Triterpenoid Glycosides of Fatsia japonica. II. Isolation and Structure of Glycosides from the Leaves

The previously known triterpenoid 3-O--L-arabinopyranosides of oleanolic and echinocystic acids and hederagenin, 3-O--D-glucopyranosyl-(12)-O--L-arabinopyranosides of oleanolic acid and hederagenin, in addition to 28-O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl ethers of the 3-O--L-arabinopyranoside of hederagenin, and 3-O--D-glucopyranosyl-(12)-O--L-arabinopyranosides of oleanolic acid and hederagenin, respectively, are isolated from leaves ofFatsia japonica(Araliaceae). The structures of the glycosides are confirmed by chemical methods and ¹³ C NMR spectroscopy     

Generalized quantum mechanical two-centre problems. IV. On the accuracy of simple LCAO approximations for H 2 + states and the Eckart criterion

If x denotes an exact solution of the quantum mechanical two centre Coulomb problem, we optimize a normalized LCAO approximation by making the overlap S = (x¦) a maximum. In this context we study how a weight factor (r _a r _b )^–1 in the definition of the inner product changes the approximation and the expectation value of electronic energy. Finally we compare the lower bound given by the Eckart criterion with the exact overlap. Results are reported for H ₂ ⁺ states 1s_g and 2p_u.Dedicated to Professor Hermann Hartmann on occasion of his 70th birthday on May 4th, 1984     

The effect of alkyl groups on the electronic spectra of benzenoid hydrocarbons

Alkyl substitution of benzenoid hydrocarbons shifts their ¹ L band to longer wavelengths. A statistical analysis of the available data for naphthalene, phenanthrene and 1,2-benzanthracene indicates that simple Hückel theory does not yield as good a prediction for these shifts as has previously been assumed. It is shown that a significant improvement results if many electron wavefunctions are used and if mixing between the configurations ₁ ^–1 and ₂ ^–2 is introduced.

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Zusammenfassung Unter dem Einfluß von Alkylsubstituenten verschiebt sich die ¹ L Bande aromatischer Kohlenwasserstoffe nach längeren Wellenlängen. Eine statistische Analyse der Daten für Naphthalin, Phenanthren und 1,2-Benzanthracen deutet darauf hin, daß das einfache Hückelsche Verfahren weniger gute Voraussagen dieser Verschiebungen liefert, als allgemein angenommen wird. Es kann gezeigt werden, daß die Verwendung von Mehrelektronen-Wellenfunktionen und die Einbeziehung der Wechselwirkung zwischen den Konfigurationen ₁ ^–1 und ₂ ^–2 einer signifikanten Verbesserung der Voraussagen führt.

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Résumé L'introduction d'un groupe alkyle sur un hydrocarbure benzènoïde provoque un déplacement de la bande ¹ L vers les grandes longueurs d'onde. Une analyse statistique des données existant pour le naphthalene, le phénanthrène et le 1,2-benzanthracène montre que la simple théorie de Hückel ne permet pas de prévoir ce déplacement aussi exactement qu'on l'admet en général. L'utilisation de fonctions d'onde polyélectroniques et l'introduction de l'interaction entre les configurations ₁ ^–1 et ₂ ^–2 conduit, au contraire, à une amélioration significative des résultats.

     

Thermal properties of pentavanadates

The thermal properties of K₃V₅O₁₄,Rb₃V₅O₁₄ and Tl₃V₅O₁₄ were studied in the temperature range 20–1000 in air atmosphere using DTA. K₃V₅O₁₄, is the most stable pentavanadate. Tl₃V₅O₁₄ is thermally stable up to 360; at higher temperature it decomposes to TlVO₃ and Tl₂V₆O₁₆. Rb₃V₅O₁₄ is stable up to 300 at higher temperature it decomposes to RbVO₃ and Rb₂V₆O₁₆, and at even higher temperature Rb₂V₆O₁₆, reacts with part of the RbVO₃ and Rb₂V₄O₁₁ is formed.

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Zusammenfassung Die thermischen Eigenschaften von K₃V₅O₁₄, Rb₃V₅O₁₄ und T1₃V₅O₁₄ wurden im Temperaturbereich von 20 bis 1000 in Luft durch DTA untersucht. K₃V₅O₁₄ ist das stabilste Pentavanadat. Tl₃V₅O₁₄ ist thermostabil bis zu 360; bei höheren Temperaturen wird es zu TlVO₃ und Tl₂V₆O₁₆ zerstetzt. Rb₃V₅O₁₄ ist bis zu 300 stabil, bei höheren Temperaturen wird es zu RbVO₃ und Rb₂V₆O₁₆ zersetzt und bei noch höheren Temperaturen reagiert Rb₂V₆O₁₆ mit einem Teil des RbVO₃ zu Rb₂V₄O₁₁.

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Résumé On a étudié les propriétés thermiques de K₃V₅O₁₄, Rb₃V₅O₁₄ et Tl₃V₅O₁₄ par ATD entre 20 et 1000 dans l'air. K₃V₅O₁₄ est le pentavanadate le plus stable. Tl₃V₅O₁₄ est thermiquement stable jusqu'à 360; à des températures plus élevées il se décompose en TlVO₃ et Tl₂V₆O₁₆ · Rb₃V₅O₁₄ est stable jusqu'à 300; à des températures plus élevées il se décompose en RbVO₃ et Rb₂V₆O₁₆ et à des températures encore plus élevées, Rb₂V₆O₁₆ réagit avec une partie du RbVO₃ et il se forme Rb₂V₄O₁₁.

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K₃V₅O₁₄,Rb₃V₅O₁₄ Tl₃V₅O₁₄ 20– 1000 . K₃V₅O₁₄ . Tl₃V₅O₁₄ 360, TlVO₃ Tl₂V₆O₁₆. Rb₃V₅O₁₄ 300, RbVO₃ Rb₂V₆O₁₆. RbVO₃ Rb₂V₄O₁₁.

     

Possibilities of applying the Piloyan method of determination of decomposition activation energies in the differential thermal analysis of polynitroaromatic compounds and their derivatives

The Piloyan activation energiesE, as well as the initial exotherm temperaturesT _D, are determined for sixN-monoalkyl- and fiveN,N-dialkyl-2,4,6-trinitroanilines. By comparison withR _f-factors, orR _M-functions of paper chromatography, the molecular-structural dependences ofE andT _D are studied for these compounds. Relationships are also found between the termE · T _D ^–1 and theR _M-functions. The effects are discussed of the introduction of the 6-nitro group into the TV-substituted 2,4-dinitroanilines, and of the introduction of the 4-nitro group into the 2,6-dinitro analogues, upon the thermal stabilities of the resulting 2,4,6-trinitroanilines.

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Zusammenfassung Die AktivierungsenergienE nach Piloyan und die Anfangswerte der ExothermenT _D der sechsN-monoalkyl- und fünfN,N-Dialkyl-2,4,6-trinitroaniline wurden bestimmt. Unter Berücksichtigung des Vergleichs mitR _f-Faktoren oderR _M-Funktionen der Papierchromatographie wurden die molekularstrukturellen AbhÄngigkeiten der WerteE undT _D dieser Verbindungen untersucht. ZusammenhÄnge wurden auch zwischen dem AusdruckE · Tw _D ^–1 und denR _M-Funktionen gefunden. Der Einfluss der Einführung der 6-Nitrogruppe in dieN-substituierten 2,4-Dinitroaniline, sowie der Einfluss der Einführung der 4-Nitrogruppe in 2,6-Nitroanaloge auf die ThermostabilitÄt der resultierenden 2,4,6-Trinitroaniline werden erörtert.

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Résumé On a déterminé les énergies d'activation par la méthode de Piloyan ainsi que les températures initialesT _D de l'effet exothermique de sixN-monoalcoyl- et cinqN,N-dialcoyl-2,4,6-trinitroanilines. En se référant aux facteursR _F ou aux valeurs des fonctionsR _M en Chromatographie sur papier, on a étudié la dépendance entre les valeurs deE et deT _D sur les caractéristiques moléculaires-structurales de ces composés.On a également trouvé des rapports entre le termeE · T _D ^–1 et les fonctionsR _M. On discute l'influence de l'introduction du groupe 6-nitro dans les 2,4-dinitroanilinesN-substituées ainsi que l'influence de l'introduction du groupe 4-nitro dans les 2,6-dinitro analogues sur la stabilité thermique des 2,4,6-trinitroanilines qui en résultent.

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N-- N,N--2,4,6- E , T _D. R _f,- R _M — , - E T _D. E.T _D ^–1 R _M-. 6N- 2,4- 4 2,6- 2,4,6- .

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The authors would like to thank Mrs. Anna Colláková for careful DTA measurements, and Dr. Ladislav Smolka for help in the treatment of the measured results with the Wang 600 computer.     

On the Interaction of Two Finite-Dimensional Quantum Systems

Interaction of quantum system S ^a described by the generalised × eigenvalue equation A| _s =E _s S ^a | _s (s=1,...,) with quantum system S ^b described by the generalised n×n eigenvalue equation B| _i = _i S ^b | _i (i=1,...,n) is considered. With the system S ^a is associated -dimensional space X ^a and with the system S ^b is associated an n-dimensional space X _n ^b that is orthogonal to X ^a . Combined system S is described by the generalised (+n)×(+n) eigenvalue equation [A+B+V]| _k = _k [S ^a +S ^b +P]| _k (k=1,...,n+) where operators V and P represent interaction between those two systems. All operators are Hermitian, while operators S ^a ,S ^b and S=S ^a +S ^b +P are, in addition, positive definite. It is shown that each eigenvalue _{k i} of the combined system is the eigenvalue of the × eigenvalue equation . Operator in this equation is expressed in terms of the eigenvalues _i of the system S ^b and in terms of matrix elements _s |V| _i and _s |P| _i where vectors | _s form a base in X ^a . Eigenstate | _k ^a of this equation is the projection of the eigenstate | _k of the combined system on the space X ^a . Projection | _k ^b of | _k on the space X _n ^b is given by | _k ^b =( _k S ^b –B)^–1(V– _k P})| _k ^a where ( _k S ^b –B)^–1 is inverse of ( _k S ^b –B) in X _n ^b . Hence, if the solution to the system S ^b is known, one can obtain all eigenvalues _{k i} } and all the corresponding eigenstates | _k of the combined system as a solution of the above × eigenvalue equation that refers to the system S ^a alone. Slightly more complicated expressions are obtained for the eigenvalues _{k i} } and the corresponding eigenstates, provided such eigenvalues and eigenstates exist.     

Ligand exchange between bis-acetylacetonato cobalt(II) and organotin compounds SnR2Cl2 (R=Ph, Et), II. Mechanism of ligand exchange between acetylacetonate complexes of Co(II)

Ligand exchange between the compounds Co(AA)₂Py₂ and Co(AA)Clpy_x (x=1 or 3) formed in the, system, CO(AA)₂–SnR₂Cl₂(R=Ph, Et) in chloroform with pyridine has been established to be catalyzed by SnR₂Cl₂. An interpretation of the catalytic action of SnR₂Cl₂ is suggested.

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, Co(AA₂py₂ Co(AA)Clpy_x (x=1 3) (Co(AA)₂–SnR₂Cl₂ (R=Ph, Et) , SnR₂Cl₂. SnR₂Cl₂.

     

Thermal membrane potential across cation-exchange membranes for various halide solutions

Thermal membrane potential across cation-exchange membranes was measured for various halide solutions. Linear relationships between thermal membrane potential () and temperature difference (T) were observed, and the temperature coefficient of thermal membrane potential (/T) decreases with increase in the molality of the external solution as predicted by a theory reported. When counterions of membranes are hydrogen ions, the sign of the coefficients turns into minus near 0.01 mol/kg of the external solution for all membranes, although the coefficients are always positive for all the other forms. The dependence of the coefficients on the molality of the external solutions sometimes deviated slightly from the theory. This deviation is attributed to some change in water content of the membranes. A reproducible method of measuring water content of membranes was applied to discuss the change in the state of the membranes.     

Hypervirial theorems and symmetry

It is pointed out that to ensure that an optimal variational wave function having a certain symmetry satisfies the hypervirial theorem forW, it is sufficient thatiSW, whereS is the projector onto the symmetry type in question, be a possible variation of . Application is made to the tensor hypervirial theorem for atoms.     

Thermal stability of pure and lithium intercalated non-stoichiometric V6O13

V₆O_13+y has been prepared by thermal decomposition of NH₄VO₃. Lithium intercalated Li_xV₆O_13+y (1 X 6.0) specimens have been obtained by room temperature lithiation of V₆O_13+y withn-butyl lithium. Thermal stability of the compounds has been investigated by heating them in an argon atmosphere. The sequence of transformations has been studied by thermal analysis and X-ray diffraction measurements. The thermal curves of both V₆O_13+y and Li_xV₆O_13+y are characterized by several endo- and exothermic peaks and are quite complex in nature. Pure V₆O_13+y on heating in an argon atmosphere, oxidizes to V₃O₇ and V₂O₅ and this is associated with a broad exothermic peak around 340 °C. The two endothermic peaks at 675 °C and 710 °C are due to the melting of V₃O₇ and V₆O_13+y respectively. The compounds Li_xV₆O_13+y, on heating, partly transforms to a mixture ofv-LiV₂O₅ and VO₂ accompanied by considerable oxygen loss. The extent of this conversion increases with increasing lithium content of the starting compound.

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Zusammenfassung V₆O_13+y wurde durch thermische Zersetzung von NH₄VO₃ hergestellt. Eingelagertes Lithium enthaltende Li_xV₆O_13+y-Proben (1 x 6.0) wurden durch Behandlung von V₆O_13+y mitn-Butyl-lithium bei Raumtemperatur erhalten. Die thermische Stabilität dieser Verbindungen wurde durch Erhitzen in Argonatmosphäre ermittelt. Die aufeinanderfolgenden Umwandlungen wurden durch thermische Analyse und Röntgendiffraktometrie untersucht. Die thermischen Kurven von V₆O_13+y sind ziemlich komplex und zeigen einige charakteristische endo- und exotherme Peaks. Reines V₆O_13+y oxydiert sich beim Erhitzen in einer Argonatmosphäre zu V₃O₇ und V₂O₅. Dieser Prozeß geht mit einem breiten exothermen Peak bei 340° einher. Die zwei endothermen Peaks bei 675 und 710° sind dem Schmelzen von V₃O₇ bzw. V₆O_13+y zuzuschreiben. Die Verbindungen Li_xV₆O_13+y gehen beim Erhitzen unter beträchtlichem Sauerstoffverlust teilweise in ein Gemisch vonv-LiV₂O₅ und VO₂ über. Das Ausmaß dieser Umwandlung steigt mit dem Lithiumgehalt des Ausgangsmaterials an.

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NH₄VO₃ V₆O_{13+ y} . - Li _x V₆O_13+y 1x6. . - . V₆O_13+y Li _x V₆O_13+y . V₆O_13+y V₃O₇ V₂O₅, 340°. 675 710° , , V₃O₇ V₆O_13+y . Li _x V₆O_13+y v-LiV₂O₅ VO₂, . .

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The authors are grateful to Prof. A. Paul for his helpful suggestions. Partial financial support by the Electronics Commission, Govt. of India (Project No. 2/(106)/81-TDID(206)) is gratefully acknowledged.     

Hydrocondensation of CO: Catalytic activity of modified iron-alumina catalysts

The activity of modified Fe/Al₂O₃ catalysts in the hydrocondensation of CO has been studied in terms of the selectivity for light olefins and of repartition of the hydrocarbon products.

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Fe/Al₂O₃ CO, .

     

Oxidative conversion of butane and pentane on superacid catalysts

Catalytic properties of AlBr₃, AlBr₃–CuCl₂ and AlBr₃–NiSO₄ in liquid-phase conversion of butane and pentane have been examined. A possibility for the oxidative condensation has been revealed due to both the stoichiometric reduction of Ni²⁺ and Cu²⁺ ions entering into the composition of superacid catalysts, and the catalytic oxidation in the presence of bromine as an oxidant. Nature of the centers responsible for the oxidative condensation of lower paraffins is discussed.

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AlBr₃; AlBr₃–CuCl₂; AlBr₃–NiSO₄ . , Ni²⁺, Cu²⁺, , . , .

     

Basic condensation of triphenylsilane. II. Kinetics in anhydrous isopropanol and influence of silanol

Condensation of triphenylsilane with isopropanol in presence of isopropoxide has been studied in anhydrous medium and the activation parameters have been measured. Dehydration of the medium has been obtained by means of a pre-reaction of triphenylsilane with the residual water in the solvent. In this medium the reaction is extremely slow, moreover, it is inhibited by silanol whose effect would lower the actual catalyst concentration.

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. . , .

     

Crystallization of glasses in the system SiO2-Li2O-TiO2-Al2O3, investigated in situ at high temperature by XRD and DTA methods

The processes of crystallization of fibres (diameter 10–15m) and coarse powders (grain size 500–1000m) with four compositions in the system SiO₂-Li₂O-TiO₂-Al₂O₃ were studied by conventional and in situ high-temperature XRD, DTA, SEM and optical microscopy. Activation energies of crystallization and morphological indices were deduced from the kinetic curves obtained by recording the high-temperature XRD peak intensity as a function of time. The glass-ceramic fibres drawn from compositions which exhibit glass-inglass phase separation show prevailing not-oriented bulk crystallization, whereas prevailing surface crystallization was found for single-phase glass fibres. Homogeneously-dispersed crystallization was obtained on heating fibres of these compositions. The partially cocrystallized glass fibres of eutectic composition between Li-metasilicate and-spodumene gave rise to a very fine and homogeneously-dispersed sub-microstructure.

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Zusammenfassung Die Prozesse der Kristallisation von Fasern (Durchmesser 10–15m) und groben Pulvern (Korngröße 500–1000m) von SiO₂-LiO₂-TiO₂-Al₂O₃ in vier verschiedenen Zusammensetzungen wurden mittels herkömmlicher und in situ XRD, DTA, SEM und optischer Mikroskopie untersucht. Aktivierungsenergien der Kristallisation und morphologische Indices wurden aus den durch Registrierung der Intensität der Hochtemperatur-XRT-Peaks in Abhängigkeit von der Zeit erhaltenen kinetischen Kurven ermittelt. Die aus Gemischen einer die Glas-in-Glas-Phasentrennung bedingenden Zusammensetzung gezogenen Glas-Keramik-Fasern zeigen vorwiegend eine nicht-orientierte Bulk-Kristallisation, während vorherrschend Oberflächenkristallisation bei Einphasen-Glasfasern festgestellt wurde. Eine homogen verteilte Kristallisation wurde beim Erhitzen der Fasern dieser Zusammensetzungen erhalten. Bei partiell ko-kristallisierten Glasfasern einer eutektischen Mischung von Li-Metasilikat und (-Spodumen liegt eine sehr feine und homogen-disperse Submikrostruktur vor.

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( 10–15 ) ( 500–1000 ) SiO₂-Li₂O-iO₂AL₂O₃ , , . , - . , --, ë, - . - . — - - - .

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This work was supported by the Italian C. N. R., Progetto Finalizzato Chimica Fine e Secondaria — Sottoprogetto Metodologie.

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We are indebted to Dr. B. Locardi of Stazione Sperimentale del Vetro, Murano (Venice) for furnishing the initial glasses and fibres.

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We are also indebted to the G. Giacomello Institute (C. N. R., Rome) for furnishing the computer programme for the unit cell parameter refinement. Assistance by M. Pistolato and F. Venuda in the experimental work is gratefully acknowledged.     

Study of the solid solution of MoO3 in Fe2V4O13

Differential thermal and phase X-ray analyses have shown that MoO₃ and Fe₂V₄O₁₃ form a solid substitution solution, in which Mo⁶⁺ ions are incorporate into the crystal lattice of Fe₂V₄O₁₃ in place of V⁵⁺ ions. The solubility limit of MoO₃ in Fe₂V₄O₁₃ at ambient temperature is 18 mole % of MoO₃. The phase equilibria in the system Fe₂V₄O₁₃-FeVMoO₇, were also studied. Results are presented in the form of a phase diagram.

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Zusammenfassung Durch DTA und Röntgenphasenanalyse wurde gezeigt, daß MoO₃ und Fe₂V₄O₁₃ Substitutionsmischkristalle bilden, in denen Mo⁶⁺-Ionen anstelle von V⁵⁺-Ionen in das Kristallgitter von Fe₂V₄O₁₃ eingebaut sind. Die Löslichkeitsgrenze von MoO₃ in Fe₂V₄O₁₃ beträgt bei Umgebungstemperatur 18 Mol-% MoO₃. Ebenfalls wurden die Phasengleichgewichte im System Fe₂V₄O₁₃-FeVMoO₇ untersucht. Die Ergebnisse sind in Form eines Phasendiagramms dargestellt.

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- , ₃ Fe₂V₄O₁₃ , o⁶⁺ V^5– Fe₂V₄O₁₃. ₃ Fe₂V₄O₁₃ 18 %. Fe₂V₄O₁₃-FeVMoO₇ .

     

Formation of N-butane in the pyrolysis of ethylene [1]

Yields of n-C₄H₁₀ have been measured from the flow pyrolysis of C₂H₄ at 897 (±7) K. From 77 to 720 Torr the order of n-C₄H₁₀ formation was found to be 2.0±0.3 The rate constant for the reaction, was estimated to be 2.4(±0.6)×10^–4l mol^–1s^–1.

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-C₄H₁₀ C₂H₄ 897 (±7) . -C₄H₁₀ 77 720 2.0±0.3. 2C₂H₄C₂H₃+C₂H₅ 2,4 (±0,6)×10^{–4 –1–1}.

     

Ab initio studies of the low-lying π-states of borazine

Self-consistent-field and configuration-interaction studies were performed on borazine, using a double-zeta basis set augmented by six diffuse -functions. Low-lying singlet and triplet states of the A ₁ , A ₂ and E species were calculated, corresponding to ^* excited valence and Rydberg states. A selection out of singly and doubly excited configurations relative to a set of reference configurations was made for each species. Calculated vertical excitation energies (in eV) are 7.12 for ¹ A ₂(V), 8.45 for ¹ E (3p-R), 8.57 for ¹ A ₁(V), 8.9 for ¹ E(V-R), 9.55 for ¹ E(3d-R), 6.98 for ³ A ₁(_V), 7.27 for ³ E(V), 7.82 for ³ A ₂(V), 8.30 for ³ E(3p-R), and 9.5 for ³ E(3d-R), where V and R refer to valence or Rydberg character. The results are compared with experimental excitation energies, previous ab initio studies of borazine, and with recent ab initio studies of benzene.Dedicated to Professor Dr. H. Hartmann on the occasion of his 65th birthday.     

V2O5/TiO2 oxidation catalysts, III. Oxidation of CO on pure and sodium-doped systems

The activity of vanadia/titania catalysts in CO oxidation has been tested and found to be of the same order as that observed for unsupported vanadia; the simultaneous presence of vanadium-sodium compounds cancels the activity, probably because of the elimination of labile V=0 species at surface defects.

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V₂O₅/TiO₂ CO, V₂O₅; - , , V=0 .

     

Thermal decomposition of ammonium permanganate

The parent material, ammonium permanganate, was carefully decomposed in air at 120°. The product, referred to as the starting material (SM), was then subjected to thermal treatment in air for 5 hr in the temperature range 150–1200°. Chemical analysis of SM indicated that the main decomposition product of NH₄MnO₄ was Mn₂O₃, together with MnO₂, NH₄NO₃, H₂O and O₂. Mn₃O₄ started to form at 900°. The infrared spectra of various calcination products revealed the retention of NH ₄ ⁺ in the lattice structure up to 300°, and reflected the presence of excess oxygen as coordinated O ₂ ^– . The TG, DTA and IRA results on SM supported the chemical analysis data. X-ray analysis was carried out for phase identification and to follow transformations and the formation of a solid solution between MnO₂ and Mn₂O₃.

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Zusammenfassung Die Muttersubstanz, Aramoniumpermanganat, wurde in Luft bei 120° vorsichtig zersetzt. Das dabei erhaltene Ausgangsmaterial (SM) wurde danach in Luft 5 Stunden im Temperaturbereich von 150–1200° thermisch behandelt. Die chemische Analyse von SM ergab, daß als Hauptprodukt der Zersetzung von NH₄MnO₄, Mn₂O₃ auftritt neben MnO₂, NH₄NO₃, H₂O und O₂. Die Bildung von Mn₃O₄ beginnt bei 900°. Aus Infrarotspektren verschiedener Kalzinierungsprodukte ist ersichtlich, daß in der Gitterstruktur NH ₄ ⁺ bis 300° zurückgehalten wird und überschüssiger Sauerstoff in Form von koordiniertem O₂ vorliegt. Die Ergebnisse der TG-, DTA- und IRA-Untersuchungen von SM bestätigen Daten der chemischen Analyse. Mittels Röntgenanalyse wurden die Phasen identifiziert und der Verlauf der Phasenübergänge und der Bildung einer festen Lösung zwischen MnO₂ und Mn₂O₃ verfolgt.

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120°. , , 5 150–1200°. , , , , . 900° Mn₃O₄. 300° - O ₂ ^– . , . , .

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Paper presented at the World Conference on Thermal Analysis, Madeira (Portugal), 1986.