Investigations of 2,3′-biquinolyl. 9. Reaction of 1′,4′-dihydro-2,3′-biquinolyl with organolithium compounds

The 1,4-dihydro-2,3-biquinolyl reacts with organolithium compounds to form the mixture of 4-R-1,4-dihydro-2,3-biquinolyls and 2-R-1,2-dihydro-2,3-biquinolyls in the ratio analogous to the conversion in the series of 2,3-biquinolyl. The utilization of the complex, the organolithium compound-TMEDA, in this process leads, after treatment of the reaction mixture with water, exclusively to 2-R-1,2-dihydro-2,3-biquinolyls. Treatment with methyl iodide leads to 1-methyl-2-R-1,2-dihydro-2,3-biquinolyls.     

Thermal investigation of the phase composition of poly(ethylene terephthalate). Analysis of different methods of determination of the degree of crystallinity of partially crystalline substances

The literature data on the degree of crystallinity of non-deformed poly(ethylene terephthalate) measured at various temperatures have been subjected to comparative analysis. There is no correlation between the results obtained by the different methods. The reason for this is shown to be the imperfections in the methods of determining the degree of crystallinity, which do not provide the true composition of the crystalline phase. Consideration has been paid to the validity of the main principles involved in the thermal method of determining the degree of crystallinity, so as to eliminate the imperfections in the existing methods and to provide the correct value of the mass of the crystalline phase. The phase composition of PET has been analyzed by the thermal method at different temperatures and conditions of crystallization. A marked difference from the literature data is observed in the range of low temperatures.

---

Zusammenfassung Eine vergleichende Analyse der Literaturangaben bezüglich des bei verschiedenen Temperaturen gemessenen Kristallisationsgrades von nicht-deformiertem Poly(äthylen-terephthalat) wurde durchgeführt. Zwischen den mit verschiedenen Methoden erhaltenen Ergebnissen besteht keine Korrelation. Es wurde gezeigt, daß der Grund hierfür in der Unvollkommenheit der Methoden zur Bestimmung des Kristallisationsgrades liegt, da diese nicht die wahre Zusammensetzung der Kristallinen Phase angeben. Die Gültigkeit der wichtigsten Prinzipien, welche die thermische Bestimmung des Kristallisationsgrades unter Ausschaltung der Unvollkommenheit der bestehenden Methoden gewährleisten und den richtigen Wert der Masse der kristallinen Phase angeben, wurden in Erwägung gezogen. Die Analyse der Phasenzusammensetzung von PET wurde durch die thermische Methode bei verschiedenen Temperaturen und Kristallisationsbedingungen durchgeführt. Ein deutlicher Unterschied zu den Literaturangaben kann im Bereich der niedrigen Temperaturen beobachtet werden.

---

. , , . , , . , , . . .

     

Catalytic properties and phase composition of multicomponent catalysts for oxidative ammonolysis of propane

Studies of the phase composition and catalytic properties of several complex oxide catalysts for oxidative ammonolysis of propane indicate that the active phases of these catalysts are antimonates of the respective metals. Phosphorus and tungsten additives to the catalysts promote the formation of such phase compositions, i.e. the formation of antimonates and the binding of excess antimony oxide.

---

. , ; , .

     

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.     

Nitration,amination, and halogenation of Di-O-methylphloracetophenone

Chlorination of the title compound gave 5- and 3-chloro-2-hydroxy-4,6-dimethoxyacetophenone. The nitration of its acetate, followed successively by reduction, diazotization, and reaction with cuprous chloride, gave the 3-substituted series, 2-acetoxy-4,6-dimethoxy-3-nitroacetophenone, 3-amino-2-hydroxy-4,6-dimethoxyacetophenone, and 3-chloro-2-hydroxy-4,6-methoxyacetophenone, respectively. The orientation of substituents in the products was proved. The amino and chloro members of the isomeric 5-substituted series were availablevia 2-hydroxy-4,6-dimethoxy-5-phenylazoacetophenone, the product of the reaction of the title compound with benzenediazonium chloride.

---

Nitrierung, Aminierung und Halogenierung von Di-O-methylphloracetophenon

Zusammenfassung Chlorierung der Titelverbindung gab 5- und 3-Chlor-2-hydroxy-4,6-dimethoxyacetophenon. Die Nitrierung des Acetats, gefolgt von Reduktion, Diazotierung und Reaktion mit CuCl ergab die 3-substituierte Reihe: 2-Acetoxy-4,6-dimethoxy-3-nitroacetophenon, 3-Amino-2-hydroxy-4,6-dimethoxyacetophenon und 3-Chlor-2-hydroxy-4,6-dimethoxyacetophenon. Die Orientierung der Substituenten wird diskutiert. Die Amino- und Chlorderivate der isomeren 5-substituierten Reihe sind über 2-Hydroxy-4,6-dimethoxy-5-phenylacetophenon zugängig, dem Produkt der Reaktion der Titelverbindung mit Phenyldiazoniumchlorid.

     

Vapor phase oxidation of methylpyridines on zeolite catalysts

It has been established that zeolites containing Pd and Cu ions catalyze the vapor phase oxidation of methylpyridines. In oxidation of 2-methylpyridine on PdCuNa-mordenite at 375 °C the yield of 2-pyridinecarbaldehyde is 40 % of its theoretical values.

---

, , Pd Cu, . 2- PdCuNa- 2- 375°C 40% .

     

Thermogravimetric changes influenced by the compaction of graphite-CrO3 intercalation compounds

The changes resulting from the compression of graphite-CrO₃ intercalation compounds are demonstrated in the TG curves. In comparison with the samples examined in the form of a flake bed, the compacted compounds begin to decompose at lower temperatures and their weight loss is higher, particularly above 220 °C. To explain the obtained results, the pressure-induced changes in the structures and the activities of the compounds are considered in relation to the method of intercalation, the concentration of the intercalant and the extent of exfoliation.

---

Zusammenfassung Anhand von TG-Kurven wurden Veränderungen demonstriert, die durch das Verdichten von Graphit-CrO₃-Einlagerungsverbindungen hervorgerufen werden. Im Vergleich zu Proben, untersucht in Form von Flocken, beginnen die kompakten Verbindungen sich bei niedrigeren Temperaturen zu zersetzen und zeigen einen grösseren Masseverlust, insbesondere beim Überschreiten von 220 °C. Zur Deutung der erhaltenen Ergebnisse wurden die druckverursachten Veränderungen in Hinsicht auf das Verfahren der Einlagerung, die Einlagerungskonzentration und auf das Ausmass der Abbröckelung in Betracht gezogen.

---

, -r₃. , , , 220°. , , .

     

Mechanism of silane oxidation

The polymerization of acrylonitrile has been studied in dimethylformamide in the presence of the complex catalyst tris-(-allyl/chromium and pyridine. The structure of the active sites of polymerization is discussed on the basis of experimental data.

---

, , - .

     

Determination of basic sites on the surface of metal oxide catalysts by desorption of benzoic acid

A method has been developed for the determination of the concentration of basic sites on white and deeply colored solid porous materials, which is based on the displacement of adsorbed benzoic acid by acetic acid. The determination is rapid and gives results comparable with those obrained by the titration with benzoic acid using thymolphthalein as indicator.

---

. . , , , .

     

Determination of the acidity of catalysts by thermoadsorption with a cyclic temperature program

A novel method is described, consisting in the determination of admolecules which are the most loosely bonded on the surface. This permits a better characterization of active centers on catalysts.

---

, , , , .

     

Reactivity of aromatic nitrons with alkyl and alkylperoxyl radicals

The catalytic properties of Mn(II)-histidine complexes for the oxidation of indigo carmine by H₂O₂ have been studied. It has been shown that the complex Mn(II) (Histidine)₂ existing in as a dimer is the true catalyst but at high concentration of the reactant the reaction is inhibited because of complex formation between the reactant and the catalyst.

---

Mn(II)- . , Mn(II)·()₂ . , .

     

Triterpene glycosides ofAstragalus and their genins XLV. The chemical transformation of cycloartanes 1. Synthesis of 25-norglycosides

Literature information is given on the current state of the study of the chemical transformation of cycloartane triterpenoids. A method has been developed for the transformation of the genin part of glycosides of 20,24-epoxycycloartan-25-ols with retention of the carbohydrate constituents. Three 25-norglycosides have been synthesized from natural cyclosieversigenin glycosides, namely 16-acetoxy-3,6-dihydroxy-20R,25-norcycloartan-20,24-olide 3-O-[O--L-arabinopyranosyl-(12)--D-xylopyranoside] 6-O--D-xylopyranoside (VIII), sodium 3,6,16,20-tetrahydroxy-20R,25-norcycloartan-24-oate 6-O--D-glucopyranoside 3-O--D-xylopyranoside (XII), and 20R,25-norcycloartane-3,6,16,20,24-pentaol 6-O--D-glucopyranoside 3-O--D-xylopyranoside (XIII).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 710–718, September–October, 1993.     

Kinetic study of the thermal decomposition of heterocyclic thiol complexes under non-isothermal conditions

The thermal decomposition in the solid-phase has been studied by thermogravimetric (TG) and differential thermal analysis (DTA) techniques for a number of heterocyclic thiol complexes. The method of Coats and Redfern was used to study the kinetics of the thermal decomposition process. The enthalpy changes and activation energies for the decomposition have been calculated.

---

Zusammenfassung Die thermische Zersetzung in fester Phase wurde an einigen heterozyklischen Thiolkomplexen mit den Methoden der dynamischen Thermogravimetrie (TG) und der Differentialthermoanalyse (DTA) untersucht. Die Methode von Coats und Redfern wurde zum Studium der Kinetik des thermischen Zersetzungsvorganges eingesetzt. Die Enthalpie-Änderungen und Aktivierungsenergien der Zersetzung wurden berechnet.

---

Résumé Etude de la décomposition thermique en phase solide de plusieurs complexes thiols hétérocycliques par thermogravimétrie (TG) et par analyse thermique différentielle (ATD). La méthode de Coats et Redfern a été appliquée pour déterminer la cinétique du processus de la décomposition thermique. Les variations d'enthalpie et les énergies d'activation de la décomposition ont été calculées.

---

(TG) (DTA) . . .

---

---

We are grateful to Prof. K. C. Joshi, Head of the Chemistry Department and Dr. A. K. Rai of Rajasthan University, Jaipur for permitting the generous use of the thermorecording balance at the University and to Dr. E. R. Saxena, Assistant Director, Mineral Products and Inorganic Chemicals Division and Mr. P. Narayanachar of Regional Research Laboratory, Hyderabad for their valuable assistance in taking DTA trace. Thanks are also due to Prof. V. V. S. Murti, Head of the Chemistry Department, University of Delhi for his interest in the work. The author (K. A. V.) thanks the University Grants Commission, New Delhi for the award of the fellowship under which these investigations have been carried out.     

George Martine,M.D., F.R.S. (1700–1741) an early thermal analyst?

A study of the life and work of George Martine, who seems to have been the first to have used the principle of differential thermal analysis, reveals that his stature scientifically (and perhaps medically) has not as yet been fully appreciated. A complete bibliography of his writings is appended.

---

Zusammenfassung Durch das Studium von Leben und Werk von George Martine, der augenscheinlich der erste Anwender der Prinzipien der Differentialthermoanalyse war, wird offenkundig, daß sein Wesen bisher wissenschaftlich (und möglicherweise auch medizinisch) nicht gebührend gewürdigt wurde. Eine komplette Bibliographie seiner Schriften ist beigelegt.

---

. , , , , , ( ) . .

---

---

The author expresses his sincere gratitude to Mr R. N. Smart of the University of St. Andrews Library, Mr A. J. Clark, Deputy Librarian of the Royal Society, Mrs. J. Currie and Ms. J. Archibald of Edinburgh University Library, Dr. H. MacDonald of the National Library of Scotland, Ms. J. A. Beavan of Aberdeen University Library and all those contacted regarding the existence of a portrait of George Martine for their information and assistance, without which this article could not have been compiled.     

Oxidizing properties of alumina towards alcohols. Possible reaction scheme

By chemical trapping, an acyl species has been evidenced in the oxidation of alcohols to carboxylate on an alumina surface. A possible reacton scheme is discussed.

---

. .

     

Effect of inorganic salts on the process of competitive hydrogenation of 2-methyl-3-butene-2-ol and 2-phenylpropene on a platinum catalyst

The effect of inorganic salts (NaNO₃, NaCl, Na₂SO₄, NaHCO₃ and Na₃PO₄) on the selectivity of competitive hydrogenation of 2-methyl-3-butene-2-ol and 2-phenylpropene at 20 °C and atmospheric pressure on a 5%Pt/act. C catalyst in methanol solution was investigated. The dependence of the selectivity and of the initial rate of hydrogenation of the given equimolar mixture on the amount of sodium phosphate used in the modification of the platinum catalyst was measured.

---

(NaNO₃, NaCl, Na₂SO₄, NaHCO₃, Na₃PO₄) 2--3--2- 2- 20 °C 5% Pt . Na₃PO₄ .

     

Hreels studies of Hads effect on NO adsorption on Pt(111)

HREELS studies of NO molecular adsorption on clean and hydrogen covered Pt(111) have revealed that a reversible transition between bridge (₁) and on-top (₂) states of NO_ads is realized in the (NO+H₂)/Pt(111) system. In the presence of H_ads the adsorption of NO in the ₁ state is inhibited and the main state of NO_ads is ₂. Upon heating the layer (₂-NO_ads+H_ads) hydrogen desorption is accompanied by on-top to bridge state conversion.

---

NO Pt(III). , (NO+H₂)/Pt(III) (₁) (₂) NO. H NO ₁ , , ₂ NO. (₂-NO+H) NO .

     

Collisional energy transfer in the decomposition of 2-methyloxetane and 3-methyloxetane, I. Gas/gas collisions

The pressure dependence of the unimolecular rate constants for the thermal decomposition of 2-methyloxetane and 3-methyloxetane has been studied. The average energy transferred downward in gas-gas collision was determined by the application of RRKM theory and a stepladder model of energy transfer.

---

2- 3-. , - , .