Combination and disproportionation of methyl and 2-propyl radicals with 1,1,2-trimethylallyl radicals

The combinations and disproportionations of the CH₃ and 2-propyl (iP) radicals with the 1,1,2-trimethylallyl (TMA) radical have been studied in the gas phase in the temperature interval of 389–451 K and 490–540 K, respectively. For the ratios of the terminal (t) and non-terminal (n) combinations of the CH₃ and iP radicals with the TMA radical, values of 1.9±0.1 and 2.84±±0.10 were obtained, respectively. The ratios of the tt and tn and nn to tn combinations of the TMA radical were 1.59 and 0.46, respectively. The disproportionation-combination rations were (CH₃ , TMA)=0.022±±0.012 and (iP, TMA)=0.026±0.011.

---

CH ₃ 2- (iP) 1,1,2- (TMA) : 389–451 K 490–540 K. (t) (n) TMA 1,9±0,1 2,84±0,10, . tt tn nn tn TMA 1,59 0,46, . (CH ₃ , TMA)=0,022±0,012 (iP, TMA)=0,026±0,011.

     

Beckmann rearrangement of cyclohexanone oxime p-toluenesulfonate on acidic catalysts

The Beckmann rearrangement of cyclohexanone oxime p-toluenesulfonate has been studied using several catalysts. The reaction is catalyzed by weakly acidic sites and seems to occur by way of O-(p-toluenesulfonyl)--caprolactim.

---

- -, . - -(-)--.

     

Recombination mechanism of hydrogen atoms on ZnS surface

It has been established that physically adsorbed and chemisorbed atoms take part in the recombination of H-atoms on ZnS surface.

---

- ZnS .

     

Activity in CO oxidation of manganese dioxide for batteries

The low temperature oxidation of CO over MnO₂ containing samples for batteries has been investigated. It is found that the samples contain compositional and hydrate water and Mn⁴⁺, Mn³⁺, Mn²⁺ ions. The high efficiency is due to Mn⁴⁺ content.

---

CO MnO₂, . , Mn⁴⁺, Mn³⁺, Mn²⁺. Mn⁴⁺.

     

Synthesis and thermostability of the binary condensed phosphates

Some condensed phosphates, especially cyclo-tetraphosphates have been synthetized as new binary compounds and their existence has been proved. The synthesis of cyclo-CdMgP₄O₁₂ is shown as an example. The products crystallize in the monoclinic system (C2c group) and are stable to 900°C. The synthesis is based on a thermal procedure making use of the reversible transformation of cyclo-tetraphosphates to higher linear phosphates (the 1.method) and on a calcination of the starting binary dihydrogenphosphate at quasi-isothermal-isobaric conditions (the 2.method).

---

Zusammenfassung Einige kondensierte Phosphate, im besonderen Zyklotetraphosphate wurden als neue binäre Verbindungen hergestellt. Als Beispiel wird Zyklo-Cd MgP₄ O₁₂ angeführt. Das Produkt kristallisiert monoklin /Gruppe C2/c/ und ist bis 900°C stabil. Die Synthese basiert auf einem thermischen Verfahren unter Anwendung des reversiblen Überganges von Zyklotetraphosphaten zu höhereren linearen Phosphaten /Verfahren 1/ und auf dem Kalzinieren der binären Ausgangsverbindung Dihydrogenphos phat bei quasi-isothermen-isobaren Bedingungen /Verfahren 2/.

---

$ , . - dMgP₄O_I2. $ / 2/ $ 900°. $ $ , — $ - .

     

Toluene disproportionation and coke formation over fluorided alumina and hydrogen-mordenite

Toluene transformation was investigated on a fluorided alumina and a protonic mordenite under hydrogen (0.8, 12 bar) and under nitrogen (12 bar). Hydrogen pressure considerably improves the catalytic stability of H-mordenite by inhibiting the formation of coke. Moreover, hydrogen eliminates part of the coke deposited by reaction under nitrogen, and regenerates the activity of the mordenite. On the contrary, hydrogen has no effect in the case of fluorided alumina. The particular behavior of the mordenite is attributed to its very strong acidity.

---

(0,8, 12 ) (12 ). -, . , , , . , - . .

     

Electronic state of the active site of A V?P?O/SiO2 catalyst in oxidation of chlorine-containing hydrocarbons

V⁴⁺ ions in slightly associated states are supposed to play the role of V–P–O/SiO₂ active sites. V⁴⁺ ions are reduced to V³⁺ during deactivation of the V–P–O/SiO₂ catalyst.

---

V–P–O/SiO₂ V⁴⁺ . V–P–O/SiO₂ V⁴⁺ V³⁺.

     

Thermogravimetric determination of oxygen in transition metal oxides with a derivatograph

The thermal decompositions of a series of complex copper oxides and some other transition metal oxides were studied by simultaneous TG-DTA. The oxygen stoichiometry was determined by thermogravimetry. For the compound YBa₂Cu₃O_7–x, the electrical properties and some structural peculiarities depend on the oxygen content.

---

Zusammenfassung Die thermische Zersetzung einer Reihe von komplexen oxidischen Kupferverbindungen sowie weiterer Übergangsmetallverbindungen wurde durch simultane TG-DTA untersucht. Die Sauerstoff-Stöchiometrie dieser Verbindungen wurde durch Thermogravimetrie ermittelt. Bei der Verbindung YBa₂Cu₃O_7–x wurde eine Abhängigkeit der elektrischen Eigenschaften und einiger struktureller Besonderheiten vom Sauerstoffgehalt gefunden.

---

R . . , YBa₂Cu₃O_7–x .

     

DTA-controlled reactions and phase relations in the ternary system Sn-Te-I

The system Sn-Te-I was investigated by DTA and X-ray powder methods. No intermediate ternary phase exists in the respective phase diagram. Reactions of the components on pseudobinary joins are easily explained by the phase relations. Liquidus isotherms of the ternary system are given.

---

Zusammenfassung Das System Sn-Te-I wurde durch DTA- und Röntgenmethoden untersucht. In dem Phasendiagramm existiert keine intermediäre Ternärphase. Die Reaktionen der Komponenten der pseudobinären Koppelungen können durch die Phasenverhältnisse leicht erklärt werden. Flüssigkeitsisothermen des Ternärsystems werden gegeben.

---

Résumé Le système Sn-Te-I a été étudié pa ATD et rayons X sur poudre. Il n'existe pas de phase ternaire intermédiaire dans le diagramme de phases correspondant. Les réactions des composants en systèmes pseudobinaires s'expliquent facilement par les relations de phases. Les isothermes des liquidus du système ternaire sont données.

---

Sn--I. . . .

     

Décomposition thermique du sulfite de fer(II) anhydre

Résumé Sous azote ou sous vide, le sulfite ferreux anhydre se décompose vers 210° en magnétite, pyrite et dioxyde de soufre. Concurremment une réaction de dismutation intervient avec formation de FeSO₄, Fe₃O₄ et FeS₂. Lorsque la température atteint 320°, la pyrite et le sulfate réagissent ensemble pour donner Fe_1–xS, Fe₃O₄ et SO₂. Au-delà de 370° le sulfure ferreux non-stchiométrique commence à réagir à son tour avec le sulfate restant pour former de la magnetite et du dioxyde de soufre.

---

In nitrogen or under vacuum, anhydrous iron(II) sulfite decomposes near 210° to magnetite, pyrite and sulfur dioxide. A parallel disproportionation reaction occurs with formation of FeSO₄, Fe₃O₄ and FeS₂. When the temperature reaches 320°, pyrite and sulfate react together to give Fe_1–xS, Fe₃O₄ and SO₂. Above 370° the non-stoichiometric ferrous sulfide begins to react with the remaining sulfate to give magnetite and sulfur dioxide.

---

Zusammenfassung Unter Stickstoff oder im Vakuum zersetzt sich das wasserfreie Eisen(II)-sulfit in der Nähe von 210 °C zu Magnetit, Pyrit und Schwefeldioxid. Parallel hierzu findet eine Disproportionierung unter Bildung von FeSO₄, Fe₃O₄ und FeS₂ statt. Wenn die Temperatur 320 °C erreicht, reagieren Pyrit und Sulfat unter Bildung von Fe_1–xS, Fe₃O₄ und SO₂ Oberhalb von 370 °C beginnt das nichtstöchiometrische Eisensulfit seinerseits mit dem restlichen Sulfat zu reagieren um Magnetit und Schwefeldioxid zu ergeben.

---

(II) 210° , . FeSO₄, Fe₃O₄ FeS₂. 320°, , Fe_1–xS, Fe₃O₄ SO₂. 370° .

     

Kinetics of CO2 formation in thermal destruction of brown coals

The previously suggested approach to the problem of kinetic system identification /1/ was used for the system of independent first order reactions. The analysis of the curves of CO₂ formation in thermal destruction of brown coal indicates that both structure and model parameters of real processs can be identified in terms of the continuity concepts.

---

(I) ë . CO₂ , , .

     

Etude thermoanalytique de quelques steroides I — Monovalerianate d'estradiol et estriol

A thermoanalytical study of estradiol monovalerate (a) and estriol (b) revealed the thermal stability, the decomposition kinetics, and the temperatures and intervals of fusion. The degree of purity was calculated only for estradiol monovalerate: 99.72 ± 0.11 mol %. The fusion enthalpy (29.45±0.47 kJ mol^–1) and entropy for this compound were evaluated by differential scanning calorimetry. It was also possible to detect the polymorphism and the pseudopolymorphism of (a) and (b) after recrystallization from several solvents.

---

Zusammenfassung Die thermische Stabilität, die Zersetzungskinetik sowie die Schmeiztemperaturen und -intervalle von Estradiol-Monovalerianat (a) und Estriol (b) wurden thermoanalytisch ermittelt. Nur der Reinheitsgrad von (a) wurde berechnet (99,72 ± 0,11 mol %). Die Schmelzenthalpie (29,45±0,47 kJ · mol^–1) und Schmelzentropie dieser Verbindung wurden mittels DSC bestimmt. Nach Rekristallisation in verschiedenen Lösungsmitteln konnten Polymorphie und Pseudopolymorphie für (a) und (b) nachgewiesen werden.

---

, . 99,72±0,11 %. (29,45±0,47 · ^–1) . , .

     

Polyfunctional zeolite catalysts in the benzene-olefin-hydrogen system

Benzene alkylation by C₂–C₄ olefins in the presence of hydrogen over a steam-treated zeolite catalyst containing lanthanum and nickel, has been studied. The promoting action of hydrogen on benzene alkylation by propylene has been established.

---

C₂–C₄ , . .

     

Temperature-programmed desorption (TPD) of various bases from HY zeolites

The temperature programmed desorption of several bases from a HY zeolite has shown that the activation energy of desorption represents a useful measure for characterizing the acidic properties.

---

- HY , , .

     

Physico-chemical transformations during heating of phosphorites

The thermal behaviour of phosphorites in an oxygen or helium atmosphere was studied by means of simultaneous TG-DTG-DTA-gas titrimetric EGA. Thermal oxidation and/or decomposition steps of the contaminating organic materials, carbonate minerals and pyrite, and of the fluorocarbonate-apatite were identified. The evolution of CO₂ from the latter has its maximum at 750–850 °C and is accompanied by an increase in the lattice parametera ₀.

---

Zusammenfassung Das thermische Verhalten von Phosphoriten in Sauerstoff- oder Heliumatmosphäre wurde durch simultane TG-DTG-DTA-EGA (mittels Gastitrimetrie) untersucht. Thermische Oxidations- und/oder Zersetzungsschritte der Verunreinigungen (organische Materialien, Carbonatminerale und Pyrit) und des Calcium-fluoro-carbonat-apatit wurden identifziert. Die CO₂-Abspaltung aus dem letzteren hat ihr Maximum bei 750–850 °C, sie ist begleitet von einer Vergrösserung des Gitterparametersa ₀.

---

, , - . ( , , . 750–850° ₀.

     

Oxidative coupling of 5-membered heterocycles catalyzed by a Pd(II)-heteropolyacid system in dimethylformamide

Oxidative coupling of thiophene and 2-methylfuran to the corresponding dihetaryls in DMFA medium occurs in the presence of the homogeneous catalytic system Pd(II)-molybdovanodophosphoric heteropolyacid (HPA). The data obtained show that HPA may act as a reversible oxidant in polar aprotic media.

---

, Pd(II)- 2- . , .

     

Cyclohexanol conversion of Pt-and Co-promoted molybdena-alumina; Effect of S-uptake

The uptake of sulfur reduces the overall activity of PtMo/Al₂O₃ and enhances that of CoMo/Al₂O₃ in conversion of cyclohexanol. Significant changes in selectivity indicate the existence of different active sites of the initial catalyst for hydro-dehydrogenation and dehydration. The differences in catalytic activity expressed in terms of overall TOF decrease with increasing sulfur treatment like for Ru and Ir promoted catalysts.

---

PtMo/Al₂O₃ CoMo/Al₂O₃. - . Ru .

     

Kinetics and mechanism of oxidation of D-altrose by aqua-cerium(IV) in perchloric acid medium

Kinetics of the oxidation of D-altrose by Ce(IV) perchlorate has been studied in perchloric acid medium. At equivalent concentrations the overall order of the reaction is two, being unity in each reactant. The reaction is characterized by a primary positive kinetic salt effect. Perchloric acid has been found to enhance the rate, while the addition of the reaction products retards the rate. No evidence for initial complexation has been obtained. Thermodynamic parameters have been determined and a mechanism consistent with the observed results is proposed.

---

D- Ce(IV) . , . . , . . , .

     

Study of the combustion of a fire retardant coating by thermal analysis and different complementary techniques

An intumescent fire retardant coating can effectively control fire spread and damage. Its dual purpose is to confine the surface spread of flame to the boundaries of an already established fire, and to retard the penetration of heat and flame to and through the coated surface. Our composition expanded and provided an insulation layer between the flame source and the combustion substrate, and liberated a quantity of primarily non-flammable decomposition products which tended to extinguish the flame. The main ingredients of the coating were cellulose acetate butyrate and HMDI (Desmodur N) for Polyurethane, and Chlorowax-70 (chlorinated paraffins) as fire retardant component. This fire retardant coating was applied to wood panels, and tested in a 2-foot tunnel, its flame spread rating being measured. The effects of three parameters of interest were investigated: the type of wood used, the percentage of Chlorowax, and the coating thickness. It was found of interest to study the oxidation of the coating using different techniques, e.g. flash pyrolysis under oxygen and GC/MS for analysis of the decomposed products. Combustion studies of the coating were also conducted using DSC and thermogravimetry, either with the scanning mode or under isothermal conditions. Comparisons were made between the results obtained from pyrolysis and combustion.

---

Zusammenfassung Ein schwellender feuerhemmender Überzug kann Ausbreitung und Schäden von Feuer wirksam einschränken und wird zwei Zwecken gerecht: Verhinderung der Ausbreitung von ausgebrochenem Feuer und Schutz der überzogenen Oberfläche vor Hitze- und direkter Flammeneinwirkung. Die beschriebene Komposition quillt und bildet eine Isolationsschicht zwischen der Flammenquelle und dem brennbaren Material, liefert zugleich aber auch eine gewisse Menge von nichtbrennbaren, die Flamme erstickenden primären Zersetzungsprodukten. Die Hauptbestandteile des Überzugs sind Celluloseacetat und -butyrat und HMDI (Desmodur N) für Polyurethan sowie Chlorowax-70 (chlorierte Paraffine) als feuerhemmende Komponente. Dieser feuerhemmende Überzug wurde auf Holzplatten aufgebracht und in einem 2ft-Tunnel getestet, wobei die Flammenausbreitungsgeschwindigkeit gemessen wurde. Der Einfluß von drei interessierenden Parametern wurde untersucht: Typ des benutzten Holzes, Anteil von Chlorowax und Überzugsschichtdicke. Es erwies sich als interessant, die Oxydation des Überzugmaterials mit verschiedenen Techniken zu untersuchen, z.B. durch Schnellpyrolyse und Analyse der Zersetzungsprodukte mittels GC/MS. Verbrennungsuntersuchungen des Überzugmaterials wurden auch mittels DSC und Thermogravimetrie entweder nach der scanning-Arbeitsweise oder unter isothermen Bedingungen ausgeführt. Die bei Pyrolyse und Verbrennung erhaltenen Ergebnisse werden miteinander verglichen.

---

. -, , — . , . - ( ) ( ) . , . : , . , , , - . . , .