Dimerization of N-methylanabasine in the presence of metallic sodium

In a study of the dimerization of N-methylanabasine in the presence of metallic sodium under conditions for the dimerization of pyridine, it was found that the reaction does not take place at room temperature while at 50–70° C it leads to the formation of,-di(1-methylpiperid-2-yl)-,-bipyridyl. Oxidation of the latter yielded 4,4-bipyridyl-5, 5-dicarboxylic acid, the decarboxylation of which gave,-bipyridyl.     

Synthetic studies in the field of chlorobium chlorophyll

By the condensation of -halogenomethyl derivatives of pyrroles with -unsubstituted pyrroles the synthesis of the following unsymmetrical dipyrrolylmethanes has been effected: 5-benzyloxycarbonyl-5-ethoxycarbonyl-3, 3-di(-methoxycarbonylethyl)-4,4-dimethyl-2,2-dipyrrolylmethane (IIIa), 5-benzyloxycarbonyl-5-ethoxycarbonyl-3-(-methoxycarbonylethyl)-4, 4-diniethyl-3-n-propyl-2,2-dipyrrolylmethane(IIIb), 3-acetyl-5-benzyloxycarbonyl-4-ethyl-5-methoxycarbonyl-3, 4-dimethyl-2,2-dipyrrolylmethane (IIIc), and 3-bromo-5-benzyloxycarbonyl-4-ethyl-5-methoxycarbonyl-3, 4-dimethyl-2,2-dipyrrolylmethane (IIId). Hydrogenation of the unsymmetrical dipyrrolylmethanes IIIa, b, c, and d has given the corresponding monocarboxylic acids IVa, b, c, and d. The formylation of the dipyrrolylmethanemonocarboxylic acid IVa has given 5-ethoxycarbonyl-5-formyl-3,3-di(-methoxycarbonylethyl)-4, 4-dimethyl-2,2-dipyrrolylmethane (V).For communication II, see [1].Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1045–1047, August, 1970.     

New chiral acyclic analogs of 2′-deoxynucleosides

Convenient methods for the synthesis of chiral 2,3-seco-2-deoxynucleosides were developed. An isopropylidene protective group was used to block the 3,5-hydroxy groups in 2,3-seco-uridine. Conversion of the hydroxymethyl group to a methyl group was accomplished by chlorination with a mixture of CCl₄ and Ph₃P with subsequent reduction with n-Bu₃SnH. 2,3-seco-2-Deoxyuridine was obtained after deacetonation. The (S) enantiomer was similarly synthesized starting from 1-(-D-arabinofuranosyl)uracil. 3-O-tert-Butyldimethylsilyl-5-O-(p-monomethoxytrityl)-2,3-seco-2-deoxyuridine, which has optically active centers at C₍₁₎ and C₍₄₎, was also synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 822–826, June, 1988.The authors thank Professor M. Ya. Karpeiskii for his constant interest in this research.     

Hydrogenation of theΒ and γ isomers of 1,4-bis(4′-hydroxy-1′,2′, 5′-trimethyl-4′-piperidyl)-1,3-butadiyne

The kinetics of the hydrogenation of the and isomers of 1,4-bis(4-hydroxy-1, 2, 5-trimethyl-4-piperidyl)-1, 3-butadiyne in methanol and ethanol on the catalysts Raney nickel, platinized carbon, and palladium on supports has been studied. It has been shown that the rates of hydrogenation of the and isomers differ on all the catalysts. In the presence of platinum and nickel, hydrogenation takes place as far as the saturated compound, and in the presence of palladium to the diene.     

Podand-porphyrins with peripheral chelates

Alkylation of 5-(3-nitro-4-hydroxyphenyl)-10,15,20-triphenylporphyrin with chloropyridines[2,6-dichloromethyl-and 2-chloromethyl-6-(2-nitrophenoxymethylpyridine)] as well as condensation by a mixed-aldehyde method starting with formylpyridines [2-(2-nitro-4-formylphenoxymethyl)-6-(2-nitrophenoxy-methyl-) or 2,6-di(2-nitro-4-formylphenoxymethyl)pyridine], benzaldehyde, and pyrrole are used to synthesize previously unknown podand-porphyrins containing from one to four peripheral chelates.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 475–481, April, 1991.     

Performance of a cobalt oxide catalyst in the oxidation of NH3 to NO

The cause for a fall in the conversion of NH₃ to NO within 73 hours from 97% to 78% with a cobalt oxide catalyst was investigated. Results show that sintering, change in valence and cation distribution in Co₃O₄ contribute to the decrease in activity. Incorporation of ThO₂ and K₂O improves the performance of the catalyst.

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NH₃ NO 73 97% 78%. , , Co₃O₄. ThO₂ K₂O NH₃ NO.

     

Investigation of the chemisorption of propylene on zinc oxide by temperature-programmed desorption

The interactions of propylene with zinc oxide have been studied by temperature-programmed desorption (TPD) under experimental conditions free of inter- or intraparticle limitations or readsorption phenomena.The results indicate that propylene is adsorbed on two types of active sites, and the Arrhenius parameters for the corresponding desorption processes have been calculated; moreover, on the basis of these results, important hypotheses can be made regarding the reaction mechanisms of the total oxidation and the dehydroaromatization of propylene on zinc oxide.The experiments confirm that thermal methods can be successfully used in the interesting and important field of heterogeneous catalysis.

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Zusammenfassung Die Wechselwirkungen von Propylen mit Zinkoxid wurden durch temperaturprogrammierte Desorption (TPD) unter Versuchsbedingungen frei von inter- oder intrapartikulären Begrenzungen oder Readsorptionserscheinungen untersucht.Die Ergebnisse zeigen, daß Propylen an zwei Typen von aktiven Stellen adsorbiert wird. Die Arrhenius-Parameter für die entsprechenden Desorptionsprozesse wurden berechnet. Aufgrund dieser Ergebnisse können wichtige Hypothesen bezüglich des Reaktionsmechanismus der totalen Oxidation und der Dehydroaromatisierung von Propylen an Zinkoxid aufgestellt werden.Die Versuche bestätigen, daß thermische Methoden auf dem interessanten und wichtigen Gebiet der heterogenen Katalyse mit Erfolg eingesetzt werden können.

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- , . , . . , . , .

     

Reactivity of polychloroalkyl radicals in the cotelomerization of ethylene and 1-hexene with carbon tetrachloride

The kinetics of cotelomerization of ethylene and 1-hexene with carbon tetrachloride has been studied. Chain transfer and cotelomerization constants have been calculated for several polychloroalkyl radicals.

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I- 303–398 . .

     

Solid-gas reactions: Study of sulphation of limestone using thermogravimetry

Comparative data are presented on the absorption rate and capacity for SO₂ capture by a natural Polish limestone with and without sodium chloride additive. Two sets of experiments were carried out, under dry and wet conditions during limestone calcination and sulphation.The presence of water vapour brought about a higher reactivity of the sorbent, probably as a result of an effect on the sintering of lime and through the influence of the CaSO₄ layer. Further morphological investigations could provide confirmation of the present hypothesis.

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Zusammenfassung Absorptionsgeschwindigkeit und -kapazität für SO₂ an einem polnischen Kalkstein mit oder ohne NaCl-Zusatz werden verglichen. Zwei Reihen von Experimenten wurden in trockener bzw. wasserdampfhaltiger Atmosphäre bei der Calcination und Sulfatbildung durchgeführt. In Gegenwart von Wasserdampf wird die Reaktivität des Absorbens infolge Sinterung des Kalks und trotz des Einflusses der CaSO₄-Schicht erhöht. Künftige morphologische Untersuchungen sollen diese Hypothese eventuel bestätigen.

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. . , , . .

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The author would like to thank Prof. E. M. Bulewicz of this Institute for valuable discussions, and Mr. W. Balcerowiak for making available the facilities of the Laboratory of the Institute of Heavy Organic Synthesis in Kdzierzyn-Kole.     

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 , .

     

Kinetics of the thermal dehydration of variscite and specific surface area of the solid decomposition products

The surface properties of active solids resulting from decomposition of AlPO₄ · 2 H₂O by thermal treatment in vacuum and in air are studied in connection with the parameter governing the kinetics of the dehydration process. The values obtained for the activation energies of decomposition under isothermal conditions agree acceptably well with those computed from TG curves by the Freeman and Carroll method. Kinetic results, which are analysed in terms of the Mampel theory, strongly suggest that the activation energy of the nucleation process determines the rate of surface formation, and justify the observed fact that the specific surface areas of samples treated in vacuum are higher than those of samples treated in air.

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Zusammenfassung Die Oberflächenbeschaffenheiten der aktiven Festkörper, welche bei der thermischen Behandlung im Vakuum oder in Luft als Zersetzungsprodukte von AlPO₄ · 2 H₂O entstehen, werden im Zusammenhang mit dem die Kinetik des Dehydratisierungsvorganges steuernden Parameter studiert. Die bei isothermen Bedingungen für die Aktivierungsenergien der Zersetzung erhaltenen Werte sind in befriedigender übereinstimmung mit denjenigen, welche mittels der Methode von Freeman und Carroll aus den TG-Kurven errechnet wurden. Die gemäß der Mampel-Theorie analysierten kinetischen Ergebnisse lassen darauf schließen, daß die Aktivierungsenergie der Nukleationsvorgänge die Geschwindigkeit der Oberflächen-Entstehung bedingt und rechtfertigen die Beobachtung, nach welcher die spezifische Oberfläche vakuumbehandelter Proben größer ist als die der luftbehandelten.

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Résumé On étudie les propriétés de surface des solides actifs provenant de la décomposition de AlPO₄ · 2 H₂O par traitement sous vide et dans l'air et on les rapporte aux paramètres gouvernant la cinétique du processus de déshydratation. Les valeurs obtenues en conditions isothermes pour les énergies d'activation de la décomposition sont en accord acceptable avec celles calculées à partir des courbes TG par la méthode de Freeman et Carroll. Les résultats cinétiques qui sont analysés dans le sens de la théorie de Mampel font conclure que c'est l'énergie d'activation du processus de nucléation qui détermine la vitesse de la formation de la surface; ils justifient le fait observé que la surface spécifique des échantillons traités sous vide est plus grande que celle des échantillons traités dans l'air.

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, Al ₄ · 2₂ , , . , , , . , , , , , , , , .

     

Comparison of the sulfurization of CoMoK/Al2O3 catalyst with H2S and CS2

Only H₂S consumption and H₂O formation was found in the sulfurization of CoMoK/Al₂O₃ water gas shift catalyst with H₂S/H₂, but CO₂ was formed first, then CH₄, H₂O and H₂S appeared in the later part of TPS with CS₂/H₂. Carbon deposition on the catalyst during the sulfurization with CS₂/H₂ caused a lower activity than the catalyst sulfurized with H₂S but could be removed in the run of WGS reaction.

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, CoMoK/Al₂O₃, H₂S/H₂ H₂S H₂O, CS₂/H₂ CO₂ CH₄, H₂O H₂S. CS₂/H₂ H₂S, , .

     

Effect of reduction temperature on the dehydrocyclizing activity of pure chromia and chromia containing K2O and CaO

The dehydrocyclization of n-heptane at 520–550°C over pure chromia and chromia with added CaO and K₂O (5 wt.% each) has been investigated. Introduction of an alkaline additive into Cr₂O₃ decreases markedly the yield of toluene. Raising of the reduction temperature of alkali-containing samples from 550 to 700°C results, in contrast to pure Cr₂O₃ and chromia-alumina systems, not in diminished, but in increased yields of toluene, the activity enhancement being particularly pronounced for the CaO-containing catalyst. These increased activities cannot be correlated either with variations in specific surface area or changes in the content of Cr⁶⁺ during subsequent oxidation, and presumably should be ascribed to more extensive catalyst reduction at higher temperatures.

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- 520–550° CaO K₂O ( 5% .). Cr₂O₃ . 550° 700° , Cr₂O₃ , , , CaO. , , .

     

Activation energies of the thermal decompositions of C3AH6 AND C3AD6 by the isothermal TG method

Dehydroxylation of C₃AH₆ and C₃AD₆ minerals was studied by means of the isothermal TG method in ambient air and in a constant stream of nitrogen. It was found that the mechanism of dehydroxylation changed during the reaction in ambient air. In a dynamic inert atmosphere the experimental data conform very closely to a first order kinetics model. The activation energy values 85.4 kJ · mole^–1 and 103.4 kJ · · mole^–1 were obtained for C₃AH₆ and for C₃AD₆ samples, respectively.

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Zusammenfassung Die Dehydroxylierung der Mineralien C₃AH₆ und C₃AD₆ wurde mittels isothermer TG-Methode in Luft und in einem konstanten Stickstoffstrom untersucht. Hierbei zeigte sich, daß sich der Mechanismus der Dehydroxylierung während der Reaktion in Luft ändert. Wenn in einer dynamischen inerten Atmosphäre gearbeitet wird, sind die Daten in guter Übereinstimmung mit einem kinetischen Modell erster Ordnung. Aktivierungsenergien von 85.4 kJ · mol^–1 für C₃AH₆ und 103.4 kJ · mol^–1 für C₃AD₆ wurden erhalten.

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Résumé On a étudié la déshydroxylation des minéraux C₃AH₆ et C₃AD₆ par TG isotherme, dans l'air et dans un courant constant d'azote. Dans l'air ambiant, on trouve que le mécanisme de la déshydroxylation se modifie pendant la réaction. En travaillant dans une atmosphère inerte dynamique, les données d'expérience sont en bon accord avec un modèle cinétique du premier ordre. On a obtenu les énergies d'activation suivantes: 85.4 kJ · mol^–1 pour C₃AH₆ et 103.4 kJ · mol^–1 pour C₃AD₆.

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(III) . ²²⁰Rn ( ) , . , . (III) , —²²⁸Th. , , , .

     

The influence of CSH phase nuclei on Ca3SiO4Cl2 hydration

The influence of CSH phase nuclei on calcium chlorosilicate hydration has been studied by means of calorimetry, QXRD, DTA and TG methods.

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Zusammenfassung Mittels kalorimetrischen, QXRD-, DTA- und TG-Verfahren wurde der Einfluß von CSH Phasenkörpern auf die Hydratierung von Kalziumchlorosilikat untersucht.

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, , .

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C=CaO, S=SiO₂, H=H₂O     

Influence of sodium on the catalytic properties of bismuth-molybdenum oxide catalysts

In the ammoxidation of propylene, the presence of a normal NaBi(MoO₄)₂ phase in bismuth molybdenum oxide catalysts decreases the acrylonitrile yield due to its oxidation

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NaBi(MoO₄)₂ -- .

     

Diastereomeric Oxathia[n](1,1′)ferrocenophanes

Zusammenfassung Neue Oxathiaferrocenophane wurden durch Umsetzung von 1,1-Bis(hydroxymethyl)ferrocen mit Dithiolen dargestellt, welche Sauerstoff in den Alkylketten enthalten. Die Reaktion von 1,1-Bis(-hydroxyethyl)ferrocenen mit Dithiolen führte zu Mischungen von Diastereomeren, aus welchen reine Stereoisomere isoliert und charakterisiert wurden. Einige Aspekte des stereochemischen Verlaufes dieser Reaktionen werden diskutiert.

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Diastereomere oxathia[n](1,1)ferrocenophane

Novel oxathiaferrocenophanes have been synthesized by the reaction of 1,1-bis(hydroxymethyl)ferrocene with dithiols bearing oxygen in chains. The reactions of 1,1-bis(-hydroxyethyl)ferrocenes with dithiols afforded mixtures of diastereomeric products from which pure stereoisomers were isolated and characterized. Some aspects concerning a stereochemical course of the reactions described are discussed.

     

Contribution to the kinetics of the process of dissolution

Some characteristics of the kinetic equation of dissolution are discussed, bearing in mind that in the course of the process, along with the concentration of the solution, the surface of the soluble substance is also changed. The opportunity for the appication of an exponential kinetic equation is pointed out. Methods are proposed for calculating the solubility and also for using the integral forms of the exponential equation. The meaning of the coefficient of proportionality is explained.

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