method. It is shown that the calculated values correlate well with TPD data.

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(000I) (I0I0) . , .

     

Synthesis of thiolane from tetrahydrofuran and H2S in the presence of proton-donor catalysts

In the presence of proton-donor catalysts, at 300–400°C tetrahydrofuran interaction with H₂S yields up to 25% thiolane. These catalysts are low-selective and have low stability due to the occurrence of decomposition and polymerization processes.

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300–400°C H₂S 25%. .

     

Hydrocarbon synthesis from methanol on erionite and mordenite catalysts synthesized in the presence of B3+, Ga3+ or Fe3+

Selectivity of erionite and mordenite type aluminosilicates synthesized in the presence of B³⁺, Ga³⁺ or Fe³⁺ has been studied in methanol conversion to hydrocarbons. The olefin to paraffin ratio in the product is proportional to the Al₂O₃ content of the zeolites.

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, B³⁺, Ga³⁺ Fe³⁺. , / Al₂O₃ .

     

Synthesis of methylmercaptane in the presence of base catalysts

Interaction of methanol with H₂S has been studied at 360–500°C in the presence of Al₂O₃ promoted by alkaline metal compounds. As found, catalysts, obtained via promoting Al₂O₃ by carbonate, and potassium or sodium hydroxide, are more basic in relation to tung-state samples. The total catalytic activity increased, while the selectivity toward methylmercaptane decreased with increasing surface basicity.

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360–500°C Al₂O₃, . , , Al₂O₃ , . - .

     

Reaction between the OH group of hydroxyproline and diisocyanate catalyzed by an organotin compound

We have studied the kinetics of the reaction of L-hydroxyproline with OCH(CH₂)₆NCO, catalyzed by organotin, avoiding side reactions by protecting the other active hydrogens of the aminoacid, and comparing it with the MeOH/n-BuNCO system.

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L-- -OCN(CH₂)₆NCO, , . . - .

     

Phase-transfer oxidation of hydrocarbons by molecular oxygen in the absence of metals

Lipophilic quaternary ammonium salts act as phase-transfer agents for Br^– during oxidations of hydrocarbons with molecular oxygen in aqueous-organic systems. The oxidation proceeds also in the absence of transition metal. Bromide anions are precursors to the chain reaction initiator.

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- , . .

     

Transformed steroids. 133. Synthesis of 20-deoxysteroids with a tetrahydropyran ring E

The synthesis of 20-deoxy compounds — the precursors of the steroid pyranols and pyranones synthesized by the authors previously — has been effected from a steroid 20-ketotetrahydropyran by the hydrogenolysis of the corresponding ethylene dithioketal with Raney nickel. The¹H and¹³C NMR spectra have been studied in detail. Transformations of rings A and B via the epoxide or the 3,5-cyclosteroid have led to 3-acetoxy-16,23-epoxy-5H-21,24-dinorchol-5-en-6-one and 3-acetoxy-5-hydroxy-16,23-epoxy-21,24-dinorchol-5-en-6-one.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 732–735, November–December, 1983.     

Synthesis and properties of azoles and their derivatives. 10. Synthesis of 3,5-diaryl-4-nitroisoxazoles

A method was proposed for the synthesis of 3,5-diaryl-4-nitroisoxazoles entailing the brominatian of potassium salts of the corresponding 3,5-diaryl-²-isoxazolinyl-4-nitronic acids. The method may be used for the conversions of both the trans and cis isomers of 3,5-disubstituted 4-nitro-²-isoxazolines.Communication 9, See [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 189–192, February, 1985.     

Synthesis of light alcohols from carbon monoxide and hydrogen over copper-iron catalysts

The activity and selectivity of copper-iron catalysts for the synthesis of light alcohols from carbon monoxide and hydrogen were studied. The suitable ratio of copper to iron and optimal chemical composition of the catalyst were determined.

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- . .

     

ESR study of the interaction of oxygen and propene with solid CoO?MgO solutions under pulse conditions

An ESR study has shown that under the action of oxygen pulses, radical ions O ₂ ^– with g_I=2.0085 and g_II=2.087 are generated at room temperature on the surface of 1% CoO–MgO. Heating of the sample to 150 °C in the spectrometer results in complete disappearance of the O ₂ ^– signal from the ESR spectra. The variation of the O ₂ ^– signal intensity with time due to the interaction between propene and oxygen adsorbed on the sample surface, has been measured.

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, 1% CoO–MgO - O ₂ ^– g_I=2.0085 g_II=2.087. 150 °C - O ₂ ^– . O ₂ ^– .

     

Thermal analysis of mercury(I) sulfate and mercury(II) sulfate

The thermal decomposition of mercury(I) and (II) sulfates has been investigated by thermogravimetry. The solid-state decomposition products have been characterized by infrared and Raman spectroscopy, mass spectrometry and an X-ray diffraction method. It is concluded that mercury(I) sulfate decomposes in two steps, initially forming a mixture of metallic mercury and mercury(II) sulfate — the latter subsequently decomposes without forming a stable intermediate. The stoichiometry of disproportionation of mercury(I) sulfate and the thermal stability range of mercury(I) and mercury(II) sulfates have been established.

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Zusammenfassung Die thermische Zersetzung von Quecksilber(I) und (II)-sulfaten wurde durch Thermogravimetrie untersucht. Die Festphasen-Zersetzungsprodukte wurden durch Infrarot- und Ramanspektroskopie, Massenspektrometrie und Röntgendiffraktion charakterisiert. Es wurde gefolgert, dass Quecksilber(I)sulfat in zwei Stufen zersetzt wird, unter anfänglicher Bildung eines Gemisches von metallischem Quecksilber und Quecksilber(II)-sulfat, welches in der Folge ohne Bildung eines stabilen Zwischenproduktes zersetzt wird. Die Stöchiometrie der Disproportionierung des Quecksilber(I)sulfats und der Bereich der Thermostabilität der Quecksilber(I) und Quecksilber(II)sulfate wurden ermittelt.

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Résumé La décomposition thermique des sulfates de mercure(I) et de mercure(II) a été suivie par TG. On a caractérisé les produits de la décomposition en phase solide par spectroscopies infrarouge et Raman, spectrométrie de masse et diffraction des rayons X. On en a conclu que le sulfate de mercure(I) se décompose en deux étapes, formant initialement un mélange de mercure métallique et de sulfate de mercure(II), ce dernier se décomposant ensuite sans formation d'un intermédiaire stable. Les proportions stoechiométriques de la dismutation du sulfate de mercure(I) et de l'intervalle de stabilité thermique des sulfates de mercure(I) et de mercure(II) ont été établis.

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- . , , . , , (), - . - .

     

Synthesis of Pd(II) nitro and nitrate complexes and studies of their reactivity towards oxidation of olefins in organic solvents

Complexes of the composition Pd(NO_n)_2–mCl_mL₂ (n=2, 3; m=0, 1, 2; L=CH₃CN) have been synthesized and their reactivity in ethylene and propylene oxidation has been examined. Data on the influence of the ligands, solvents and olefins on the composition of reaction products are reported.

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Pd(NO_n)_2–mCl_mL₂ (n=2, 3; m=0, 1, 2; L=CH₃CN) . , .

     

Sulfurization of Pt/Al2O3?Cl catalysts. IV. Adsorption sites of H2S on Al2O3, Al2O3?Cl and Pt/Al2O3?Cl

Chemisorption of H₂S on Al₂O₃, Al₂O₃–Cl and Pt/Al₂O₃–Cl has been studied by gravimetry and IR spectroscopy. The influence of the amount of Cl on the H₂S adsorption equilibrium value and the nature of the adsorption sites at low and high coverages are discussed.

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H₂S Al₂O₃, Al₂O₃–Cl Pt/Al₂O₃–Cl . Cl H₂S, .

     

Halogen-containing Pyridines. 8. Synthesis of 3,5-Dichloropyridines Containing Pyrazole and Pyrazoline Residues in Position 2

The interaction of 3,5-dichloro-2-pyridylhydrazine with ,-unsaturated carbonyl compounds leads to 1-(3,5-dichloro-2-pyridyl)-3,5-disubstituted ²-pyrazolines. It was shown that N-(3,5-dichloro-2-pyridyl)hydrazones of the corresponding aldehydes and ketones are formed as intermediates. Condensation of the hydrazine mentioned above with ,-diketones gives 1,3,5-trisubstituted pyrazoles, but with acetoacetic ester a 1,3-disubstituted pyrazol-5-one containing a 3,5-dichloropyridyl residue is obtained.     

Thermal and structural properties of rare earth exchanged zeolites

A series of rare earth zeolites of types X and Y were prepared by cation exchange. Thermal analysis curves (TG/DTA) were employed to estimate the structural changes in the zeolite framework. Analogous investigations were carried out by independent methods such as XRD and IR spectroscopy. The results indicate increased thermal stability on the replacement of sodium by rare earth. Partial replacement of rare earth by ammonium/hydrogen enhances the thermal stability. The type Y zeolites are more stable than those of X type.

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Zusammenfassung Eine Reihe von Ionen der Seltenen Erdmetalle enthaltenden Zeolithen des Typs X und Y wurden durch Ionenaustausch hergestellt. Thermoanalytische Kurven (TG/DTA) wurden zur Beurteilung der strukturellen Veränderungen des Zeolithgitters herangezogen. Analoge Untersuchungen wurden mit unabhängigen Methoden (XRD und IR-Spektroskopie) ausgeführt. Es wurde festgestellt, daß ein Ersatz der Natriumionen durch Ionen der Seltenen Erdmetalle zu einer Erhöhung der thermischen Stabilität führt. Ein teilweiser Ersatz der Seltenen Erdmetallionen durch Ammonium-/Wasserstoffionen erhöht die thermische Stabilität. Zeolithe des Typs Y sind stabiler als die des X-Typs.

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X . (/) . - . . . X .

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NCL Communication No: 2186     

Synthesis of unsaturated diketones and δ2-pyrazoline derivatives from terephthalaldehyde

,-Unsaturated diketones were obtained by the condensation of terephthalaldehyde with aromatic and heterocyclic methyl ketones. The reaction of the diketones with phenyl-hydrazine gave 1,4-bis(1-phenyl-3-aryl-²-pyrazolin-5-yl)benzenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1094–1096, August, 1971.     

Synthesis of dimethyl sulfide in the presence of zeolites

In the presence of zeolites, dimethyl sulfide is produced either through CH₃OH interaction with H₂S or via CH₃SH decomposition. In accordance with their activities, in both reactions, zeolites arrange in the same sequence: HZSMHNaY>NaXNaY. Realization of the reaction CH₃OH+H₂S is more difficult compared to methanethiol decomposition.

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CH₃OH H₂S CH₃SH. : HZSMHNaY>NaXNaY. CH₃OH+H₂S , .

     

Interdependence between the dispersion of a solid decomposition product and its formation rate

In an analysis of the possible mechanism and kinetics of a thermal decomposition reaction with the formation of a solid product, the following features were considered: the collective rearrangement character of the transformation; the formation of a product with a different non-equilibrium defectiveness and free energy; the free energy relationship in the series of processes leading to products with different dispersions; the formation of intermediate structures; and the spinodal character of their decomposition. Relationships are presented between the rate of solid product formation, the process temperature, and the surface area and size of the particles.

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Zusammenfassung In einer Analyse des möglichen Mechanismus und der Kinetik einer unter Bildung eines festen Produktes verlaufenden thermischen Zersetzungsreaktion werden folgende Besonderheiten erörtert: der kollektive Umordnungscharakter der Umwandlung, die Bildung eines Produktes mit unterschiedlicher Nichtgleichgewichts-Gitterstörung und unterschiedlicher freier Energie, die Beziehung der freien Energie in zu Produkten unterschiedlicher DispersitÄt führenden Prozessen, die Bildung intermediÄrer Strukturen und der spinodalen Charakter ihrer Zersetzung. Beziehungen zwischen der Bildungsgeschwindigkeit des festen Produktes, der Temperatur des Prozesses und der OberflÄchengrö\e und Grö\e der Partikel werden angegeben.

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: ; ; , ; . , , .

     

Effect of ligands on the hydrogenation selectivity in the presence of rhenium catalysts

It has been established that the catalytic activity of rhenium oxohalide complexes with phosphorus- or sulfur-containing ligands in hydroganation of C₆–C₁₀ olefins, nitrobenzene and p-nitrotoluene is primarily determined by the original ligand to rhenium ion bond. Chain length of olefins does not affect their hydrogenation rate.

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- C₆–C₁₀, - - . .