Untersuchung der thermischen Eigenschaften von Alkalibenzolsulfonaten

Zusammenfassung Der Einfluß von Atmosphäre, Aufheizungsgeschwindigkeit und Spülgasgeschwindigkeit auf die thermische Zersetzung von Alkalibenzolsulfonaten wurde untersucht. Kristallwassergehalt, Dehydratations-temperatur und -wärme, gegebenenfalls die Zusammensetzung, Art, Temperatur und Wärme der Modifikationsänderungen, Schmelzpunkte und Schmelzwärmen der Verbindungen wurden bestimmt. Die Zersetzung verläuft in zwei Abschnitten. In dem ersten Hauptteil entstehen in Inertgasatmosphäre Diphenyloxid, Diphenyl, Diphenylsulfon, Benzol, Phenol, Thiophenol, Diphenylsulfid, Thiantren, Diphenylenoxid und wahrscheinlich Diphenylensulfid, weiterhin Koks, Schwefeldioxid, Natriumsulfit und wenig Natriumsulfat, Natriumsulfid, Acetylen und Wasser. Im zweiten Hauptzersetzungsvorgang entstehen Natriumsulfid und Kohlenoxid. Die Produkte wurden isoliert und analysiert. Dazu wurden Derivatographie, Differentialthermoanalyse, Gaschromatographie, Infrarotspektroskopie, kontinuierliche thermische Titration und chemische Methoden gemeinsam angewandt.

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Summary An investigation was made of the influence of the atmosphere, rate of temperature rise, and velocity of the purging gas on the thermal decomposition of alkali benzene sulfonates. The crystal water content, the dehydration temperature and heat, and if need be the composition, the kind, temperature, and heat of the modification changes, melting points and heats of fusion of the compounds, were determined. The decomposition proceeds in two stages. In the first main stage (in an inert atmosphere) the resulting compounds include diphenyl oxide, diphenyl, diphenylsulfone, benzene, phenol, thiophenol, diphenyl sulfide, thianthrene, diphenylene oxide and probably diphenylene sulfide; also coke, sulfur dioxide, sodium sulfite and a little sodium sulfate, sodium sulfide, acetylene, water. Sodium sulfide and carbon monoxide are formed in the second main decomposition. The products were isolated and analyzed. Furthermore, use was made of derivatography, differential thermal analysis, gas chromatography, infra red spectroscopy, continuous thermal titration, and chemical methods.

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Résumé On a étudié l'influence de l'atmosphère, de la vitesse d'échauffement et de balayage du gaz, sur la décomposition thermique des benzène-sulfonates alcalins. On a déterminé la teneur en eau de cristallisation, la température et la chaleur de déshydratation, éventuellement la composition, la nature, la température et la chaleur des changements d'état, les points de fusion et les chaleurs de fusion des composés. La décomposition s'effectue en deux temps. Tout d'abord, en atmosphère inerte, il se forme de l'oxyde de diphényle, du diphényle, de la diphénylsulfone, du benzène, du phénol, du thiophénol, du sulfure de diphényle, du thianthrène, de l'oxyde de diphénylène et probablement du sulfure de diphénylène, et aussi du coke, de l'anhydride sulfureux, du sulfite de sodium et, en moins grande quantité, du sulfate de sodium, du sulfure de sodium, de l'acétylène et de l'eau. Dans une deuxième étape de la décomposition principale, du sulfure de sodium et de l'oxyde de carbone prennent naissance. On a isolé et analysé ces produits. Pour cela, on a utilisé simultanément la dérivatographie, l'analyse thermique différentielle, la chromatographie en phase gazeuse, la spectroscopie infrarouge, le titrage thermique en continu et les méthodes chimiques.

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Vorgetragen beim Symposium für analytische Chemie in Graz, 29. September bis 1. Oktober 1965.     

1,4 Addition to a perfluorinated cross-conjugated triene

Conclusions Perfluoro-(2-isobutenyl-1,1,4,4-tetramethyl-1,3-butadiene) yields 1,4 addition products both in nucleophilic addition and in radical chlorination.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1061–1064, May, 1979.     

Thermal degradation of copolymers of styrene and methyl-vinyl-silane by pyrolysis gas chromatography

Pyrolysis gas chromatographic investigations have been carried out on copolymers of styrene with trimethyl-vinyl-silane and of styrene with dimethyl-phenyl-vinyl-silane, in order to study the mechansims of thermal degradation and the copolymer structures. We have identified the pyrolysis products and measured their relative amounts. The experiments show that the controlling factor in the mechanism of the degradation is the nature of the side-group attached to the carbon atom at which chain scission occurs. If this side-group is phenyl, the main degradation process is depropagation; if it is if it is trimethyl-silyl or dimethyl-phenyl-silyl, intramolecular hydrogen abstraction followed by β scission becomes more important than depropagation. From the point of view of degradation mechanism, the nature of the side-group attached to the carbon atom from which the hydrogen is abstracted is of minor importance.We estimated the average copolymer block length from the amounts of products containing both comonomers as well as from the amounts of trimer composed of the same monomer.     

Discussion on the method for the measurement of the flexural modulus of coupled materials and reasons of the shifts of theQ −1 maxima caused by coupling

Summary When measuringQ ^–1 and the flexural resonance frequency of bars clamped at one end, constituted by a viscoelastic polymeric material glued to a rigid support of modulusE ₁, it is possible to calculate the componentsE ₂ andE ₂ of the complex elastic modulus of the polymeric material examined. In this work the minimum (critical) value of the ratioa=E ₂ /E ₁=a _c and the values of the ratioQ ₂ ^–1/Q ^–1=F ₁ are evaluated beyond which no exact calculation ofE ₂ and ofQ ₂ ^–1 is possible.Within the confidence limits of the linear viscoelasticity theory, these values depend on the accuracy of measurement of both frequency and resonance curve, as well as on the instrument employed, on the operating temperature and on the ratio between the thicknesses of the two coupled materials.In order to keep outside the critical conditions, the most convenient method involves the use of measurements of coupled test-pieces having different ratiosz between their thicknesses and of supports having different modulusE ₁, depending on the field of temperature of the analysis ofE ₂ and tg ₂ concerning and E.P.R. elastomer and a vulcanized cis-1,4 polyisoprene in very wide ranges of temperature comprising the glass transition. Moreover, it is demonstrated by analysis the shift on the temperature axis of the tg maximum of the composite test-piece with respect to the position of the tg maximum of the polymeric material alone.With 11 figures and 1 table     

Catalytic effect of nickel cyanide complex and skeletal nickel on addition of hydrogen to 6-methyl-3,5-heptadien-2-ol

Russian Chemical Bulletin -     

Thermodynamic excess quantities in the adsorption of sodium alkylsulfonates at the air-solution interface

Colloid and Polymer Science - Data on the surface tension of sodium alkylsulfonate solutions at different temperatures and surfactant concentrations are presented. By applying the thermodynamic...     

Two-photon absorption and energy band structure of orthorhombic Hg2Cl2 crystals

Dependence of two-photon absorption (TPA) rate on the state of polarization of a laser beam is investigated in the low-temperature orthorhombic modification of Hg₂Cl₂ crystals. Theoretical calculations of the dependence of TPA rate on the direction of polarization vector of the beam are performed for centrosymmetric points, Y, Z, T, R andS of the Brillouin zone. The domain structure of real crystals is taken into consideration and it is shown that periodicity of the polarization dependence may indicate whether TPA is due to transitions either at, Y, Z, T orR, S points. The polarization dependence of TPA cannot, however, distinguish between points inside these two groups. Comparison of theory with a low-temperature (T 8·5 K) experimental curve of polarization dependence is discussed. It is shown that the experiment can be explained in main features by a model of noninteracting oriented linear dipoles. Further, on the basis of TPA measurements, a simple energy band structure of Hg₂Cl₂ is proposed regarding Hg₂Cl₂ crystal as a linear chain of molecules.The authors express thanks to Dr. . Barta for supplying the Hg₂Cl₂ crystals, Dr. Z. Bryknar for critical comments and Dr. B. Velický for stimulating discussion. We thank also Dr. V. Kohlová for assistance during measurement.     

A model of processes determining the intensity of DAPS and AEAPS signals

A simple model including different processes important for the creation of APS signals formed by electrons is proposed. Mean probabilities of elastic and inelastic interactions of electrons with individual atom layers in the solid are introduced. The contribution of different layers to the DAPS and AEPS signals and the dependence of these signals on the interaction parameters are calculated.I am indebted to dr. J. Pavluch for valuable discussions.