Simple statistical mechanics of electrolytes with a concentration dependent dielectric constant. Part 1. The pressure equation

We have used an approximation of the Adelman's theory of solutions to take into account the non-pairwise additive effects on the interaction potentials for a real electrolyte solution. As a result, a solute concentration dependent dielectric constant appears. The comparison with experimental data is done by means of the pressure equation. The influence of on solution properties is analyzed in two molality ranges using as a reference simplified models but with the dielectric constant of the pure solvent instead of .     

Effect of the Allyl Group in Reactions of Allyl Alcohol and Its Derivatives with ε-Caprolactam

Unlike saturated alcohols, allyl alcohol reacts with -caprolactam under considerably milder conditions. Allyl esters react with -caprolactam to give the corresponding allyl -acylaminocaproates. The yield of the latter decreases in going from formyl to acetyl and propionyl derivatives. The observed effect of the allyl group is explained in terms of possible allylic rearrangement in the transition state.     

On the asymptotic behavior of Hartree-Fock orbitals

Summary Handy et al. have shown that the asymptotic behavior of Hartree-Fock orbitals is controlled by the energy of highest occupied molecular orbital, except for the atomic case in which onlys-orbitals are occupied. However, their proof is not complete at one point. This point is clarified, and a more unified derivation is given. Further, we discuss the preexponential factorr of the leading asymptotic termr exp[–r], where =(–2_HOMO)^1/2 and _HOMO is the orbital energy of HOMO. New results are obtained for linear molecules, and the results of several authors for atoms and non-linear molecules are reproduced.     

Dielectric properties of mixtures of acetylene tetrachloride with toluene and acetone

Relative permittivities are reported for binary liquid mixtures of acetylene tetrachloride (ATC) with toluene and acetone at 35°C. Measurements of refractive indices have also been made for the mixtures. The values of the quantity , the deviations of the relative permittivities of these mixtures from ideality, have been calculated. The negative values of obtained for ATC+ toluene mixtures may be explained as being due to a decrease in the degree of alignment of the molecular dipoles with changing composition of the mixture, whereas the positive values of obtained for ATC+acetone mixtures are attributed to the formation of molecular complex between acetone and CHCl₂CHCl₂. The values of the Kirkwood correlation parameter g for both sets of mixtures have been calculated using the relative permittivity data.     

Numerisch einfache Bezichungen zwischen Verlust- und Speicherkomponente des dynamischen dielektrischen Faktors

Zusammenfassung Es werden Formeln hergeleitet, die wie die Kramers-Kronig-Beziehungen Verlust- und Speicherkomponente des dynamischen komplexen dielektrischen Faktors*() miteinander in Verbindung bringen, die aber den Vorteil haben, daß kein Integral mehr auftritt und daß sich der Einfluß der jeweiligen Kurvenausläufer für bzw. 0 in Form einer einfach gebauten Summe aus Stützstellenwerten darstellen läßt. Die Stützstellen steigen mit dem Faktor 2 an, bzw. fallen mit dem Faktor 1/2 ab.So lassen sich die Glieder mit experimentell nicht zugänglichen Meßwerten eliminieren und lineare Näherungsgleichungen zwischen wenigen Stützstellenwerten der einen und der anderen Komponente finden. Die Genauigkeit dieser Näherungen läßt sich relativ zur Verlustkomponente. angeben. Die Beziehungen sind sehr gut geeignet, Meßungenauigkeiten aufzuzeigen und durch Nachkorrektur auszugleichen.Außerdem werden zwei Beziehungen gefunden, mit deren Hilfe die logarithmische Ableitung der Speicherkomponente aus wenigen Stützstellenwerten von. und einfach berechnet werden kann. Diese negative logarithmische Ableitung von scheint noch besser geeignet als., Dispersionsstufen durch Maxima anzuzeigen. Schließlich wird eine Formel aufgestellt, mit der aus dynamischen Messungen eine obere Grenze für die statische Leitfähigkeit ausgerechnet werden kann.

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Summary Formulas are derived, which relate the loss component. to the storage component of the dielectric permittivity* as the Kramers-Kronig equations do. The advantage of the formulas given is, that they involve simple sums of functional values instead of integrals. The influence of unaccessible parts of either. or, when is too large or too small for measurements, can be estimated easier. By combining the equations at different values of it is possible to eliminate the functional values at very large and at very small values of. Thus relations are obtained, which are very useful for checking measurements as is shown by application for an example of experimental data.Additional relations are given, which allow to calculate the logarithmic derivative of from a few values of and. The negative logarithmic derivative of seems to indicate transitions of materials more clearly than does. Finally a formula is derived, which allows to calculate an upper limit of the static conductivity from dynamic measurements.

     

Validity of energy distribution derived from heat of adsorption in an ammonia/cation-exchanged Y zeolite system

The validity of- functions (energy level functions) which were derived from experimentalq- functions (heat functions) was examined in an ammonia/cation-exchanged Y zeolite system. The- functions of Na-Y zeolite and Cs-Na-Y zeolite were respectively calculated from theirq- functions measured by ammonia adsorption at 373 K. The heat of adsorption of ammonia was also measured on a mixture of these two zeolites at a certain mixing ratio at 373 K. The- function of the mixture was likewise calculated on the basis of this measurement. The- function thus calculated was in good agreement with the synthesized- function derived by linearly combining two- functions of each zeolite mentioned above. The- function derived from experimental- function thus proved to be valid in an actual adsorption system.     

Estimation of heat of adsorption from energy distribution on heterogeneous surfaces by a theoretical analysis of adsorption process

An attempt was made to calculate theq— function (experimental heat function) from the— function (energy level function) of a heterogeneous surface. In order to obtain the heat of adsorption, adsorption was assumed to take place on each energy level of the— function. In reversible adsorption, Langmuir's monolayer model was extended to determine the occupation of energy levels by molecules. On this basis, the heat of adsorption could be calculated. Irreversible adsorption was also examined on the basis of chemical kinetics. Molecules were supposed to be held on sites to which they first collided. These calculations were useful for estimating the extent of deviation of theq— function from the— function.     

Dielectric properties of moist CaCO3 filled polyethylene composites

The capacitance and the dielectric loss tangents of CaCO₃ filled polyethylene composites were studied. Composite samples, prepared by polymerizing ethylene on the surfaces of fillers, pre-treated by polymerization catalysts, were compared to normal mechanical mixtures. Dielectric dispersion,, and loss, , proved to be sensitive to heating or vacuum treatment. Investigation of samples under conditions of different relative humidities showed that the dielectric dispersion is due to adsorbed water. Both and increased with decreasing frequency and the ratio of loss and dispersion was nearly constant. Dielectric data measured at different relative humidities could be represented by a single Cole-Cole plot. Samples soaked in water for different periods yielded qualitatively similar but quantitatively different Cole-Cole plots. Composite samples showed higher losses at similar humidities.Possible interpretations in terms of a molecular relaxation model, an interfacial relaxation model, including a charged double layer mechanism, percolation theory and the universal response theory were examined, but none was able to fully explain the observed phenomena.     

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     

Complex polarizability as used to analyze dielectric relaxation measurements

The effect of representing dielectric properties in terms of the complex polarizability ^c = – i is examined. Loss curves ( and tan ) are shifted towards higher frequencies, revealing the existence of new relaxations and allowing the clarifications of ones already known. We have calculated the shift ratios (at maximum or tan )/ (at maximum or tan ) from the more conventional empirical equations representing the dielectric behavior. Some examples are given.     

Dielectric monitoring of biological cell sedimentation

A dielectric theory was developed to analyze dielectric relaxation of a system in which biological cells are settling perpendicular and parallel to electrode planes. The theory predicts that the dielectric relaxation intensity () increases markedly with increasing time when the settling direction is perpendicular to electrode planes, whereas is less sensitive to the sedimentation in a direction parallel to electrode planes. These theoretical expectations agreed well with the experimental results obtained with sheep erythrocytes. Analysis based on this theory provided the sedimentation rate of sheep erythrocytes, the results being in agreement with those obtained by the conventional method.     

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.

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V₂O₅/SiO₂ N₂O. .

     

Influence of the various forms of molybdena on the adsorptive and catalytic (dehydrogenation and hydrogenolysis) properties of molybdena-alumina catalysts

The contents of three forms of molybdenum oxide compounds in molybdena-alumina catalysts have been determined by their solubility in water and ammonia. The form which is readily soluble in water and reducible to Mo(IV) at 400°C and P_H2=10⁵ Pa is active in cyclohexane dehydration, and the forms soluble in water and ammonia are active in thiophene hydrogenolysis.

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. , 400°C P_{H 2}=I Mo(IV); — .

     

Kinetic and mechanistic studies on the oxidation of sulfanilic acid by peroxomonophosphoric acid

Oxidation of sulfanilic acid to the corresponding azoxy derivative by peroxomonophosphoric acid (PMPA) has been studied in aqueous medium. The observed bell-shaped pH-rate profile has been rationalized on the basis of protonation of the amino group and ionization into different PMPA species and a suitable rate law has been proposed. The mechanism of oxidation involves the nucleophilic attack of nitrogen on the electrophilic peroxo oxygen.

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- (PMPA) . pH— , PMPA . .

     

On the possibility of formation of Ti?Mo heteropolyacids on Ti?Mo catalysts

According to IR spectroscopic studies, a Ti–Mo heteropolyacid is formed on the surface of Ti–Mo catalysts prepared from ammonium paramolybdate and TiO₂.

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- , Ti–Mo TiO₂ Ti–Mo .

     

Quinazolines X. Synthesis of 6,6'-methylenebisdeoxyvasicinone and its homologs

Summary 6,6-Methylenebisdeoxyvacisinone and its homologs have been synthesized by the reaction of methylenebisanthranilic acid with lactams (-butyrolactam, -valerolactam, -caprolactam, and -chloro- and ,-dichloro--caprolactams). The condensation of anthranilic acid and its derivatives (4-nitro-, 5-bromo-, 5-iodo-, and 5-nitroanthranilic acids) with ,-dichloro--caprolactam has given seven-membered analogs of deoxyvasicinone containing two chlorine atoms in the polymethylene ring.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 544–547, July–August, 1977.     

Comparative study of single-crystal dehydration of LiCOOH.H2O and Li2SO4·H2O

The kinetics of isothermal dehydration of two crystal hydrates with equivalent water molecule sublattices (LiCOOH.H₂O and LiSO₄.H₂O) was investigated in vacuum with a quartz crystal microbalance, and the dynamics of structural reorganization of the substances was studied by the synchrotron radiation method. Differences were found both in the nucleation stage and in the stage of reaction interface advance. The results indicate that the kinetic behaviour of isothermal decomposition of solids is determined by the structural reorganization of a metastable intermediate.

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Zusammenfassung Die Kinetik der isothermen Entwässerung zweier Kristallhydrate mit gleichartigen Teilgittern der Wassermoleküle wurde untersucht mittels isothermer TG im Vakuum und Synchrotron-Röntgenbeugung. Unterschiede zwischen beiden Materialien werden sowohl in der Keimbildungswie- wei in der Ausbreitungsphase gefunden. Die Ergebnisse zeigen, dass die Kinetik der isothermen Zersetzung fester Stoffe durch die strukturelle Reorganisation eines metastabilen Zwischenprodukts bestimmt wird.

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HCOOLi.H₂O Li₂SO₄.H₂O . , — . , . , .

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The authors would like to thank N. Kosova for experimental assistance.     

Hydrogen formation in silane oxidation

From mass-spectrometric data, it has been established that the main gaseous product of silane oxidation by oxygen at low pressures is molecular hydrogen. Isotopic analysis of the hydrogen formed in the oxidation of SiH₄+SiD₄ mixtures indicates that not less than 20% hydrogen is generated by a molecular mechanism.

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- , . , SiH₄+SiD₄ , 20% .

     

TG and EGA investigations of the decomposition of magnesium ammonium phosphate hexahydrate by means of the Derivatograph under conventional and quasiisothermal — Quasi-isobaric conditions

An investigation was made of the thermal decomposition of MgNH₄PO₄ · 6H₂O under conventional and under quasi-isothermal—quasi-isobaric conditions. The experiments were carried out with a Derivatograph-suitable for simultaneous TG and EGA examinations. It was found that the thermal decomposition of MgNH₄PO₄·6H₂O consists of three, more or less overlapping partial processes. First 5 moles, then 1 mole of water of crystallization depart, and finally, strictly simultaneously and in an inseparable way, the departure of the ammonia and water of constitution takes place. The three processes can be separated best under quasi-isothermal and quasi-isobaric conditions.

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Zusammenfassung Die Autoren untersuchten die thermische Zersetzung von MgNH₄PO₄·6H₂O unter konventionellen und quasi isothermischen — quasi isobaren Bedingungen. Die Versuche wurden mit einem zur TG- und EGA-Analyse geeigneten Derivatograph-Typ durchgeführt. Die Autoren fanden, daß die thermische Zersetzung von MgNH₄PO₄·6H₂O aus drei mehr oder weniger überlappenden Teilvorgängen besteht. Zuerst werden 5, dann 1 Mol Kristallwasser entfernt, das Konstitutionswasser und Ammoniak werden streng simultan und von einander untrennbar entfernt. Die drei Vorgänge können am besten unter quasi isothermischen und quasi isobaren Bedingungen von einander getrennt werden.

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Résumé Les auteurs ont étudié la décomposition thermique de MgNH₄PO₄·6H₂O dans les conditions conventionelles ainsi que dans des conditions presque isothermes et presque isobares. On a effectué les expériences à l'aide d'un Derivatograph qui se prête aux études simultanées par TG et AGE. Dans les conditions conventionnelles, la décomposition thermique de MgNH₄PO₄·6H₂O s'effectue en trois processus élémentaires qui se recouvrent plus ou moins. Le départ de 5 puis d'une molécule d'eau de cristallisation est suivi de celui d'ammoniac et d'eau de constitution, celui-ci étant strictement simultané et indissociable. Ces trois processus peuvent être mieux séparés si l'on opère dans des conditions voisines du régime isotherme et isobare.

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MgNH₄PO₄·6₂ - - . , TG GA . , MgNH₄PO₄·6₂ . , , . - - .

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The authors wish to thank Prof. E. Pungor for valuable discussions and Mr. M. Arnold for his assistance in performing the experiments.