Thermoanalytical investigations of thallous nitrate

Thallous nitrate was investigated using TG, DTA, and DSC in conjunction with gas chromatography and X-ray diffraction analysis. TG showed a weight loss beginning at 380° with a 50 percent loss by 520°. This weight loss was demonstrated to be caused by boiling rather than thermal decomposition. The DTA extrapolated onset temperature for the boiling was 467°. Two solid-solid transition points and the melting point were determined by DTA to be 77, 145, and 207°, respectively. Heat of transition values determined by DSC were 0.15 kcal/mole at 77°, 0.87 kcal/ mole at 145°, and 2.18 kcal/mole for the melting at 207°.

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Zusammenfassung Thallium(I)nitrat wurde mittels TG, DTA und DSC, mit Gaschromatographie und Röntgendiffraktionsanalyse gekoppelt, untersucht. TG zeigte einen beginnenden Gewichtsverlust ab etwa 380° und einen Verlust von 50% bis 520°. Es wurde gezeigt, daß dieser Gewichtsverlust eher vom Sieden als von der thermischen Zersetzung verursacht wird. Die aus DTA-Daten extrapolierte Anfangs-Siedetemperatur war 467°. Die Fest-festphasen Übergangspunkte und der Schmelzpunkt lagen, wie durch DTA ermittelt, bei 77, 145, bzw. 207°. Die mittels DSC bestimmten Wärmen der Übergangswerte betrugen 0.15 kcal/Mol bei 77°, 0.87 kcal/Mol bei 145° und 2.18 kcal/Mol für das Schmelzen bei 207°.

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Résumé On a étudié le nitrate de thallium(I) par TG, ATD et DSC conjointement à la Chromatographie en phase gazeuse et à l'analyse par diffraction des rayons X. La TG révèle une perte de masse à partir d'environ 380°, avec une perte de 50 p. c. à 520°. On montre que cette perte de masse est provoquée par l'ébullition plutôt que par la décomposition thermique. La température initiale de l'ébullition, extrapolée à partir des données ATD, est de 467°. Deux points de transition solide-solide ainsi que le point de fusion ont été déterminés par ATD et correspondent aux températures respectives de 77, 145 et 207°. Les valeurs des chaleurs de transition ont été déterminées par DSC: 0.15 kcal, mol^–1 à 77°, 0.87 kcal. mol^–1 à 145 et 2.18 kcal. mol^–1 pour la fusion à 207°.

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, , - . , 380° 50% 520°. , , . 467°. - , , 77, 145 207°. , , 0.15 / 77°, 0,87 / 145° 2.18 / 207°.

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The authors thank F. J. Conrad and W. J. Andrzejewski for gas analysis results and G. T. Gay for X-ray diffraction analyses.This work was supported by the United States Department of Energy.     

Fusion entropy and melt viscosity in some aliphatic hydrocarbons. Relation between fusion entropy and parameterb of the Batchinski equation

The fusion entropy, viscosity and molar volume are measured for the following hydrocarbons: C₁₈H₃₈, C₁₉H₄₀, C₂₀H₄₂ and C₂₀H₄₀. A relation betweenS _fus and the parameterb of the Batchinski equation is given for these compounds and for others previously studied. By employing the calorimetric and viscometric data found in the literature for ionic melts, a similar relation is found to hold for molten salts.

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Zusammenfassung Die Schmelzentropie, die ViskositÄt und das Molvolumen wurden für folgende Kohlenwasserstoffe gemessen: C₁₈H₃₈, C₁₉H₄₀, C₂₀H₄₂, C₂₀H₄₀. Eine Korrelation zwischenS_fus und dem Parameterb der Gleichung von Batchinski wird für diese sowie für andere früher untersuchte Verbindungen vorgeschlagen. Durch Verwendung der kalorimetrischen und viskosimetrischen Literaturangaben für geschmolzene ionische Produkte wurde eine analoge Korrelation für geschmolzene Salze vorgeschlagen.

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Résumé L'entropie de fusion, la viscosité et le volume molaire des hydrocarbures C₁₈H₃₈, C₁₉H₄₀, C₂₀H₄₂ et C₂₀H₄₀ ont été mesurés. Une relation entre l'entropie de fusion,H_fus, et le paramètreb de l'équation de Batchinski est proposée pour ces composés et pour d'autres, précédemment étudiés. En utilisant les données calorimétriques et viscosimétriques trouvées dans la littérature pour les produits ioniques fondus, une relation analogue est proposée pour les sels fondus.

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, : C₁₈H₃₈, C₁₉H₄₀ C₂₀H₄₂ C₂₀H₄₀. , , S. b . , , , .

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Thanks are due to the C.N.R. (Rome) for financial aid.     

Influence of some organic acids on the adsorption of PdX42? complexes on alumina

Results are presented concerning the role of oxalic acid, salicylic acid and glycine as coimpregnation ingredients in preparation of Pd/Al₂O₃ catalysts from PdCl ₄ ^2– and PdBr ₄ ^2– solutions.

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, , , Pd/Al₂O₃ PdCl ₄ ^2– PdBr ₄ ^2– .

     

Determination of metal dispersity of Pd/SiO2 catalysts by transmission electron microscopy and H2?O2 chemisorption

Dispersity of palladium for a series of Pd/SiO₂ catalysts has been determined by TEM and H₂–O₂ chemisorption. The mean crystallite dimensions obtained by these methods have been compared. Assuming O/Pd_s to be 0.6 for Pd crystallites larger than 9 nm, good agreement has been observed between the results of the two experimental methods.

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Pd/SiO₂ H₂–O₂. , . O/Pd_s0.6, Pd 9 , .

     

Syntheses and properties of mixed dinuclear copper(II) complexes with heterocyclic dithiocarbamates and a cyclic octadentate tertiary amine

Five new Cu^II complexes of general formula [Cu₂(Rdtc)tpmc](ClO₄)₃, (1)–(5), where tpmc and Rdtc ^– refer to N,N,N,N-tetrakis(2-pyridylmethyl)-1,4,8,11-teraazacyclotetradecane and piperidine- (Pipdtc), 4-morpholine- (Morphdtc), 4-thiomorpholine- (Timdtc), piperazine- (Pzdtc) or N-methylpiperazine- (N-Mepzdtc) dithiocarbamates, respectively, have been prepared. Elemental analyses, conductometric and magnetic measurements, u.v./vis, i.r., e.p.r. and mass spectroscopy have been employed to characterize them. The complexes adopt an exo coordination of Cu^II ions and tpmc. The dithiocarbamate ion joins both the sulphur and the copper atoms acting as a bridging ligand The presence of different heteroatoms in the piperidine ring influences the (C=N) and (C=S) vibrations which decrease in the order of the complexes: Pipdtc>N-Mepipdtc>Pzdtc>Morphdtc>Timdtc ligands. Attention has been paid to the detailed mechanism of the mass spectral fragmentation of the complexes. The g _eff factors of the complexes have been also estimated by e.p.r. spectra. Finally, the complexes obtained demonstrate microbiologycal activity against some bacteria.     

Chromium (III) trihalide complexes of 4-aminobenzophenone

Summary The following chromium(III) complexes of 4-aminobenzophenone have been prepared and investigated by infrared and electronic spectra and magnetic susceptibility measurements: CrCl₃L, CrCl₃L₂ (pink and brown), CrCl₃L₃, CrCl₃L₆, CrBr₃L₂, CrBr₃L₃, CrBr₃L₄, CrBr₃L₆, CrBr₃L₇ and CrBr₃L₈. The CrBr₃ complexes were each isolated in a yellow and a red form. In the red CrBr₃ and in the yellow CrBr₃L₂ the ligand is bonded through the amine nitrogen. The CrCl₃ complexes are probably molecular complexes.     

Kinetics and mechanism of KBrO3 oxidation of D(+) xylose in acidic medium

KBr₃ oxidation of xylose, in presence of H₂SO₄, follows first order kinetics in [KBrO₃] and [xylose], and second order in [H₂SO₄]. The acid-catalyzed reaction gives aldonic acid as product. A mechanism consistent with temperature, solvent, higher acidity and salt effects has been proposed. Thermodynamic constants have been calculated.

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KBrO₃ H₂SO₄ [KBrO₃] [] [H₂SO₄]. - . , , , . .

     

Triterpene glycosides ofHedera canariensis. I. Structures of glycosides L-A,L-B1, L-B2, L-C,L-D,L-E1 1, L-G1, L-G2, L-G3, L-G4, L-H1, L-H2, AND L-I1 from the leaves ofHedera canariensis

From the leaves of Algerian ivyHedera canariensis Willd. (fam. Aralaceae) we have isolated 13 triterpene glycosides: the 3-O--L-arabinopyranosides of oleanolic acid (A), of echinocystic acid (B₁), and of hederagenin (B₂); the 3-O-[O--L-rhamnopyranosyl-(2)--L-arabinopyranoside]s of oleanolic acid (C), of echinocystic acid (D), and of hederagenin (E₁); the 3-O--L-rhamnopyranoside] 28-O-[O--L-rhamnopyranosyl-(14)--gentiobioside of hederagenin (G₁); the 3-O-[O--L-rhamnopyranosyl-(12)--L-arabinopyranoside] 28-O--gentiobioside of hederagenin (G3); the 3-O-[O--L-rhamnopyranosyl-(12)--L-arabinopyranoside] 28-O-[O--L-rhamnopyranosyl-(14)--gentiobioside]s of oleanolic acid (G₂), of echinocystic acid (H₁), and of hederagenin (H₂); the 3-O-[O--L-rhanmopyranosyl-(12)--D-glucopyranoside] 28-O-(O--L-rhamno-pyranosyl-(14)--gentiobioside] of hederagenin (H₂); and the 3-O-(O--L-rhamnopyranosyl-(12)-O-gentiobiosyl)-O-(14)--L-rhamnopyranosyl-(12)-a-L-arabinopyranoside] of hederagenin (G₄). The structures of the substances isolated have been established on the basis of chemical transformations and¹³C NMR spectroscopy.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 377–383, May–June, 1996. Original article submitted December 3, 1995.     

Coupling of thermometric titrimetry and constant-current coulometry: Study and applications

Two systems involving the coupling of thermometric and coulometry are presented. In the first assembly, the two electrodes were in the same compartment. Bromocoulometry was used to test the possibilities of this coupling in the sequential titration of a vitamin C+ aspirin mixture about (10^–4 M) and the determination of enthalpy changes. In a second coupling system, the anodic and cathodic compartments were separated by a sintered-glass disc of porosity 3. The conditions for obtaining an electrochemical cell which is also a good calorimeter are discussed. Examples of applications are given, such as analytical measurements, the study of an electrochemically catalysed reaction and of the thermal effects of electrode reactions.

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Zusammenfassung Zwei Systeme werden beschrieben, die eine Kombination von thermometrischer Titrimetrie und Coulometrie darstellen. Bei der ersten Vorrichtung sind die Elektroden im gleichen Raum Untergebracht. Die Bromocoulometric wurde zur Testung der durch diese Kombination für die aufeinanderfolgende Titration von Vitamin C/Aspirin Gemischen (ungefähr 10^–4 M) und für die Bestimmung der Enthalpieänderungen gebotenen Möglichkeiten angewandt. In einem zweiten kombinierten System waren Anoden- und Kathodenraum durch ein Sinterglasfilter der Porosität 3 voneinander getrennt. Es werden die Bedingungen diskutiert, die notwendig sind, um eine elektrochemische Zelle zu erhalten, die zugleich auch ein gutes Kalorimeter ist. Anwendungsbeispiele sind angegeben, wie analytische Messungen und elektrochemische Untersuchungen katalysierter Reaktionen oder thermischer Effekte von Elektrodenreaktionen.

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, . . — 10^–4 M . — N^o3. , . , , .

     

Design and application of a liquid-flow adsorption micro calorimeter based on the Calvet-type DAK 1-1 microcalorimeter (USSR)

The construction and the properties of a liquid-flow adsorption microcalorimeter are described. The calorimeter is based on the commercially available Calvet-type DAK 1-1 microcalorimeter (USSR), which has been equipped with a flow system consisting of a pump, several sets of heat exchangers and an adsorption cell. The minimum detectable heat effect is 1W up to a flow rate of 30 cm³/h.Results on the application of the calorimeter to adsorption and desorption processes of nonionic (Triton X-100) and anionic (styrene phosphonic acid) surfactant solutions in water at an-Al₂O₃ surface are presented and discussed.

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Zusammenfassung Konstruktion und Eigenschaften eines Flüssigkeits-Strömungs-Adsorptions-Mikrokalorimeters werden beschrieben. Das Kalorimeter wurde weiterentwickelt aus dem Calvet-Mikrokalorimeter DAK 1-1 (USSR), das mit einem Strömungssystem aus einer Pumpe, verschiedenen Wärmeaustauschern und einer Adsorptionszelle ausgestattet wurde. Der kleinste nachweisbare Wärmeeffekt liegt bei 1W bis zu einer Durchflussgeschwindigkeit von 30 cm³ h^–1. Mit dem Kalorimeter erhaltene Messergebnisse zur Adsorption und Desorption wässeriger Lösungen von nichtionischen (Triton X-100) und anionischen (Styrenphosphonsäuren) Tensiden an-Al₂O₃ werden dargestellt und diskutiert.

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, 1-1 (), , , . 1 30 ³/. ( X–100) (- ) -l₂₃.

     

Kinetics and mechanism of acetylene hydromethylation on organonickel catalysts

Kinetics of methane interaction with acetylene on Ziegler-Natta type organonickel catalysts has been studied. The reaction is first order with respect to methane. The kinetic isotope effect amounts to K_{CH 4}/K_{CD 4}=1.5 and K_{C 2}H₂,CH₄,H₂/K_{C 2}D₂,CD₄,D₂=2.0.

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-. -. K_{CH 4}/K_{CD 4}, K_{C 2}H₂,CH₄,H₂/K_{C 2}D₂,CD₄,D₂ 1,5; 2,0. .

     

Preparation of cobalt doped γ-Fe2O3 and Mn-Zn ferrites by the thermal decomposition of the hydrazine precursors

Fine particle cobalt doped-Fe₂O₃ and Mn-Zn ferrites have been prepared by the thermal decomposition of N₂H₅Co _x Fe_1–x (N₂H₃COO)₃.H₂O wherex=1–10 atom% and (N₂H₅)₃Mn_xZn_1–x Fe₂(N₂H₃COO)₉· 3H₂O wherex=0.2–0.8, respectively. Formation of these oxide materials has been confirmed by thermogravimetry and X-ray powder diffraction patterns. The fine particle nature of these oxide materials is evident from particle size analysis and surface area measurements.

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Zusammenfassung Mit fein verteiltem Kobalt versetztes-Fe₂O₃ sowie Mn-Zn Ferrite wurden durch thermische Zersetzung von N₂H₅Co _x Fe_1–x (N₂H₃COO)₃·H₂O mit jc=1–10 Atomprozent bzw. (N₂H₅)₃Mn _x Zn_1–x Fe₂(N₂H₃COO)₉·3H₂O mitx=0,2–0,8 hergestellt. Die Bildung dieser Oxidstoffe wurde durch Thermogravimetrie und Pulverdiffraktionsmethoden bekräftigt. Die Feinkornstruktur dieser Oxidstoffe wird durch Korngrößenverteilungs- und Oberflächenmessungen augenscheinlich.

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N₂H₅Co _x Fe_1–x (N₂H₃COO)₃·H₂O, x-1–10 %, (N₂H₅)₃Mn _x Zn_1–x Fe₂(N₂H₃COO)₉ · 3H₂O, x=0,2–0,8, , , -Fe₂O₃ Mn-Zn . . .

     

The simplest catalytic mechanism permitting several steady states of the surface

The conditions for the existence of several steady states of the surface have been found for the simplest mechanism without the assumption of autocatalysis and without the effect of the medium on the catalyst. A possibility has been shown for the explanation of the multiplicity of steady states, found experimentally in the kinetic region, in terms of mechanisms including interactions between various intermediates.

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. , , , .

     

Thermal decomposition of the addition compound of potassium carbonate with hydrogen peroxide

The kinetics of the thermal decomposition of the addition compound of potassium carbonate with hydrogen peroxide was carried out using a fixed bed flow reactor with gas-chromatography. The experimental results can be best represented over the whole range of the decomposition, by the equation-In (1–)=kt, where=degree of decomposition,t=time (min.), andk=rate constant (min.^–1). The activation energy and the pre-exponential factor for 0<<0.8, are 74.3 kJ/mol and 7.8 · 10⁹, and for the decay period (0.8<<1.0), 77.3 kJ/mol and 1.38 · 10¹⁰, respectively.

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Zusammenfassung Die Kinetik der thermischen Zersetzung der Additionsverbindung von Kaliumcarbonat mit Wasserstoffperoxid wurde unter Anwendung eines Fixbett-Durchfluß-reaktors durch Gaschromatographie untersucht.Die Versuchsergebnisse können im ganzen Bereich der Zersetzung am besten durch die Gleichung (I) -ln (1–)=kt beschrieben werden;=Zersetzungsgrad,t=Zeit (min) undk=Geschwindigkeitskonstante (min^–1).Die Aktivierungsenergie und der präexponentielle Faktor betragen, für 0<<0.8, 74.3 kJ/Mol, bzw. 7.8 · 10⁹ und für die Periode des Abklingens (0.8<<1.0) 77.3 kJ/Mol, bzw. 1.38 · 10¹⁰.

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Résumé On a étudié, par chromatographie en phase gazeuse, la cinétique de la décomposition thermique du composé d'addition du carbonate de potassium avec de l'eau oxygénée, en se servant d'un réacteur à écoulement, type lit fixe.Les résultats expérimentaux peuvent être décrits avec un bon ajustement dans tout l'intervalle de décomposition, par l'équation (I) -ln (1–)=kt;=degré de décomposition,t=temps (min) etk=constante de vitesse (min^–1).L'énergie d'activation et le facteur préexponentiel sont pour 0<<0.8, respectivement égaux à 74.3 et 7.8 · 10⁹ kJ/mole, et pour la période d'amortissement (0.8 <<1.0) à 77.3 et 1.38 · 10¹⁰ kJ/mole.

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, . -ln(1–)=t, - ,t- ( .) - (.^–1). 0<<0.8, , 74.3 / 7.8. 10⁹, (0.8<<1.0) —77.3 / 1.38. 10¹⁰.

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The authors wish to express their appreciation to Dr. D. Dollimore for his valuable comments and thank Mr. H. Nakamura, Research Fellow, Department of Environmental Engineering, Kyushu Institute of Technology, for his advise.     

Synthesis,physico-chemical and biological studies on oxovanadium(IV) derivatives of mercaptotriazoles

Summary Complexes of 3-methyl- or 3-ethyl-4-amino-5-thiolato-1,2,4-triazole (LH) and its Schiff base derivatives with oxovanadium(IV), of the types [VOL₂(H₂O)], [VOL₂-(H₂O)] and [VOL(H₂O)₂] (where LH = Schiff bases derived from condensation of LH with benzaldehyde, 2-chlorobenzaldehyde, 4-methoxybenzaldehyde or acetophenone; LH₂ = Schiff bases derived from condensation of LH with salicylaldehyde or o-hydroxyacetophenone) have been prepared and characterized by elemental analyses, electrical conductance, magnetic moments and spectral data. The thermal behaviour of selected complexes was investigated by t.g., d.t.g. and d.s.c. techniques. The antifungal and antiviral activities of the Schiff bases and their corresponding complexes were also investigated.Author to whom all correspondence should be directed.     

Simulation of adsorption dynamics in adsorbent layers of short length. Estimation of the concentration region of validity of Zeldovich"s equality

The frontal adsorption dynamics with the convex adsorption isotherm at a stage of parallel transfer, was numerically simulated. The change with time in the mean adsorption values a _c in the adsorbent layers of short length L and corresponding concentrations c _L at the outlet from L was calculated. Zeldovich"s equality, which suggests that the ratio of c _L to a _c is equal to the ratio of the inlet fluid phase concentration to the amount adsorbed at equilibrium, is fulfilled at L 0 over the interval of relative concentrations from 10^–4 to 1. This indicates that Zeldovich"s equality is fulfilled as local at any limiting stage of mass transfer. The nonequilibrium dynamics of adsorption always has the finite L value at which the calculated c _L and a _c values approximately coincide with the a and c values of the equilibrium adsorption isotherm.     

Zusammenhang zwischen den K α-Satelliten-Linien und den Röntgenübergängen vom Typ K 1 L 1→L 2 bei den Elementen Neon,Natrium, Magnesium,Aluminium und Silizium

Zusammenfassung Für die Elemente Neon, Natrium, Magnesium, Aluminium und Silizium werden mit einem quantenmechanischen Variationsverfahren unter Verwendung einer minimalen STF-Funktionenbasis Röntgenübergänge vom Typ K ¹L¹L² berechnet und den K -Satellit-Linien , , ₃, ₃ and ₄ zugeordnet.

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Relation between K -Satellits and X-ray-transitions of the type K ¹ L ¹L ² for Ne, Na, Mg, Al and Si

STF-Calculations are reported for X-ray-transitions of the type K ¹L¹L² for Ne, Na, Mg, Al and Si. It is shown that these transitions are correlated with the K -satellits , , ₃, ₃ and ₄.

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Die Wellenfunktionen können auf Anfrage zur Verfügung gestellt werden.     

Nonisothermal kinetics of independent reactions

A general approach to the solution of peak seperation problem applicable not only in nonisothermal kinetics, but also in chromatographic, spectroscopic and polarographic studies of catalysts is suggested.

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, , , , , .

     

A differential scanning calorimetric study of some phenol derivatives

Differential scanning calorimetry has been applied to derive the fusion enthalpies and entropies of series of mono and dimethylphenols, mono and dichlorophenols, and mono and dinitrophenols.

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Zusammenfassung DSC wurde verwendet zur Ermittlung der Schmelzenthalpie und Entropie der Reihen von Mono- und Dimethylphenolen, Mono- und Dichlorphenolen, Mono- und Dinitrophenolen.

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- , - , - .