Infrared spectroscopy of hydrogen bond and substituent effects in electron donor molecules

The frequency shift, , of the O—H stretching mode in the IR spectra of the H-complexes of phenol with electron donor molecules BX_i (B is the n- or -donor center and X_i are substituents; a total of eight series), the change in the Gibbs free energy, G, due to H-complexation, and the parameter (a measure of the ability of BX_i molecules to donate an electron pair; two series) are determined by both the electrostatic interaction and charge transfer in the formation of H-complex. The , G, and values depend not only on the inductive and resonance effects, but also the polarizability of substituents characterized by the parameters.     

Le calcul des parametres cinetiques des Reactions de Decomposition thermique a l'aide des donnees de l'analyse thermique differentielle

Résumé On a modifié la méthode différentielle pour le calcul des paramètres cinétiques des réactions de décomposition thermique du type: A_(s) B_(s) + C_(g), en utilisant les données de l'analyse thermodifférentielle. En effectuant le calcul des paramètres cinétiques des réactions de déshydratation de l'oxalate de calcium monohydraté et de décomposition du carbonate de calcium on obtient des résultats qui concordent d'une manière satisfaisante avec ceux obtenus par d'autres méthodes.

---

A modification of the differential method is presented in order to evaluate the kinetic parameters of thermal decomposition reactions of the type A _s B _s + +C_g, using differential thermal analysis (DTA) data. The kinetic parameters calculated for the dehydration and decomposition of calcium oxalate and carbonate agree satisfactorily with those mentioned in the literature.

---

Zusammenfassung Es wird über eine Abänderung der Differentialmethode zur Errechnung der kinetischen Parameter von thermischen Zersetzungsreaktionen des Typs A_(s) B_(s) + C_(g) mit Hilfe von differentialthermoanalytischen Daten berichtet. Die am Beispiel der Dehydratation des Calciumoxalat-Monohydrats und der Zersetzung des Calciumcarbonats erhaltenen Ergebnisse der auf angegebene Weise durchgeführten kinetischen Berechnungen stimmen gut mit den nach anderen Methoden erhaltenen Resultaten überein.

---

A_{(s) (s)} + C_(g), (). , , , .

     

Acid properties and stability of operation of vanadium catalysts in benzene oxidation to phenol

Catalytic properties of V₂O₅/SiO₂ in benzene oxidation by N₂O were examined. Sodium additive was shown to affect the catalyst operation stability.

---

V₂O₅/SiO₂ N₂O. .

     

Alcohol formation from synthesis gas: A thermodynamic study

A thermodynamic study is presented for the simultaneous synthesis of C₁–C₄ alcohols from synthesis gas. The equilibrium composition was calculated for the gaseous mixture containing Co, H₂, CH₃OH, C₂H₅OH, C₃H₇OH, n-C₄H₉OH and H₂O. Operating industrial conditions were specifically considered.

---

C₁–C₄ -. , CO, H₂, CH₃OH, C₂H₅OH, C₃H₇OH, -C₄H₉OH H₂O. .

     

Kinetics of deuterium isotope exchange between thiophenol or t-butylthiol and i-propylthiol

The rate constants and activation energies of bimolecular deuterium exchange in the systems: C₅H₅SD+i-C₃H₇SH and t-C₄H₉SD+i-C₃H₇SH in dilute C₆H₁₂ solutions have been established. The concerted H-transfer inside the cyclic dimer with two H-bonds formed in these systems is probably the rate-limiting step. The rate constant for H-transfer inside the cyclic dimer is independent of the acidic properties of the thiols.

---

: C₆H₅SD+i-C₃H₇SH -C₄H₉SD+i-C₃H₇SH C₆H₁₂. -, , , . .

     

m-Xylene conversion over dealuminated Y zeolites studied by the pulse method

m-Xylene conversion was studied over dealuminated Y type zeolites in hydrogen forms, SiO₂ to Al₂O₃ ratios were varied from 4.86 to 12.95.

---

- . SiO₂/Al₂O₃ 4,86 12,95.

     

An Inorganic-Organic Hybrid Supramolecular Hydrogen-Bonding and π-π Stacking Network Containing Ge4S4− 10 Cluster: Synthesis and Characterization of (H2bipy)2Ge4S10⋅(bipy)⋅7H2O (bipy=4,4′-bipy)

The reactions of TMA₄Ge₄S₁₀ (TMA=tetramethylammonium), Cu(NO₃)₂3H₂Oand 4,4-bipy under hydrothermal environment result in the formation of (H₂bipy)₂Ge₄S₁₀(bipy)7H₂O (1), which has been structurally characterized by single crystal X-ray analysis. The 3-D structure of 1 can be viewed as an inorganic-organic hybrid supramolecular hydrogen-bonding (hydrogen bonds: O–HO, N–HN, C–HO, N–HO, and O–HS) and - stacking network containing Ge₄S^4– ₁₀ clusters and novel [H₂bipybipyH₂bipy] trimers.     

TG-DTA-MS Investigations of coal,and characterization of the volatile products released as a function of temperature

Coal samples containing 6.9% volatile matter (anthracite) have been investigated by use of a TG-DTA-MS technique. Estimation of the ash content, volatile matter (d.a.f.) and moisture is possible during one experiment. On running under ASTM conditions, separate tests have to be carried out. When the thermoanalytical curves were recorded in air, a particle diameter of 0.063 mm was most advantageous, because the heating of coal samples with a larger particle size at a heating rate of 10 deg/min^–1 caused explosion of the particles and the TG-DTA data was not reproducible. The mass fragments of the volatile products range fromm/z=16 tom/z=300 at a working pressure of approximately 10^–6 mbar in the mass spectrometer.

---

Zusammenfassung Kohleproben mit einem Gehalt an flüchtigen Bestandteilen von 6.9% w.a.f. wurden mit Hilfe simultaner Thermogravimetrie-Differenzthermoanalyse-Massenspektroskopie untersucht. Diese Untersuchungsmethode gestattet die Bestimmung des Aschegehaltes, der flüchtigen Bestandteile und der Feuchtigkeit in einem Experiment. Um diese Daten entsprechend der ASTM- (ISO)Bedingungen zu ermitteln, müssen separate Tests durchgeführt werden. Zur Ermittlung der DTA-Daten in Luft unter Normaldruck haben sich Proben mit einem Korndurchmesser von 0.063 mm als vorteilhaft erwiesen. Da durch Anwendung höherer Heizraten als 10 K min^/s-1 größere Teilchen explosionsartig zersetzt werden, sind die TG-DTA-Daten nicht mehr reproduzierbar. Die Massenbruchstücke der flüchtigen Bestandteile erstreckt sich vonm/z=16 bism/z=300 bei einem Druck von 10^–6 mbar im Massenspektrometer.

---

-- , 6,9% . , . , 0,063 , 10° -- . /=16–300 - 10^–6 .

     

Structure of vanadium phosphate anion in solutions from17O,51V and31P NMR data

¹⁷O,⁵¹V and³¹P NMR studies indicate that the anion structure of sodium vanadophosphate in an aqueous solution is close to that in crystals of the (CN₃H₆)₈HPV₁₄O₄₂ 7H₂O salt.

---

¹⁷O,⁵¹V,³¹P , (CN₃H₆)₈HPV₁₄O₄₂ 7H₂O.

     

The thermal decomposition of disodium propan-2-one-l,3-disulphonate

The thermal decomposition of disodium propan-2-one-1,3-disulphonate (NaO₃S.CH₂.CO.CH₂.SO₃Na) in atmospheres of both oxygen and nitrogen proceded by a complete molecular disruption with sodium sulphate or mixtures of sodium sulphate and sodium carbonate as the final residues. No organic compounds were detected in the volatile products.

---

Zusammenfassung Die thermische Zersetzung des Dinatriumpropan-2-on-l,3-disulfonats (NaO₃S.CH₂.CO.CH₂.SO₃Na) vollzog sich sowohl in Sauerstof-fals in Stickstoff-Atmosphäre unter vollständiger Zerstörung des Moleküls mit Natriumsulfat oder Mischungen von Natriumsulfat und Natriumcarbonat als Restprodukt. Unter den flüchtigen Produkten wurden keine organischen Verbindungen nachgewiesen.

---

Résumé La décomposition thermique du disulfite de sodium 1,3 one 2 propane (NaO₃S. CH₂.CO.CH₂.SO₃Na) s'effectue avec disruption moléculaire complète et obtention de résidus constitués de sulfate de sodium ou de mélanges de sulfate de sodium et de carbonate de sodium, tant en atmosphère d'oxygène que d'azote. Aucun composé organique n'est détecté dans les produits volatils.

---

--2--1,3- (NaO₃S. CH₂. CO. CH₂. SO₃Na) . .

     

Macromolecular conformations at the water-air interface: Interactions between alpha and beta conformations of polypeptides

Bidimensional miscibility between alpha and beta conformations of polypeptides was investigated at the water-air interface in the 15°–30°C temperature range. The polypeptides were poly--methyl-L-glutamate (PGMG), poly--benzyl-L-glutamate (PGBG) and poly--benzyl-L-aspartate (PBBA). The polypeptide conformations, alpha or beta, were checked by IR spectroscopy using the MIR technique.The spreading isotherms for mixed monolayers alpha-PGMG/alpha-PGBG and beta-PGMG/beta-PBBA showed bidimensional miscibility both for alpha-alpha and beta-beta mixtures.For the alpha-alpha system, attractive interactions among the polypeptide alphahelices were found (G_mix<0) and the driving factor appeared to be the entropic one (packing). Compressibility moduli and surface potential measurements showed a fluidification effect of alpha-PGBG on mixed monolayers. In the case of beta-beta mixed monolayers, ideal behaviour was observed and no fluidification effect detected.Scanning electron micrographs made on collapsed monolayers showed hexagonal structures for alpha-alpha mixtures and no well-defined or characterized features for the beta-beta system.     

Symmetry and other properties of second-order phenomenological coefficients and thier significance in a chemical system

Using a second-order phenomenological equationJ _i = _j L _ij X_j + _{j, k} L _ijk X_j X_kand assuming that the system is at a state near equilibrium, it has been shown that the symmetry ofL _ijk is retained with respect to the permutations of suffices i j and k Furthermore, using the second-order flux equations, the thermodynamic stability criterion is expressed. The symmetry is shown to be retained in a reaction scheme representing the emplate model. The significance of the stability criterion as expressed by the higher-order phenomenological coefficients is discussed.     

Kinetics of the gas-phase pyrolysis of some secondary acetates

The rates of the gas-phase thermal decomposition of three secondary acetates have been measured in a static system over the temperature range 290–350°C and pressure range 54–250 Torr. The reactions in seasoned vessels are homogeneous, follow a first order-law, and are unimolecular. The effect of -substituents in acetates is discussed.

---

290–350°C 54–250 . , , , . - .

     

Magnetische Messungen im System Fe—Te

In the binary Fe–Te system six intermediate solid phases exist with varying ranges of homogeneity. With the exception of the high temperature -phase the magnetic behavior of these phases and in some cases the variation of magnetic properties with composition were investigated by susceptibility measurements in the temperature range from 100 to 300 K. Both the -phase (FeTe_1–x ) and the -phase (Fe₅Te₆) follow theCurie—Weiss law and can be designated as antiferromagnetic compounds according to the negativeWeiss constants of –192 K and –314 K, resp. The magnetic moments identify these two phases as high-spin compounds of Fe. The observed increase of the magnetic moments towards the Ferich limit of the -phase is due to the occupation of the octahedral interstices in the anion sublattice by excess iron and it was explained by a simple model. The magnetic moment of the hypothetical equiatomic compounds FeTe, obtained by extrapolation (3.87 _B), as well as the moment of the -phase (3.83 _B) are nearly identical and can be interpreted as being due to the existence of three unpaired 3d-electrons per formula unit. For the Te-rich (Fe_1–x Te)-, (Fe_1–x Te)- and (FeTe₂)-phases the transition metal is supposed to be in the low-spin state. The observedPauli paramagnetism is not temperature independent but decreases with decreasing temperature. Below 100 K FeTe₂ appears to be diamagnetic.

---

---

Mit 7 Abbildungen     

Rotamerism and roulettamerism of vertex-sharing biicosahedral supraclusters: Synthesis and structure of [(Ph3P)10Au13Ag12Cl8](SbF6)

The relative rotation of two centered icosahedra of a vertex-sharing biicosahedral supracluster about the pentagonal symmetry axis gives rise to cluster rotamerism while the relative rotation of the satellite ring of six bridging halide ligands around the equator with respect to the metal framework gives rise to cluster roulettamerism; the latter is exemplified by the structures of [(Ph₃P)₁₀Au₁₃Ag₁₂ X ₈]⁺ X=Cl (this work) or Br.     

Formation mechanism and structure of compounds catalytically active in propylene dimerization and formed in Pd(acac)2?PR3?BF3OEt2 systems

The interaction between the components of catalytic Pd(acac)₂–PR₃–BF₃OEt₂ systems dimerizing propylene to linear hexenes with 59 % selectivity, has been studied by UV and¹H NMR spectroscopy methods. Formation mechanism of catalytically active [R₃P–Pd–H]⁺BF ₄ ^– compounds is suggested.

---

, ¹ Pd(acac)₂–PR₃–BF₃OEt₂, 59%, [R₃P–Pd–H]⁺BF ₄ ^– .

     

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.

---

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.

---

---

Die Wellenfunktionen können auf Anfrage zur Verfügung gestellt werden.     

Heterogeneous catalytic oxidation of ethanol: A new process for acetic acid

ESR investigations on ZnO doped with various amounts of -Al₂O₃ thermally treated, are reported. Experimental data are related to the electronic structure of ZnO--Al₂O₃ and to desulfurization specific activity for natural gas.

---

ZnO, -Al₂O₃. ZnO/-Al₂O₃ .

     

Study of solid-phase reaction between CsNO3 AND V2O5 in the molar ratio 6:5

Using DTA, DTG and TG methods, the solid-phase reaction between CsNO₃ and V₂O₅ in the molar ratio 65 has been studied in oxygen and air streams in the temperature range 20–550°. The reaction proceeds stepwise and CsV₃O₈ has been identified as an intermediate. A mixture of CsVO₃ and Cs₂V₄O₁₁ is formed as final product of the reaction at 520°. The composition of this mixture does not change up to 1000°.

---

Zusammenfassung Unter Anwendung der Methoden DTA, DTG und TG wurde die Festphasenreaktion von CsNO₃ und V₂O₃ im Molverhältnis von 65 im Sauerstoff- und Luftstrom im Temperaturbereich von 20 bis 550° untersucht. Die Reaktion verläuft stufenweise und CsV₃O₃ wurde als Zwischenprodukt identifiziert. Als Endprodukt der Reaktion bei 520° bildete sich ein Gemisch von CsVO₃ und Cs₃V₃O₁₁. Die Zusammensetzung dieses Gemisches ändert sich bis 1000° nicht.

---

Resumé On a étudié par ATD, TGD et TG, la réaction en phase solide entre CsNO₃ et V₂O₅ avec le rapport molaire de 65, dans un courant d'oxygène et d'air, dans l'intervalle de températures compris entre 20 et 550°. La réaction s'effectue par étapes et on a identifié CsV₃O₃ comme produit intermédiaire. Lors de la réaction à 520°, un mélange de CsVO₃ et Cs₂V₄O₃ se forme comme produit final. La composition de ce mélange ne varie pas jusqu'à 1000°.

---

, , CsNO₃ V₂O₅ 6 5 20–550°. CsV₃O₈. 520° CsVO₃ Cs₂V₄O₁₁, 1000°.

     

IR spectra of oxygen adsorbed on SnO2

IR spectra of oxygen adsorbed on SnO₂ with and without lattice defects have been studied. At low temperatures oxygen is adsorbed on defect SnO₂ in two forms of O ₂ ^– . This supports the earlier results obtained by ESR. The low-temperature forms of adsorbed oxygen (unrevealed in ESR spectra) were detected on defectless SnO₂. High-temperature forms of adsorbed oxygen appear in the IR-spectra as bands due to vibrations of the cation-oxygen bond.

---

- SnO₂. , O ₂ ^– , . SnO₂ .