Regioselective Synthesis of Substituted Triazolium Salts via 1,3-Dipolar Cycloaddition Reactions

The regioselectivity of 1,3-dipolar cycloaddition reactions of 1-aza-2-azoniaallene salts with ,-unsaturated nitriles such as acrylonitrile or cyclohexylidene acetonitrile afforded only 1,2,4-triazolium salts via addition to the nitrile group, while the other expected pyrazolium salts were not observed. Moreover, 1-aza-2-azonia-allene salts reacted with other competitive systems such as -iminonitrile derivatives yielding only triazolium salts via addition to the nitrile and not to the imino group. Treatment of cumulene with 3-pyridylnitrile afforded the pyridinium salt. However, 2,3-dimethyl-5-(2,6-dimethoxyphenyl)-[1,2,4]triazole could be prepared from cumulene and 2,6-dimethoxybenzonitrile. Some reactions of nitriles with 1-aza-2-azonia-allene salts prepared from 1,2,3-indantrione and 9-acetylphenanthrene are discussed.     

Catalytic activity of palladium-containing zeolites in the complete oxidation of benzene

The dependence of palladium distribution in zeolites on the temperature of thermal treatment has been established from the data on oxygen chemisorption and the statistical processing of electron micrographs. The influence of palladium distribution in zeolites on their catalytic activity towards the complete oxidation of benzene has been shown.

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Reaction of the nitrile of 3,3-diphenyl-2-propenic acid with the carbanions of some α-branched nitriles Short communication

Reaction of the nitrile of 3,3-diphenyl-2-propenic acid with -branched nitriles in the presence of lithium amide in liquid ammonia does not give the correspondingMichael adducts but the ,-unsaturated nitriles6. Conc. sulfuric acid transforms these nitriles into the -lactones7.

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Reaktion von 3,3-Diphenyl-2-propensäurenitril mit den Carbanionen einiger -verzweigter Nitrile (Kurze Mitteilung)

Zusammenfassung Die Reaktion von 3,3-Diphenyl-2-propensäurenitril mit -verzweigten Nitrilen in Gegenwart von Lithiumamid in flüssigem Ammoniak führt nicht zu den entsprechendenMichael-Addukten, sondern zu den ,-ungesättigten Nitrilen6. Durch Einwirkung von konz. Schwefelsäure entstehen aus diesen Nitrilen die -Lactone7.

     

Multivariate Statistical Assessment of Air Quality: A Case Study

The present paper deals with the application of several chemometrical methods (cluster and principal components analysis, source apportioning on absolute principal components scores) to an aerosol data collection from Unterloibach, Austria. It is shown that seven latent factors explaining almost 80% of the total variance are responsible for the data structure and are conditionally identified as secondary aerosol, mineral dust, oil burning, lead smelter, coal burning, salt and fertilizer emission sources. Furthermore, the contribution of each identified source to the formation of the particle total mass and chemical compounds total concentration is calculated. Thus, a reliable assessment of the air quality in the region is performed. The requirements of the sustainability concept for ecological indicators in this case is easily transformed into a multivariate statistical problem taking into account not separate indicators but the specific multivariate nature of aerosol pollution.     

1,3-diphenyl-2-azaanthracene and 8-aza-7-phenylbenzo[a]fluoranthene in the diene synthesis

The diene condensation of 1,3-diphenyl-2-azaanthracene with maleic anhydride proceeds under more severe conditions than the analogous condensation with anthracene. On the basis of an analysis of the PMR data for the adduct obtained it was assumed that isomers of ,-[9,10-dihydro-2-aza-1,3-diphenylanthrylene(9,10)]succinic anhydride with respect to the position of the anhydride bridge relative to the pyridine ring are formed in this condensation. 9,10-Dihydro-2-aza-1,3-diphenyl-9, 10-(1-cyanoethylene)anthracene was obtained in the condensation of the same azaanthracene with acrylonitrile. ,-[5H-8-Aza-7-phenylbenzo[a]fluoranthrylene (5,12b) ]succinic anhydride is formed as a result of the similar condensation of 8-aza-7-phenylbenzo[a]fluoranthene with maleic anhydride, while isomeric (with respect to the position of the nitrile group in the ethylene bridge) 5H-8-aza-7-phenyl-5,12b-(cyanoethylene)benzo[a]fluoranthenes were isolated in its condensation with the acrylonitrile. Data from the PMR and IR spectra were used to prove the structures of the adducts of the diene synthesis obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1645–1647, December, 1980.     

Preparation and thermal decomposition of halogenometallates

Five new derivatives of general formula [Ru(dipy)₃]MCl₄, whereM=Cu(II), Zn(II), Mn(II), Fe(II) and Co(II), and [Ru(dipy)₃][FeCl₄]₂ were synthesized, and their compositions and structures were confirmed by chemical analysis and electron absorptionüspectroscopy. The thermal decompositions of the compounds were studied by thermoanalytical methods. All these complexes decompose upon heating up to 1300 K, with simultaneous loss of organic fragments and structures were confirmed by chemical analysis and electron absorption spectroscopy.The exothermic effects. The residues after heating correspond to RuO₂ and the appropriate M oxides, contaminated in some cases by pure metal.

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Zusammenfassung Fünf neue Komplexverbindungen des Typs [Ru(dipy)₃](MCl₄] (dipy=2,2-Dipyridyl;M=Cu, Zn, Mn, Fe, Co) sowie [Ru(dipy₃](FeCl₄]₂ wurden dargestellt und ihre Zusammensetzung und Struktur durch chemische Analyse und Elektronenspektroskopie bestätigt. Ihre thermische Zersetzung wurde durch simultane TG-DTA untersucht. Alle Komplexverbindungen zersetzen sich beim Erhitzen bis auf 1300 K unter gleichzeitigem Verlust der organischen Komponente und des Cl an die Gasphase. Der thermische Abbau ist von starken exothermen Effekten begleitet. Die Rückstände nach dem Erhitzen enthalten RuO₂ und das jeweilige Metalloxid, in einigen Fällen durch Metall verunreinigt.

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[Ru(dipy)₃]MCl₄, M = , , , , [Ru(dipy)₃][FeCl₄]₂. , . 1300 . . , .

     

1,2-bis(2',6'-dimethyl-i',3'-dioxa-6'-aza-2'-silacyclooctyl-2')ethane and the corresponding ethylene and acetylene derivatives

Conclusions The reaction of 1,2-bis(methyldimethoxysilyl)ethane and the corresponding ethylene and acetylene derivatives with bis(2-hydroxyethyl)methylamine gives 1,2-bis(2,6-dimethyl-1,3-dioxa-6-aza-2-silacyclooctyl-2)ethane and the corresponding ethylene and acetylene derivatives. Analogously, 1,2-bis(vinyldimethoxysilyl)acetylene gave 1,2-bis(2-vinyl-6-methyl-1,3-dioxa-6-aza-2-silacyclooctyl-2)acetylene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1420–1421, June, 1988.     

Surface properties of Fe?Mo?O catalysts and their activity in methanol oxidation to formaldehyde

The Fe^III–Mo^VI–O catalyst was prepared from iso-ortho-Fe(OH)₃ and -FeOOH. The catalysts differed markedly in their activity in methanol oxidation depending on the biography of their iron(III) oxide. The catalytic properties were found to depend on the pore structure of the catalyst.

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Fe(III)–Mo(VI)–O, --Fe(OH)₃ -FeOOH. , . , .

     

Oxidation of Substituted Benzyl Alcohols by Quinoxalinium Dichromate. A Kinetic Study

Summary. Quinoxalinium dichromate (QxDC) oxidizes benzyl alcohol and substituted benzyl alcohols smoothly in dimethyl sulfoxide (DMSO) and in the presence of acid to the corresponding aldehydes. The reaction has unit dependence on each of the alcohol, QxDC, and acid concentrations. Electron-releasing substituents accelerate the reaction, whereas electron-withdrawing groups retard the reaction, and the rate data obey Hammetts relationship. The reaction constant was –1.09±0.01 at 303K. Oxidation of ,-dideuteriobenzyl alcohol indicated the presence of a substantial primary kinetic isotope effect (k_H/k_D=6.78 at 303K). The reaction failed to induce the polymerization of acrylonitrile. The rates of oxidation were determined at different temperatures and the activation parameters were evaluated. The analysis of the dependence of the kinetic isotope effect on temperature indicated that the reaction involves a symmetrical cyclic transition state. A suitable mechanism is proposed.     

Infrared study of the adsorption and reactions of nitric oxide on CuY zeolites

The adsorption and the reactions of nitric oxide on CuY zeolites with copper ions in various states have been studied by IR-spectroscopy. Forms of NO adsorbed on individual Cu²⁺ ions, on weak and strong magnetic formations, and on Cu⁺ ions have been observed. Processes of oxidation and reduction of NO to NO₂, N₂O and N₂ occurring on CuY zeolites are discussed. Adsorption of nitrogen on coordinatively unsaturated copper ions has been observed.

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- CuY . NO Cu²⁺, Cu¹⁺. --, CuY NO₂, N₂O N₂. .

     

Errors in the determination of activation energies of solid-state reactions by the Piloyan method,as a function of the reaction mechanism

The errors in the activation energies of solid-state reactions determined with the Piloyan method are more larger than those previously assumed in the literature. On the other hand, the errors in the kinetic parameters are strongly dependent on the kinetic law obeyed by the reaction. A theoretical explanation of this behaviour is given.

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Zusammenfassung Die Fehler der nach der Piloyan-Methode bestimmten Aktivierungsenergien von Festkörperreaktionen sind grö\er als bisher in der Literatur angenommen und stark abhÄngig von der Reaktionsordnung. Eine theoretische ErklÄrung dieses Verhaltens wird gegeben.

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, , . , , , . .

     

Hydrogen pressure dependence of the reaction of neopentane with hydrogen over Pd/SiO2 and Pt/SiO2 catalysts

H₂ pressure influences in different ways the reaction rates of neopentane conversion over Pd/SiO₂ and Pt/SiO₂ catalysts. It seems that on Pt/SiO₂ both isomerization and hydrogenolysis involve a common surface intermediate (probably an adalkyl), whereas on Pd/SiO₂ the hydrogenolysis goes via more dehydrogenated species than those involved in isomerization.

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H₂ Pt/SiO₂ Pd/SiO₂. , Pt/SiO₂ (, ), Pd/SiO₂ , .

     

Low-temperature regeneration of activated carbon

Activated granular carbon samples, routinely equilibrated with synthetic aqueous solutions of o-NO₂-phenol, were regenerated by heating up to 500 °C in a dynamic N₂ atmosphere. Kinetic evaluation of five subsequent thermodesorption cycles was accomplished by two different non-isothermal computation methods. Quantitative estimation of adsorbent-adsorbate interactions was carried out by means of the thermal coefficient of the massive adsorbate release.

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Zusammenfassung Routinemäßig mit synthetischen wässrigen Lösungen von o-Nitrophenol äquilibrierte, granulierte Aktivkohle-Proben wurden durch Aufheizen auf 500 °C in einer dynamischen N₂-Atmosphäre regeneriert. Fünf aufeinanderfolgende Thermodesorptionszyklen wurden nach zwei verschiedenen nicht-isothermen Berechnungsmethoden kinetisch ausgewertet. Die quantitative Bestimmung der Adsorbent-Adsorbat-Wechselwirkungen wurde mittels der thermischen Koeffizienten der massiven Adsorbatdesorption ausgeführt.

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, - , 500 ° . . — .

     

Studies of the reaction mechanism between copper(II) sulphate and excess copper(I) sulphide

The reaction process between CuSO₄ and excess Cu₂S in the temperature range 650–750 K was investigated by methods of thermal analysis and by studying the phase contentss of the products as a function of the fractional conversion. The reaction proceeds in three steps, with Cu₂S and a new phase described by the formula Cu₂SO₂ as intermediates. This new phase is liquid under the conditions of the reaction. The final product of the reaction is a defective crystalline Cu₂O.

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Zusammenfassung Der Verlauf der Reaktion zwischen CuSO₄ und überschüssigem Cu₂S im Temperaturbereich von 650–750 K wurde mittels thermoanalytischer Methoden und durch Ermittlung der Phasenzusammensetzung in AbhÄngigkeit von der Konversion untersucht. Die Reaktion verlÄuft in drei Schritten mit Cu₂S und einer neuen Phase der Zusammensetzung Cu₂SO₂ als Zwischenproduke. Die neue Phase ist unter den Reaktionsbedingungen eine Flüssigkeit. Endprodukt der Reaktion ist nicht völlig kristallines Cu₂O.

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CuSO₄ Cu₂S 650–750 K . Cu₂S , Cu₂SO₂ . Cu₂O .

     

Electronic modification effect of rare earth oxide upon Pt in Pt-Dy/γ-Al2O3 catalysts

The surface properties of Pt-Dy/-Al₂O₃ catalysts have been investigated by TPR and HOT techniques. Catalytic properties in the reaction of n-hexane, cyclopentane, and benzene on Pt/-Al₂O₃ and Pt-Dy/-Al₂O₃ catalysts have been studied in a pulsed microcatalytic reactor. The effect of dysprosium in Pt-Dy/-Al₂O₃ catalysts is also discussed.

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Pt-Dy/-Al₂O₃ TPR HOT. Pt/-Al₂O₃ Pt-Dy/-Al₂O₃ -, . Pt-Dy/-Al₂O₃.

     

Acidity dependence of aniline alkylation activity over modified alumina+

-Al₂O₃ is modified by lithium additions and by calcination. Aniline alkylation activity over modified alumina is correlated with the Al–OH group population responsible for the acidity.

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-Al₂O₃ . Al–OH, .

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IICT Communication No.: 2824     

Cyclization of O-benzoyl-β-piperidinopropionamidoximes to form 5-phenyl-3-(β-piperidino)ethyl-1,2,4-oxadiazoles

The reactions of -piperidinopropionamidoxime with substituted benzoyl chlorides afforded O-benzoylation products, which underwent cyclization to form 5-phenyl-3-(-piperidino)ethyl-1,2,4-oxadiazoles upon heating in dimethylformamide in the presence of molecular sieves at 60 °C for 1—2.5 h. Heating of O-benzoyl--piperidinopropionamidoxime in dimethylformamide in the presence of K₂CO₃ at 85 °C for 4 h afforded a mixture of 5-phenyl-3-(-piperidino)ethyl-1,2,4-oxadiazole, benzoic acid, and N-(-piperidino)ethylurea.     

Standardization in thermal analysis

The present state of the certification of the reference materials for thermal analysis is considered. Six sets of reference materials for temperature calibration, resulting from the research work of the ICTA Standardization Committee, are discussed.

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Zusammenfassung Die gegenwÄrtige Lage der Attestierung von Referenzmaterialien für die thermische Analyse wird erörtert. Sechs Sets von Referenzmaterialien, die vom ICTA-Standardisierungskomitee zur Temperaturkalibrierung in Vorschlag gebracht wurden, werden diskutiert.

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. , .

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The author is most grateful to Professor P. D. Garn, Akron University, USA, and to Dr. Robert C. Mackenzie, The Macaulay Institute for Soil Research, Aberdeen, Scotland, for published material and unpublished data concerning the problems of ICTA standards and the nomenclature of thermal analysis.     

Effect of oxygen migration on the oxidation rate of radicals in n-butanol glass at T=90 K

The effect of n-butanol glass annealing on the oxidation kinetics of radicals and phenanthrene phosphorescence quenching by oxygen at T=90 K has been studied. It has been established that the influence of matrix annealing is due to the migration retardation of oxygen molecules.

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- 90 . .

     

Relationship between kinetic and thermodynamic characteristics of alumosilicate catalysts

The kinetics of cumene dealkylation over alumosilicate catalysts of different nature has been investigated and the calculated thermodynamic adsorption heats of cumene and benzene are given. It is shown that the adsorption heats of cumene and benzene do not depend on the temperature or surface coverage in the region under study. A correlation between the activation energies and the adsorption heats of reaction components is observed.

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. , . .